Growing heifers - Department of Primary Industries · Calf rearing 2.1 Record keeping 2.1 ... The...

D A I R Y L I N K — G R O W I N G H E I F E R S

Growing Heifers

Ray Johnston, NSW Agriculture, Gloucester

Dick Buesnel, NSW Agriculture, Bega

John Moran, Agriculture Victoria, Kyabram

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Alex Ashwood, Program Leader (Dairy Nutrition), WollongbarAgricultural InstituteStephen Jagoe, District Veterinary Officer, Rural Lands Protection Board,BegaRobin Dobos, Research Officer, NSW Agriculture, EMAI

Acknowledgments

Mark Freeman, Research Scientist, Department of Primary Industries andFisheries, TasmaniaDoug McLean, Research Scientist, Flaxley Agricultural Centre, SouthAustraliaIan Lean, Consultant, Bovine Australasia, NSWJudi Miles, Dairy Farmer, Mitiamo, VictoriaGraeme Schuhcraft, Dairy Farmer, Bega NSWIan Sawyer, Nutritionist, Millmaster Pty Ltd, NSWPhil Grant, Consultant, formerly with Veanavite Pty Ltd, VictoriaBob Elliot, Nutritionist, Roche, QueenslandAllan Glassop, District Veterinary Officer, Rural Lands Protection Board,Wingham

Ross Coomber, District Livestock Officer (Dairying), NSW Agriculture,Coffs Harbour

Edited, designed and desktop published by Ann Munroe, Sydney, andMatthew Stevens, ScienceScape Editing, Sydney

© NSW Agriculture 1997

This publication is copyright. Except as permitted under the CopyrightAct 1968 (Cth), no part of this publication may be produced by anyprocess, electronic or otherwise, without the specific written permissionof the copyright owner. Neither may information be stored electronicallyin any form whatever without such permission.

NSW Agriculture does not accept any form of liability, be it contractual,tortious or otherwise, for the contents of this publication or for anyconsequences arising from its use or any reliance placed upon it. Theinformation, opinions and advice contained in this publication are of ageneral nature only and may not relate or be relevant to your particularcircumstances.

Pesticides Act 1978

Under the Pesticides Act you must use only a registered chemical. Itmust not be used for any purpose or in any way contrary to the directionson the label unless a permit has been obtained under the Act.

Agdex 413/23

ISBN 0 7310 9816 1 (Dairylink monographic series)ISBN 0 7310 9819 6 (Growing Heifers)


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John Craven, ProgramManager, FarmProduction, DRDC

Kevin Sheridan,Director-General,NSW Agriculture

Reg Smith, President,NSW Dairy Farmers’Association

Foreword

Dairying is one of the most progressive rural industries in NSW.This is evidenced by substantial changes in herd sizes and increasesin production by cows and from farms.

An outcome of these increases is that management has becomemore complex, requiring greater knowledge and technical skills.

As farmers become more competitive through increases in bothproduction and productivity, they will require even better technicalinformation and management skills. Most important, they will needto know how to use the information in improving whole-farmperformance and profits. This statement is supported by results ofvarious Dairy Research and Development Corporation workshopsand NSW Dairy Farmers’ Association surveys, which have clearlyindicated that farmers require technical packages that are current andrelevant.

DairyLink is a series of integrated information packages that lookat aspects of pasture, herd and feed management, and suggestpractical ways of getting the best from your cows and pastures. TheDairyLink series is a result of collaboration between NSWAgriculture officers, agribusiness and farmers.

The packages will be the basis of workshops and meetings forNSW dairy farmers.

DairyLink has much to offer the NSW dairy industry in helpingimprove farm productivity and profitability. We encourage farmers toattend and participate in the DairyLink workshops and meetings.

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Preface

DairyLink is an innovative concept that introduces you to someimportant technical areas to help improve farm productivity andprofits.

The modules in the series are of value to farmers, students,consultants and extension service providers.

DairyLink consists of the following information packages:

Establishing PasturesManaging PasturesGrowing HeifersRealistic RationsConserving Feed

The modules have been developed as technical manuals andfarmer-friendly booklets, and are linked to the Tocal DairyHome Study course.

I would like to take this opportunity to acknowledge andthank the various technical teams for doing an excellent job. Ialso appreciate the funding and support provided by DRDC.

Alex AshwoodDairyLink Series Coordinator

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Contents

Introduction

Section 1The benefits of good heifer management 1.1The importance of reaching good target weights 1.1Your heifer management program 1.3

Section 2

Calf rearing 2.1Record keeping 2.1Housing 2.1General management 2.4Feeding 2.5Health 2.10Budgeting 2.15Contract calf rearing 2.18

Section 3Growing heifers from weaning to calving 3.1Growing management 3.1Feeding 3.1Monitoring live weight gains 3.2Mating 3.5

Section 4Contract rearing of dairy replacements 4.1Introduction 4.1Payment 4.1Drawing up contracts 4.1Other issues 4.2

Section 5

Animal welfare 5.1

AppendixesAgriculture Victoria Agnotes:Comparing the cost of supplements on the basis of their nutritional valueHealth and mating management of heifers from weaning to calvingHeifer nutrition from weaning to first calvingHow to stomach tube a calfNutritional scours in milk-fed calves—causes and treatment

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Further information

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Introduction 1

Introduction

Many aspects of calf rearing and heifer management havechanged on dairy farms in the last 5 years.

As production levels have risen, so has the need for well-grown high genetic quality heifers to be calved at 2 years of age.Well grown heifers will increase farm profitability, with highermilk production, better reproductive performance and extendedproductive life in milking herds.

The purpose of this manual is to describe the steps requiredfor successful management to achieve those targets.

Calves must obtain the best possible start in life. Bestmanagement practices for colostrum feeding, nutrition, housingand husbandry are outlined here. The requirements for continuedgrowth in the important post-weaning period are covered, withrecommended target weights for mating and pre-calving.

Information on contract calf rearing and heifer growing andbackgrounding is provided, as it is recognised that specialists inthese fields are providing valuable services to the dairy industry.

There is still much to learn about correct nutrition,management and particularly welfare of the modern dairy heifer.

Ray Johnston

NSW Agriculture

PO Box 108 Gloucester 2422

Phone (065) 58 1707

Fax (065) 58 2554


Introduction 2


1.1

The benefits of good heifermanagement

The aim of calf rearing should be ahealthy, fully weaned calf at its targetweight at 12 weeks of age. This should bethe first step in your overall plan to calveyour heifers at 2 years at desirablebodyweights (see Table 1.1).

Good heifer management increasesyour profits because:

• first lactation milk production andlifetime milk production are increased

• there is less culling for failure toconceive or poor production

• reproductive performance is better

• fewer replacement heifers need to bereared

• genetic potential is maximised.

Unsatisfactory calf rearing systemsresult in high labour requirements, lowergrowth rates, and costly health problems.

The Best Practice Principles chartoverleaf shows the inputs, managementgoals and advantages of good calf rearing.

The importance ofreaching target weights

If your 2-year-old heifers reach their targetlive weights at calving, their milkproduction and reproductive performancewill be maximised. Minimum target liveweights for Holsteins are 330 kg at matingand 550 kg at calving (230 kg and 400 kgfor Jerseys). For more details see Table1.1.

The target weights recommended in thetable are for animals that will be milkedon pastures and fed supplements toproduce 6000-8000 L (Holstein-Friesian)or 4500-5000 L (Jersey/Guernsey) of milk

for each lactation. These weights can beachieved under normal commercial dairyfarm conditions if you have a well plannedheifer management program.

There is a range of target weights foreach age group, depending on farmers’goals. There is a large amount of variationwithin herds and among farms. ForHolstein–Friesian x Jersey heifers assumethat the live weight targets are half-waybetween those given for the purebreds.

Table 1.1: Target live weights (kg) forHolstein–Friesian and Jersey heifers

If you don’t manage your heifersproperly they will not reach theirminimum target weights at critical stagesof growth. This means your profits will bereduced, because:

• the heifers will be older at calving, soyou will need to run more replacements

• oestrus (which is determined by liveweight) will be delayed

• undergrown stock will try to catch uptheir weights in subsequent lactationsat the expense of milk production


1.2

• selection and the rate of genetic gainwill be slower

• late calving heifers may have morecalving problems.

Increased milk production

Tasmanian studies have shown that one ofthe most important benefits of having thecorrect weight for age at calving isincreased milk production (Table 1.2).

Studies in NSW and Victoria haveshown similar figures. Two-year-oldheifers produced an extra 1000 L in theirfirst lactation if they calved at 525 kg(peaking at 25 L/day), rather than if theycalved at 425 kg (peaking at 20 L/day),under similar management.

1000 L x 30 c/litre (average price) =$300 extra per heifer for the first lactation.

Subsequent lactations will return highermargins.

Reduced wastage

New Zealand studies have clearlydemonstrated the benefits of improved

Principles of Best Practice

Management Goal AreasEarly Calf Management inputs

Good Management Advantages Other Calf Management Inputs

Source: Department of Primary Industries andFisheries, Tasmania

Table 1.2: Potential production increasewith each 1 kg increase in heifer liveweight at calving


1.3

Table 1.3: Effect of live weight on percentage of empty heifers and on cull rates

heifer weights. Table 1.3 shows that as theaverage live weight increased in 2-year-old heifers, fewer were empty and fewerwere culled for poor production.

Better reproductiveperformance

The onset of puberty and start of cyclingare related more to weight than to age.Conception rates are lower in lighterheifers, and they have more calvingproblems.

Fewer replacements

The number of heifers needed is directlyrelated to the age at first calving and thereplacement rate on the farm. For example,assuming an average culling rate of 30%and an average age at first calving of 28months, Table 1.4 shows that you wouldneed about 77 heifers per 100 cows—77%of your herd size (milking plus dry cownumbers). It appears that many farmersraise too many heifers at a real cost to theiroverall operations. By reaching targetweights on time you can reduce the number

of replacements required and the totalrearing time.

Bottom line economics

Heifers weighing 100 kg more at 2 yearsare likely to produce 2500 L more milkover their lifetimes. This would return anadditional $750 at 30c/litre (average milkprice). They would also return extramoney as cull cows (say, 100 kg at 80c/kg live weight = $80) and produceheavier calves.

The additional cost of grain for theextra growth and milk production wouldbe, say, $540 (3 tonnes at $180/tonne).This leaves a $290 profit per cow—andyou also get faster genetic gain and haveto keep fewer replacements.

The management of heifers should beplanned from the day they are born. Goodrecord keeping is essential and cannot beover-emphasised.

Your HeiferManagement Program

Table 1.4: Effect of age at first calving and culling rate on numbers of replacementsneeded to maintain static herd size of 100 head


1.4

Replacement heifermanagement program forachieving target weights

Birth–2 weeks: Provide colostrum, dipnavel (7% iodine solution), removesurplus teats, identify calf, house properly.Introduce starter meal; dehorn.

6 weeks: Weigh, check feed intake, weanif eating 0.5–0.75 kg a day of a 20%protein concentrate.

8 weeks: Vaccinate for clostridial diseasesand leptospirosis.

12 weeks: Check weight and bodycondition and revaccinate.

6 months: Check weight and bodycondition and assess.

9 months: Check nutritional needs (goodpasture and/or supplements).

12 months: Check your drenching andvaccination program.

14–15 months: Check weight for age;heifers that have reached their targets maybe synchronised and mated (preferablywith AI and a follow-up bull).

18–20 months: Pregnancy test and checklive weight targets.

20–24 months: Check weight andcondition score. Drench. Before calvingintroduce to milking shed and farmroutine.

Calving: Check target weights.Revaccinate for clostridia andleptospirosis.

Having healthy, contented and well grown heifers can maximise your genetic gains.Photo: D Rosenbaum, Gloucester.


2.1

For successful calf rearing you mustidentify your targets and prepare a plan.You should plan for:

• setting up a recording system

• adequate housing

• good management

• proper feeding (including colostrumfeeding)

• formulating a health check list

• preparing a budget.

Table 2.1: Sample chart for recordingcosts to weaning

Record keeping

Setting up a simple record keeping systemis essential. Calves must be correctlyidentified with devices such as eartags.

Record the following:

• date of birth

• twin/calving difficulty

• cases of illness

• date and type of treatment

• weight at birth and l2 weeks

• if purchased, where and when

• mortalities and cause (if known)

• date of vaccination

• date of deworming.

Records will allow you to compare calfrearing with industry targets. Table 2.1might help you to assess your costs.

The risks of selling calves withdetectable residues are too high not tokeep records in an easy and accessiblemanner.

Housing

To encourage rumen development andoptimum growth rates, calves should haverestricted access to pasture. This means

Item Quantity (kg) Cost($ per

day or calf)

Milk/milk replacerPelletsStraw/hayBeddingLabourAdditivesHealth (vaccines, drenches etc)DisinfectantsSundries

(buckets etc)

Calf rearing

calves should be housed for the first 10–12 weeks of life.

Where possible, keep calves in separatepens for the first week. This permits easymonitoring and early detection andtreatment of any health problems. Earlydetection is critical for quick recovery andpreventing deaths.

After an initial period of 1–2 weeks,calves can be put into batches of up toeight in each pen. If calves arepermanently housed inside they will needto be kept in smaller batches than if theyare housed overnight with shelteredoutside runs; calves need a pen area of 1.5m2 each.

Permanent shedding

Keep the shed dry and draught-freeat calf level

Wet windy conditions create stress, whichcan result in scours and possiblypneumonia. Keep sheds clean, dry anddraught-free to above the height of thecalf. At the same time make sure there is


2.2

good ventilation; if you can smellammonia, they can get pneumonia.

Deep litter bedding or wooden gratingis ideal as flooring. If sawdust is used asbedding it should be fresh, clean and dry.

Wooden grating must be well above theground and enclosed on the windward sideto maintain a draught-free environment.

Maintain hygienic conditions

At the end of each calf rearing seasonremove the bedding and clean the shedout. If your calf rearing is seasonal, a spellof 3 months combined with effectivedisinfection will ensure a hygienicenvironment for the next calves. If yourcalves are reared continuously, after eachbatch of calves is put out you will need toclean the shed and all the equipment andsurrounds to remove dry manure and feedresidues. Sterilise by spraying with aneffective disinfectant such as Virkon® orAkricide®. These disinfectants can bemisted throughout the shed while calvesare still inside; nevertheless, sheds are bestdisinfected between batches. Allowingextra shed room for the number of calves

Ventilation is critical in calf sheds. Photo: R Johnston, Gloucester.

reared will allow some pens to be restedon a rotational basis.

Never use a high pressure hose to cleanthe manure out of your sheds if calves areinside; this kind of hosing makes thecalves breathe in atomised faeces andbacteria, making them more susceptible topneumonia.

Overnight shedding withdaytime mini-paddocks

This system is effective for batch rearing.It minimises contamination of the shed,while allowing calves to sleep overnightand providing shelter during wet, windyweather. If you use this system, make surethat your calves eat the necessaryconcentrate ration essential for growth andearly rumen development.

It is essential that mini-paddocks haveshelter from prevailing winds. This can beprovided by specially planted windbreaksor strategically located buildings. Treatcalves with an effective drench beforechanging paddocks.

Train calves to use the shelter by


2.3

placing the concentrate feeder in or next tothe shelter areas.

Outside rearing

If you are planning to rear calves outside,consider shedding them for the first twoweeks.

Make sure quality fresh, clean water andstraw or hay are always available. Placefeeders and straw/hay racks high enough toprevent contamination with faeces. Cleanout stale feed daily; this will encourageyoung calves to have a high intake ofconcentrate and achieve target live weightgains.

Flooring in sheds can be 50 mm x 25mm timber slats, with a 30 mm spacingto allow manure to drop away fromcalves. Photo: R Johnston, Gloucester.

A calf shed need not be an expensivestructure, but it should be built in a way thatmakes it easy to clean and keep clean.

The shed should be well ventilated; itshould be open from one metre high butdraught-free. Preferably it should be openon all sides, or at least open to the north ornorth-east so that it gets as much sunlight aspossible. Lack of ventilation causes anincrease in the humidity and temperatureinside the shed and creates the perfect

Shed design

environment for bacteria and viruses tobreed and survive. These are breathedinto the lungs and infection can occur.The build up of gases such as ammoniaalso damages the lungs and makes themmore susceptible to infection.

The type of flooring is important; thefloor should be kept clean and dry at alltimes. The following flooring systemshave been successfully used and areworth consideration.

Wooden grating

A wooden grating, consisting of 50 mmx 25 mm timbers spaced 30 mm apart, isplaced a minimum of 300 mm above aconcrete sloping floor.

This arrangement allows the urineand dung to pass through the grating to

the concrete below. Remove the calvesfrom the shed if you are using a highpressure hose. You can also use floodwashing to remove dung and straw; acheap and effective arrangement is a200 L drum cut sideways and counter-levered to tip when it is full of water.

Wire mesh

Wire mesh suitable for calf shed flooringis available. It is designed specificallyfor pig pen floors; the openings are12.5 mm x 150 mm. The mesh is weldedto a metal frame and positioned about300 mm above the concrete floor. It maycause problems with sore joints at theknees and hocks, and it appears thatwoven mesh is better.

Deep litter

About 300 mm of litter—dry sawdust,wood chips, straw or rice hulls—is placed


2.4

in the shed and ‘topped-up’ progressivelythroughout the rearing season. Excess dungon the surface must be removed beforeeach topdressing of fresh material.

Note: Do not use green sawdust as it maycause problems with navel infections;straw is safer.

Remove the deep litter from the calfpens at least once a year, and thoroughlyclean and disinfect the shed to prevent thecarryover of disease.

if it is done when animals are young(before 4 months old). Calves are usuallydehorned when they are 2–3 weeks old,using one of the following methods:

• a dehorning iron—a hot electric ironheld over the hornbud for about 30seconds. This operation is clean andpermanent and highly recommended.

• chemicals—caustic potash (rather thancaustic soda) is rubbed over thehornbud. This is easy to do, neat andinexpensive. Calves treated withcaustic sticks or caustic paste should besheltered from rain for at least a dayafter treatment. Be careful: there is adanger of calves rubbing against eachother in cramped areas.

• a scoop (or cup) mechanical dehorner.Calves older than 2 months can beeasily dehorned with one of these. Thismethod ensures that all of the growinghorn is removed. When heifers areolder, the operation is more difficultand the resulting poll is not so neat.

General management

Management factors such as dehorning,drenching, cleaning calf sheds, ensuring aclean water supply and vaccinating mustbe carefully planned.

Dehorning

Horned animals can cause injury to othersin the herd and to people working withthem. Dehorning is simple, safe and clean

Rice hulls are another alternative as a bedding material. Here, half the area is forbedding (rice hulls), with concrete for feeding and watering. Photo: D Rosenbaum,Gloucester.


2.5

Removing supernumerary teats

Supernumerary teats are generally smallerthan the other teats, and if they are notremoved they can get in the way atmilking time.

They can be removed very easily fromcalves up to 2 months old—hold teatswith the fingers and cut them off at thebase with sterilised scissors. If they areleft on until the cow calves, their removalbecomes a job for the vet.

Identification

If you want to run a good herd breedingand a management program you mustclearly identify all animals within theherd.

You should put a permanent,distinguishing mark on all calves that arelikely to be reared as herd replacements.Do this as early as possible after the calf’sbirth. Then write the breeding particularsof the calf, together with its identity markor number, in the herd records.

A number of methods have been usedto identify calves, but the most successfulhave been ear tags, ear tattoos and freezebranding.

Ear tags

Ear tags have been used for many years,with mixed success. The larger plastic tagshave the advantage of being relativelyeasy to read, but tag losses have beenhigh. Pre-numbered brass tags are now apopular means of calf identification, withfew losses if they are correctly appliedand placed.

Ear tattoos

When ear tattoos are property appliedthey are a very effective and permanentmethod of identification. Ideally, theyshould be coupled with some other morevisible form of identification, such as eartags. The ear tattoo may be difficult to

read in a black ear, but using green ink orpaste may help overcome the problem.

Freeze branding

Freeze branding using liquid nitrogen, ordry ice and methylated spirits, is popular;the animal suffers little pain and hidedamage is minimal. Using dry ice andmethylated spirits will produce morewhite hair and a more reliable result thatliquid nitrogen.

White-haired animals will need alonger branding time to kill the hairfollicles; the branding leaves a bare patchsimilar to that left by acid branding.Brands are usually applied to animalsheavier than 200 kg or 12–15 months old,as brands on younger animals will distortwith growth.

Brands can also be acid, caustic or hot-iron.

Drenching

On many properties severe calf lossesfrom infestation with internal parasites(worms) are common. The trouble isparticularly prevalent if calves areconfined to small, dirty yards or sheds, orare grazed continuously in small

paddocks. Calf paddocks normallybecome heavily infested with worms afterseveral batches of calves have been rearedon the one area in the same season. Fortreatment, follow the recommendations ofyour local veterinarian.

bacteria and must absorb the antibodiesthrough the wall of the intestine to gain

Colostrum for a super start

Colostrum is simply the first milkproduced after calving; it containsantibodies against all the bacteria the cowhas come in contact with. The calf is bornwithout protection against infective

Feeding


2.6

protection. Colostrum has more than twicethe amount of total solids of whole milkand initially about five times the levels ofprotein and vitamins A, D and E. Within 2days of calving these levels are about thesame as those found in whole milk.

The antibodies in colostrum transferpassive immunity from the mother to thecalf. A calf must get adequate colostrumfrom its mother or from other freshlycalved cows in the first 6 hours of life.This is crucial; the alternative is a disease-prone calf.

For a super start, a calf needs to beborn on a dairy with ‘colostrumconsciousness’, where rearers know thethree Qs of feeding colostrum:

• quickly—as soon as possible(preferably within 6 hours of birth)

• quality—only the best

• quantity—at least 4 L.

Stomach tubing

To reduce losses and sickness, stomachtubing of colostrum is becoming part ofAustralian calf rearing. The stomach tubeis a semi-flexible piece of plastic tubingwith a pear-shaped end designed to beinserted easily into the oesophagus but notinto the lungs. It is usually attached to aplastic container holding the liquid to befed.

Four litres of colostrum should be fedto give enough antibodies. Some peopleprefer to use a nipple bottle rather thanstomach tubing, but this takes longer andit is unlikely that a calf would drink 4 L.If calves get the initial 4 L by tube theyusually won’t need another feed for 24hours.

Tubing a calf is not a major drama, butthe first time it might pay to get somecoaching. Preferably have the calfstanding. Leaving the head in a positionthat feels comfortable for you, pass thetube gently over the tongue. At this stage

the calf will start chewing andswallowing; the tube can now be passeddown into the oesophagus. When thebulge at the end of the tube can be easilyfelt as it moves down the oesophagus(indicating that the tube is not in thewindpipe) feeding can start. When feedingis over remove the tube slowly. Clean anddisinfect it, then leave it to drain and dry.Stomach tubes are available from yourlocal veterinarian or farm supply store.

Providing 4 L of colostrum through astomach tube is a recommendedmanagement practice to give calves the‘kick start’ they need for life.

For further information on stomachtubing, see the Agriculture VictoriaAgnote AG0503, How to stomach tube acalf, included in the Further Readingsection of this manual.

Colostrum quality

The quality of colostrum can be enhancedby vaccinating cows before calving andagain 6 weeks later for E. coli andsalmonella and with 7 in 1. Thereafter, abooster dose about 2 weeks before calvingis all that is needed. Milk freshly calvedcows as soon as possible, as reabsorptionof antibodies begins immediately aftercalving.

Colostrum quality can be measuredusing a colostrum tester (Calf Guard®);these are commercially available throughall veterinarians or Northfield Laboritoriesin South Australia. Another way ofassessing antibody transfer in the calf is touse a commercial blood testing kit. Thelevel of antibodies in the blood indicatesthe calf’s ability to fight infection; if youfind it is low you can give the calf extracolostrum within 36–48 hours of birth.

If you decide to freeze somecolostrum, try to collect it from maturecows that are among the lower producers,as they tend to have the highest antibodylevels. Young cows have a lower natural


2.7

immunity than mature cows. Cows thatsuffer from sickness or stress at calvingwill also have lower antibody levels.Frozen colostrum should be thawed in abucket of warm water. There is still someconcern about using microwave ovens forthawing, but if you use the proper defrostsetting the antibodies should not bedamaged.

Colostrum can be stored in therefrigerator for a week or so withoutaffecting quality. Frozen colostum can bestored for 6–12 months.

the market vary widely in quality, so thisshould be checked, either by using yourown experience or by adding some junkettablets to test their clotting ability.

There are two types of milk replacers:those that use butterfat as the basic energysource and those containing tallow.Quality butterfat-based products arepreferable. If you have to use tallow-based products because the others are tooexpensive, make sure you choose a highquality one. Table 2.2 lists the desirablecharacteristics of high quality replacers.

Milk feeding

Whole milk is the natural food for youngcalves. It is especially preferred forminimising digestive upsets. However,milk replacer powders are widely used insome cases for reasons of price anddisease control and the fact that they canbe fortified with vitamins, minerals andionophores. The milk replacers now on

• Tallow-based milk replacer should befed only once a day, because it takeslonger for the clot to be digested, andfeeding twice a day can result inscours.

• Feed milk at the same time andtemperature each time.

• Make sure there are no sudden changesin the ingredients and amounts beingfed.

• Weigh milk powder ingredients beforeyou mix them.

• To mix milk replacer, add the powderto half the desired volume of warmwater (at 36°C). Stir vigorously with awire whisk. Add the remaining volumeof warm water.

• Antibiotic-contaminated milk is notsuitable for young calves as there maybe a problem with residues in meat.Also, problems can arise with antibioticimmunity and death of useful bacteria inthe stomach and intestine.

• Calves can be raised successfully onboth teat and bucket systems. Choosethe one most appropriate to yoursituation.

• Provide clean water. On each day of thefirst week turn the water off for 12hours before milk feeding to make surethe calves will drink their milk.

success with a single 3–4 L whole milkfeed from the first week, but there is adanger of overfeeding and scours inthis approach.

Milk replacement tips

• Some calf rearers have achieved

The water supply

A liberal supply of fresh, clean drinkingwater is necessary in any calf rearingprogram. If your calves are on a once-daily milk feeding program you shouldcheck their water twice a day, especiallyin hot weather.

Table 2.2: Characteristics of high qualitymilk replacers

17% or higher fatMinimum 24% proteinFat particle size under 4 microns if tallow-basedLow temperature dryingWill clot


2.8

If you are using a high quality full-cream milk follow the instructions.

Early weaning off milk at 6 weeks of ageon to high quality pellets and straw offersmany advantages.

For more details of early weaningmethods see Agnote 2/099 Early Weaningof Dairy Calves.

Later weaning direct to pasture

quality pastures are available.

To continue desired growth rates afterweaning, calves need to be provided withsome form of concentrate until high

For once-daily feeding, if you areusing milk replacer, see Table 2.3 for theproportions of milk replacer and water tomix up for different ages. If you are usingboth milk replacer and whole milk, seeTable 2.4 for the correct proportions to useat different ages.

These include fewer health problems,the lower cost of the concentratecompared with milk, lower labour costsand greater rumen development.

Starter mealsCalves need high energy and high proteindiets; examples of feed mixes are shownin Table 2.5. When you are starting calves

on meals, feed only small amounts initiallyto keep the feed fresh; calves will not eatfeed that is contaminated with saliva. Oneintroduction technique is to place somemeal in the bucket or trough after milkfeeding.

Clean, fresh straw should be available in early weaned systems. Photo: R Johnston,Gloucester.

Early weaning to concentrates

Developing the rumen inconcentrate-fed calves

From day 2 in the program, provide freeaccess to a palatable, clean, freshconcentrate supplement.

If you plan a restricted milk feedingprogram, calves should have access to adlib pellets from day one to encourageconcentrate consumption.

Young calves up to 6 weeks old need ahighly palatable concentrate supplementwith a minimum of 18% protein and aminimum of 11 MJ of ME/kg of dry matterto provide enough nutrients for earlydevelopment of the rumen and rapidgrowth. Feed this supplement until largerbreed calves reach 100 kg live weight (atabout 12 weeks).

If you are home-mixing your feeds, besure you get an accurate feed analysis so

you can be sure that the protein and energylevels reach those recommended for rapidgrowth. Home mixes should include a


2.9

Table 2.3: Using milk replacer and feeding once a day

Table 2.4: Using whole milk or colostrum with added milk replacer, feeding once a day

Notes:Chopped high quality hay (lucerne or oaten) can be included at 10%; avoid chopping finer than 20mm.Protein supplements fed to calves should contain high quality meals.Ionophores (such as monesin) should be included only if well mixed into the feed.

Table 2.5: Calf starter mixes

should be highly palatable. In some casesmolasses can enhance the palatability.

Any changes in feeding managementshould be phased in gradually. Monensin(Rumensin®) or avoparcin (Avotan®) canbe included in all concentrate rations toincrease the nutrient absorption of thesupplement.

Calves should have access to cleanstraw from the start of the program. Strawprovides a ‘scratch factor’ that will helpdevelop the rumen while maintaining

rumen pH levels, due to the large amountof saliva produced by the chewing.However, do not provide good quality hayon demand—calves will consume toomuch, reducing their concentrate intakeand growth rate. The best practice is toprovide the best quality feed at all times,but limit the fibre intake to 10% of thetotal dry matter intake.

Calves can be weaned from milk whentheir concentrate intake reaches 0.75 kgper head per day. This should happenwhen they are 4–6 weeks old.

vitamin and mineral premix. Concentrates


2.10

Health

General issues

What is a healthy calf?

Normal physiological values for healthycalves are:

Average Range

Rectal temperature 38.6o C 38 to 39.3o CHeart rate (pulse) 70/min 40 to 100/minBreathing rate 30/min 25 to 40/min

These values apply to normal, healthycalves at rest under mild climaticconditions. The heart rate and breathingrates can vary markedly if the animal isexcited or frightened, or if the weather isvery hot. Heavy, laboured breathingindicates respiratory problems.

Setting up a disease managementplan

To make sure your calves are healthy andreach their target weights you need tohave a disease management plan. Thisshould include:

• a program for routine cleaning anddisinfecting facilities and equipment

• a twice-daily routine for observingcalves for early detection and treatment

• a system for identifying and recordingsick calves, and a treatment regime

• hospital pens for sick calves, plussupplementary heating; sick calvesshould not be completely isolated—ifpossible they should be within sightand hearing of their mates

• a stock of medication on hand—especially electrolytes and disinfectants

• access to a vet with experience in thetreatment of calf diseases

• equipment for stomach tubing for bloatcontrol and electrolyte administration.

Observing calves for illness

Success or failure in rearing calves willdepend to a great extent on your attitudeto the calves and your ability to reactpromptly to the calves’ numerous signals.If you are feeding once daily you shouldvisit the calf shed or paddock at leasttwice daily.

Calves charging your knees andrunning around the pen are healthy. Suchcalves rest in a curled up position with

Calves reared in small groups can be easily checked for changes in health. Photo: THickman, Gloucester.


2.11

* Amount of fluids lost as a percentage of calf’s

bodyweight

Table2.6: Measuring dehydration

Simple shade structures will alleviate heat stress in summer. Photo: R Johnston,Gloucester.

feet tucked under them and heads backalong the body. They appear relaxed andhave regular breathing rhythms. Somehealthy calves may also rest flat on theirsides.

A calf resting in the corner of its penwith its head turned away from its pen-mates should not be ignored. Get the calfup. If it stretches, it’s okay. If it doesn’t, itrequires further attention. Sick calves lackinterest and are listless and apathetic.They do not move when approached andoften stand with their ears lowered andhead down.

Look quickly over each pen of calves,then be more specific and check anysuspect calves’ noses for dampness (thenose should be moist), and the ears fortemperature. Listen to their breathing,noting any ‘rattles’ or laboured breathing.Lift their tails and note the state of anyfaecal residues. Look at their feet and legsfor signs of swelling. For the first week to10 days, check the navel area for signs ofinflammation.

intravenous fluids administered by aveterinarian. Calves less than 8%dehydrated and still drinking can berehydrated by mouth with electrolytesolutions or by stomach tube. Table 2.6shows how to assess the degree ofdehydration.

The skin fold test simply involvesusing the fingers to pinch up a fold of skinalong the neck. The test indicates the timeit takes for the skin to bounce back;normally this is less than half a second.Once you have determined the percentagedehydration you can calculate the fluidrequirements. For example, for a 40 kgcalf that is 6% dehydrated:

Dehydration

If a calf is profoundly dehydrated (bodyweight reduced by 10—15%) it will need


2.12

yoghurt in a drum of milk starts thefermentation process, and the milk orcolostrum can be topped up daily.Alternatively, probiotics may be added tomilk just before feeding to supplybeneficial bacteria to the intestines to helpprevent scours. Antibiotic-treated milkcannot be used with this method.

Good hygiene is extremely important,as it limits the number of germs cominginto contact with the calf. Separateaffected animals to prevent spread of thedisease within the group. Limit stresseslike overcrowding, sudden changes of dietand chills from wet conditions.

Vaccinating mothers can help protectcalves from scours. Commercial vaccinesare available for preventing E. coli,Salmonella and clostridial infections.

With any disease, don’t hesitate to askfor advice from your private veterinarian,Rural Lands Protection Board districtveterinarian or animal health adviser—you can’t avoid problems if you don’tknow about them first!

Taking a calf’s temperature

The normal temperature range is 38.0–39.3oC.

Temperatures above 39.5oC generallyindicate some infection problem in thecalf. Low temperatures can indicate poorcirculation and shock—but makeallowances for the ambient temperatureand shade.

An essential tool for a calf rearer is thethermometer; you can use it to detectfevers and monitor the success oftreatments. Two types of thermometers areavailable.

• mercury bulb thermometer—cheap buteasily broken

• electronic thermometer—expensive butlong lasting.

You can get thermometers from yourveterinarian or chemist.

Fluid volume needed for replacement

= 40 x 6% = 2.4 L.

Fluid volume needed for maintenance

= say, 100 mL/kg/day = 4 L.In this case feed 6.4 L over three feeds

in a day. You can monitor the rehydrationwith the skin fold test.

Electrolyte treatments do not provideenough energy to maintain calves. After24 hours you can reintroduce milk, butcontinue the electrolytes for another 48hours. Separate the milk feeding fromelectrolyte feeding by 6 hours, and set thefirst two milk feeds with junket tablets tohelp the milk digestion.

Antibiotics may be needed, especiallyif the calf remains dull after rehydration.Antibiotics must be used under veterinarysupervision; make sure you keep a recordof treatment.

Prolonged use of antibiotics can causescouring, because it kills the normalbacteria of the bowel. Dosing the calf withplain non-pasteurised yoghurt helps re-establish bowel bacteria.

Probiotics such as Protexin® are nowavailable and can be used instead ofyoghurt to introduce beneficial bacteriainto the calf’s intestines. Because productslike Protexin® have to be registered, thenumbers of bacteria and their stabilityhave been tested and these products canbe expected to give more consistentresults than yoghurts.

Colostrum provides important antibodiesagainst many germs that can affectnewborn calves. It is also ideal for oldercalves, as it has higher levels of nutrientsthan fresh milk (twice the casein, fourtimes the total protein, and 67 times theantibodies) and can provide a protectivelocal immunity on the surface of thebowel.

Fermented colostrum or milk helps

Disease prevention

control calf scours. Placing a tub of plain


2.13

Technique

Insert the thermometer at least 5–7 cminto the calf’s rectum. Make sure the tip ofthe thermometer touches the lining of therectum of the calf. If you are using amercury bulb thermometer, wait at least60 seconds before you read it. Electronicthermometers will ‘beep’ when anaccurate reading is obtained.

Scour prevention and treatment

No doubt the most common cause of calfdeath is dehydration caused by scouring.If a bad dose of the scours doesn’t kill thecalf, the damage done to the villi on thewalls of the small intestine that absorb thenutrients can leave the calf unable to useall the food it consumes, and the result is a‘bad-doer’.

Causes of calf scours

Stress. One of the main causes of scours

heat powders that are incorrectly dried,tallow that is not homogenised properly,milk replacers containing a highpercentage of whey, and some milk-basedproducts used to cheapen replacers.

Bacterial infection and dehydration.Bacteria are not considered a major causeof calf scours. However, once a calf startsscouring, the conditions are ripe for aninvasion of harmful bacteria, such assalmonella and certain strains of E. coli.These bacteria cause major damage to theintestine walls, preventing the calf frombeing able to absorb nutrients and fluids,and causing fluids to be passed from thebody into the intestines and out in thescour. This loss of fluid or rapiddehydration is the major cause of calfdeaths.

Bacteria on their own can sometimescause calf deaths. During the first 8 hoursafter birth, the walls of the calf’s intestinesare ‘open’ to allow antibodies to pass intothe bloodstream. If, during this time, thecalf takes in any harmful bacteria fromcontaminated cows’ milk or infectedsurroundings, these bacteria can passdirectly into the bloodstream and causewhat appears to be sudden death somedays later.

Another source of bacterialcontamination is the navel cord. If the calfis born on or lies on contaminated groundwhile the cord is still wet, bacteria cantravel up the cord and enter thebloodstream. Depending on the type ofbacteria, the result can be rapid death,navel infection, or swollen knees, stiffjoints and hair loss.

Preventing and treating scours

The stress scour is difficult to prevent,but can be quite easy to treat. To helpprevent stress scours, don’t feed the calffor 24 hours after it has been removedfrom the cow or bought from thesaleyards; transport it in a well-covered

is stress. The calf is put under stress whenit is taken from the cow, transported anydistance or has its diet changed from adlib cows’ milk to either restrictedwholemilk feeding or milk replacer. Thisstress scour appears 5 to 7 days after thestress occurs.

Excessive milk volume. Another majorcause of scours is overfilling of theabomasum (the fourth stomach). When acalf drinks milk, the milk bypasses thefirst three stomachs and enters theabomasum. Here the milk clots and thenpasses slowly into the intestines to beabsorbed. If the drink of milk is too large,or the calf is under stress, some of themilk overflows or is pushed through intothe intestines before it can clot, andscouring will result.

Poor feed quality. Feeding milk productsor substitutes that won’t clot in the fourthstomach results in scouring or anincreased risk of scouring if the calf isunder stress. These products include high-


2.14

vehicle with dry bedding; and don’t buycalves that look sick or stressed.

You can give calves a drink ofelectrolyte replacer when they arrive, butthey should be allowed to settle downfirst, and certainly should not be disturbedafter the drink. When a calf develops astress scour it can be blocked up withkaolin (powdered chalk). This slows thepassage of milk to the intestines, so thatthe scour is controlled before damageoccurs. Mix enough kaolin with the milkand the scour is stopped almostimmediately; mix too much and the calfbecomes constipated. A stress scour canbe overcome without taking the calf offmilk.

For further infomation on calf scours,see the Agriculture Victoria AgnoteAG0578 Nutritional scours in milk-fedcalves: causes and treatment; there is acopy of this publication in the FurtherInformation section of this manual.

Drenching programs

You must have a strategic drenchingprogram if you want to produce healthywell-grown stock.

Strategic drenching programs areaimed at achieving maximum ‘kill rates’of parasites in the animal, as well asminimising build-up of worm eggs andlarvae on pastures, in order to minimisere-infection of stock.

Drenching times vary with climate,locality, stocking rate, and a range of other

from 3 months of age onwards. Two dosesat an interval of 4–6 weeks are essential,with an annual booster thereafter.

Enzootic bovine leucosis (EBL)

All farmers rearing dairy heifers shouldconsult their local animal health advisorsto make sure they have a fullunderstanding of EBL. A knowledge ofthis disease is particularly important ifcalves are being reared on whole milk,and when animal husbandry proceduressuch as vaccination, dehorning,earmarking and tattooing are being done.

factors, but usually three or four drenchesare needed each year. Consult your localanimal health adviser or veterinarian fordetails to suit your situation.

Vaccination programs

Dairy heifers must be fully vaccinatedagainst clostridial diseases andleptospirosis. A combined vaccine isavailable, and it is usually given any time

In most cases it will be advisable toblood test calves initially, and then retestthem after the age of 6 months, to makesure they are EBL–free.

Johne’s disease

Johne’s disease is a chronic scouring andwasting disease that ends in death. Thereis no vaccination available, and nosuccessful treatment. Make sure all yourcalves come from herds that have had nohistory of Johne’s disease.

Up until 12 months of age calves aresusceptible to Johne’s and should begrazed away from pasture used by maturecattle. The bacteria that cause Johne’s arespread in the faeces of cattle over 2 yearsold.

A blood test is available, but it is nothighly accurate in detecting earlyinfection in individual animals. Again,seek advice from your animal healthadviser.

A Johne’s Disease Markets AssuranceProgram is now available. This schemeclassifies herds not only on the basis oftheir history, but also on the results ofwhole-herd blood testing. A series ofTested Negative (TN) status from TN1 toTN3 has been developed to improve herdcertification. Farmers should seek adviceon the program through the local RLPB or


2.15

their vet.

Other common calf infections

Naval infections, joint ill and pneumoniaare all common problems in calves. Aswith scours, prevention is better (andcheaper) than cure. Good hygiene andmanagement are critical in preventingthese problems. Treatment is not alwayssuccessful.

Pestivirus infection

Pestivirus is a common virus that oftengoes unrecognised in many herds. It cancause scouring, chronic ill thrift andfertility problems. There is no commercialvaccine and no specific treatment isavailable, but it would be advisable todiscuss pestivirus with your veterinarian,particularly if you intend to do artificialinsemination or embryo transfers.

A blood test is available to identifyheifers that are already immune to thevirus.

Bovine ephemeral fever ( threeday sickness)

Three day sickness is a common summervirus in coastal areas. Younger animals areusually only mildly affected, recoverquickly, and acquire a good immunity.Older animals can suffer severe muscleand joint pain and fever, and sometimessecondary complications such as abortion,pneumonia, or even death.

A vaccine is available, and it generallygives good protection against the disease.

Akabane virus

Akabane virus is another coastal summervirus. It causes no observable symptoms,but if the animal is pregnant at the time ofinfection, major problems can occur in theunborn calf. In some cases, the calf maybe born with severe brain damage, while

in other cases calves can have severe limband joint deformities. There is notreatment, and although an effectivevaccine has been developed it is notcommercially available.

Prevention is aimed at trying to ensureheifers are exposed to the virus beforethey become pregnant; in this way theydevelop a strong immunity and suffer nofurther problems from subsequentexposure to the virus. If you are buyingpregnant animals from outside the NSWcoastal area (for example, from Victoria or

animals to the coastal region during theinland NSW), do not introduce these

high risk time for Akabane virus spread(generally January to May).Budgeting

Calf-rearing costs include disease

prevention and treatment, feed, labour anddepreciation on equipment. The greatestsingle cost will be feed. Losses throughdeath must also be included in anycosting.

Costing different feeds for calfrearing

The relative costs of various feeds used incalf rearing, using assumed figures for thedry matter (DM), energy and proteinvalues for ‘typical’ feeds of each type, arepresented in Table 11.

Milk or milk replacer can be costed interms of either cents per kg of dry matter(c/kg DM) or cents per megajoule ofmetabolisable energy (c/MJ of ME) in theproduct. The latter is calculated from fatand protein levels in the whole milk ormilk replacer.

Costs for solid feeds can be calculatedin a similar way to those of liquid feedsonce their costs in dollars per tonne andtheir dry matter or energy contents areknown.

You can buy energy- and protein-rich


2.16

Table 2.7: Costs for dry matter and energy in various calf feeds

feeds already mixed and pelleted ascommercial pellets, or you can blend themon-farm from the raw ingredients to forma balanced concentrate mix. Calf rearingpellets often contain vitamin and mineraladditives, and have higher digestibilityand no dust. However, as shown in calfrearing trials, palatability of feed is thehighest priority.

Commercial pellets, despite beingmore expensive than on-farm mixtures,are usually the preferred solid feed for calfrearers. For the comparison in Table 2.7,commercial pellets have been priced at$300/t. On-farm concentrate mixes havebeen priced at $200/t; this would be theprice for an on-farm mix consisting of80% rolled wheat (at $140/t) and 20%cottonseed meal (at $350/t), plus $18/t forblending and handling.

A mixture of protein meals is best, asthis gives a broad protein base of aminoacids.

In terms of energy, whole milk isgenerally cheaper than milk replacer, butthe energy supplied by both is 3–6 timesmore expensive than the energy suppliedby concentrates. The cheapest source of

feed energy is grazed pasture; the energyfrom pasture costs 20% of that fromconcentrates and only 5% of that in liquidfeeds.

Further details on comparing feed costsare contained in the Agriculture VictoriaAgnote AG0501 Comparing the cost ofsupplements on the basis of theirnutritional value; there is a copy of thispublication in the Further Informationsection of this manual.

Comparing different whole-milkrearing systems

Table 2.8 presents the total costs ofrearing calves to 12 weeks of age using 4different whole milk feeding systemsvarying in labour requirements and feedinputs.

• The cost of whole milk in the artificialrearing systems is either 20c/L or30c/L.

• Concentrate pellets cost $300/t.

• Hay costs $140/t.

• Any pasture grazed by calves is notcosted.

Feed Dry Energy Protein Cost per Cost of Cost ofMatter (MJ/kg (% DM) unit DM (¢/kg) energy

(%) DM) (¢/MJ)

CONCENTRATES

Pellets 90 13 18 $300/t 33 2.5

On-farm mix 90 13 18 $200/t 22 1.7

ROUGHAGES

Lucerne or

clover hay 85 9 18 $7.00/bale 33 3.6

Cereal straw 90 7 3 $3.00/bale 16 2.3

Grazed pasture 20 11 14 $60/t DM 6 0.5


2.17

levels of whole milk twice daily, earlyweaning saved $24 per calf when milkwas cheap and $42 per calf when it wasexpensive. When no colostrum wasavailable, feed (milk, concentrates andhay) accounted for 59–88% of the totalrearing costs.

Whole milk supplied by nurse cows inSystem 4 cost only $10 per calf comparedwith $31 per calf when milk was priced at20c/L in the cheapest artificial rearing,System 3. To cost the milk supplied bynurse cows, it was assumed that it alloriginated from grazed pasture, costing$60/t DM. In year-round calving regionswhere pasture quality can varyconsiderably from season to season,additional concentrates may be needed tomaintain milk yields in nurse cows. Thiswould increase the cost of supplying thatmilk to multiple-suckled calves, but thecost would be unlikely to rise to more than10c/L.

The lower labour costs involved in adlib milk feeding hardly compensated forthe high cost of the milk drunk by thesecalves. The costs for non-feed componentsranged from $22 to $43 per calf, thisvariation being mainly due to the differentlabour requirements. Labour costs per calfvaried from $5 (when fed ad lib milk) to$26 (when fed twice daily).

The full costs for rearing calves to 12weeks can vary from a low of $70 per

• Labour is costed at $10/hour; this isbased on the cost of hired labour.

• Veterinary treatment and drugs cost $5per calf.

• Depreciation on equipment is valued at$4 per calf in all 4 systems.

• Other opening costs in the 3 artificialrearing systems, such as milk feedingand cleaning equipment, are costed at$4 per calf.

• Death rates are 3% or $3/calf in all 4systems.

To allow for the feeding of colostrumduring milk feeding, a second set ofcalculations have been presented in Table2.8, which assumes that the first 180 L ofliquid fed to each calf in the three artificialrearing systems have no cost. Therefore,whole milk requirements are reduced to380 L/calf in System 1, 154 L milk/calf inSystem 2 and nil in System 3.

The largest cash cost is clearly forwhole milk. When compared with the adlib milk feeding in System 1, calves drank40% less milk when restricted to twicedaily feeding in System 2 and 72% lesswhen weaned early in System 3. Thisreduced the total rearing costs by $24 and$48 per calf respectively when milk wascheap (20c/L) and $47 and $89 per calfrespectively when milk was expensive(30c/L).

Compared with feeding restricted

Table 2.8: Total costs ($ per calf) for rearing calves to 12 weeks of age using fourdifferent whole milk feeding systems with or without colostrum


2.18

calf, when early weaning on colostrum, toa high of $190 per calf when feedingexpensive, ad lib milk. Unless more use ismade of colostrum in rearing systems, it isunlikely that calves can be artificiallyreared to 12 weeks of age for much lessthan $100 per calf. This contrasts with the$68 required to rear each multiple-suckledcalf.

Contract calf rearing

A new service is being offered to dairyfarmers, whereby calves are reared off-farm and returned fully weaned.

Calves are transported to the rearer,who provides labour and facilities to early

wean calves and develop their rumencapacity before returning them to theowner. Costs for feed, animal health andtransport are met by the owner, with anadditional charge for labour.

Payment can be based on a live weightgain, for example, meeting a target weightat 10 to 12 weeks, or simply on thesuccessful weaning of a healthy calf.

One contractor in NSW charges $1 aday for labour, with feed, health andtransport on top. This equates to about$150 for 10 weeks.

You should investigate the rearer’sdisease control practices and methods ofminimising cross-transfer of EBL beforeyou send calves off-farm for rearing.


3.1

Growing heifers from weaning tocalving

maintain their weights. Similarly, above acertain level of herbage mass, animals willnot eat more, even if it is available.

For a 200 kg dairy heifer, these limitsare about 700 and 2500 kg DM/ha,assuming that the pasture is leafy greenmaterial, and that it is a temperate rather

Pasture quantity (or herbage mass) isexpressed in kilograms of dry matter perhectare (kg DM/ha).

Once herbage mass drops below acertain level, animals are physicallyunable to consume sufficient pasture to

Pasture quantity

Growing management

Frequently, calves are reared well up toweaning, then virtually left to look afterthemselves. Poorly managed weaners aredisadvantaged for their entire lives.

Aim to calve heifers at about 85% ofthe average mature cow bodyweight of theherd. This means that most of theirgrowing is finished and they can copewith changes of grazing pasture and herdpecking order. Feed can then be directedinto milk, and higher conception rates arealso likely.

Feeding

This section in intended to give you abasic understanding of heifer feeding. Formore details, see the DairyLink manualRealistic Rations.

You must understand pastures if youare going to do an efficient job of rearingdairy replacements growing at 0.7 kg/day.

than a tropical pasture.

Pasture quality

Digestibility (expressed as a percentage) isa very useful measure of pasture quality. Itis strongly related to the energy andprotein content of a pasture, as well as tothe speed with which the plant materialwill pass through the animal.

Quality is complex and is influencedby:

• Species. Legumes usually have higherquality than grasses, and maintainingthem in a pasture will maximise animalperformance. Temperate species suchas ryegrass have higher digestibilitythan tropical species such as paspalum.

• Parts of the plant. The leaf is moredigestible than the stem.

• Stage of growth. Older plant materialis less digestible.

Table 3.1 shows how digestibilitychanges as plants mature.

There is a strong interaction betweendigestibility, herbage mass and animalintake. As pasture quality declines, animalperformance can be maintained byoffering more pasture—that is, decreasingthe stocking rate on the pasture so that theanimals can be more selective in theirgrazing.

Table 3.1: Digestibility at different growthstages


3.2

Note. Once digestibility drops below60%, no matter how much pasture theanimals are offered they will not be ableto maintain their target weight gains—andat 50% digestibility, the animals will belosing weight.

Hay and silage

Both hay and silage can be successfullyused to maintain growth rates if pasturequantity or quality is low. The feed qualityof hay and silage is extremely variable, sotesting for quality is recommended. Thereare several commercial testing servicesavailable, so seek professional advice onthe availability of tests and how best touse the results.

Balancing rations

If you use low quality roughages you willneed to add concentrates to meetnutritional requirements. Stockrequirements are outlined in Table 3.2.

Working out the ration involvesbalancing the difference between theanimals’ requirements for energy, protein,fibre and minerals and the nutrientsavailable from their feed intake.

For more information on nutritionfrom weaning to calving, see theAgriculture Victoria Agnote AG0507,Heifer Nutrition from weaning to firstcalving; there is a copy of this publicationin the Further Information section of thismanual.

Monitoring live weightgains

Under ideal conditions heifers should havea constant weight gain of 0.7 kg/day ifthey are to reach their desired weight-for-age targets. The only time it might bebeneficial to slow this weight gain isduring the second 6 months of life, whenthere is some evidence that with excessivegrowth rates (over 0.7 kg a day) fattytissue may be laid down in the udder.

Compensatory growth after setbacksfrom low feed intake and health problemssuch as worms can only partly make upfor lost gains. If your heifers are well fedand therefore growing well they will beless susceptible to external and internalparasites. They will also suffer less fromtrace element deficiency problems.Regular monitoring and weighing willhelp to highlight any problems.Management can then be changed toovercome the problem and minimise thesetback.

For these reasons it is important tohave an accurate method of assessing liveweight. Also, drench doses are all basedupon live weight, and an error in liveweight estimation could result in eitherunderdosing (ineffective) or overdosing(waste of drench). Under-drenching is themost serious mistake, as it does noteradicate the worm problem and can lead

Table 3.2: Nutritive value of diets recommended for heifers of different ages to grow at0.7 kg/day (NRC 1989)


3.3

to a false sense of security as well ascreating a possible worm resistanceproblem.

Table 3.3: Accuracy and costs of heifer live weight assessment

Assessing live weight

There are various ways you can assessdairy heifer live weights, and they havevarying degrees of accuracy. Generally it’sa case of getting what you pay for. Targetchest girths and wither heights are lessaccurate than cattle scales, but they arehelpful if you don’t have scales. Table 3.3will help you choose.

Visual estimation

Some farmers are very good at guessingthe live weights of some of their heifers,but get most wrong. Estimating liveweights using eyesight alone is the leastreliable method of all.

Girth tape

The girth tape is quite an accurate methodof assessing heifer live weight, althoughaccuracy diminishes slightly with olderanimals. Also, it is hard to restrain olderheifers to place the tape in the correctposition. This method is clearly the mostlabour intensive.

Wither height stick

The wither height stick is a cheap form oflive weight assessment for dairy heifers.The stick is subject to some readerinaccuracy, but over a group of heifers itwill indicate live weights with quite a highdegree of accuracy. The withers are the

highest part of the heifer’s back, behind theneck.

Scales (electronic)

Electronic scales are the most accurate wayof assessing heifer liveweight. Goodquality scales can store heifer liveweightsin a memory to be downloaded to apersonal computer.

Regular weighing, three or four times ayear, tells you not only when heifers havereached target weights, but also howquickly they are growing at certain timesof the year. This will provide a check onthe quality of the pastures and tell you ifany supplements are required.

Using growth charts

There are a number of different types ofgrowth charts. Overleaf are some growthcharts that are a guide to target witherheights at different ages up to 2 years old.One chart gives Americanrecommendations for Friesian and Jerseyheifers, and on the other you can comparesome different Australian recommendationsfor Friesians with the American ones. Byperiodically monitoring your heifers andplotting their wither heights on a chart, youcan see how your feeding management isgoing in relation to the optimum.

Critical periods in live weightgain

In a well managed heifer replacementprogram target weights are reached at a


3.4

Growth charts

Wither heights for age for growing heifers: US recommendations (after J Moran,Agriculture Victoria)

Wither heights for age for growing Friesian heifers: published recommendations(after J Moran, Agriculture Victoria)


3.5

steady growth rate. Your management mustbe especially careful at times that arecritical for weight gain, so that this steadygrowth is not disrupted.

There is a critical period in thedeveloping udder when excessive growthrates can increase the deposition of fattytissue and reduce lifetime productivity. Sofar no one knows exactly when thiscritical period occurs, and exactly whatconstitutes excessive growth rates,although there are some generalguidelines. Some advisers consider thatlive weight gains should not exceed 0.5kg/day between 6 and 12 months, whereasothers recommend gains of less than 0.7kg/day between 3 to 8 months. Clearly itis not desirable to feed heifers abovemaximum growth rates during theirsecond 6 months of life.

Fatty udders are unlikely to be aproblem in pasture-grown heifers,particularly in traditional periods ofpasture shortage. Balancing dietarynutrients (such as supplying enoughbypass protein) may be one way ofmaintaining high growth rates in heiferswithout depositing fatty tissue.

conception rates than lactating cows, asthey do not have the stress of lactation tocontend with.

Some heifers will have shorter standingheat periods than older cows; for thisreason, aids to heat detection (such as tailpaint or heat-mounting pads secured onthe tail head) are recommended.

Drugs used to synchronise heatin heifers

Synchronising heat in your heifers willsave you time and give you good controlover your breeding program. A number ofdrugs can be obtained from your vet:

Prostaglandins

These occur naturally in the body, but canalso be given as drugs to synchronise heat.They work by causing the corpus luteum(the ‘blister’ that forms on the ovary afterthe egg is released) to dissolve.

Progesterone (natural) orprogestogen (synthetic)

Progesterone is produced by the corpusluteum. It is the hormone that ‘organises’the whole cycle, and can also be used tosynchronise heat.

Oestradiol benzoate or oestradiolvalerate

Oestrogens have a similar effect toprostaglandins.

Systems used to synchroniseheat

No one system is guaranteed to get all yourheifers tightly synchronised. All thesystems used require multiple handling ofheifers.

Some people may prefer naturalmating for heifers, especially if they donot have time to spend observing heatsand handling stock. Groups of heifers canbe run with the milking herd and either

Mating

In order to maximise the genetic gain inyour herd, your heifers should be mated tothe best bull you can find; the best way todo this is to use artificial insemination (AI).Heifers should be mated to easy calvingbulls.

To get the best results from AI yourheifers must be both at target live weightand increasing liveweight at mating.

Well grown heifers will begin to cycleearlier, will have stronger heats and willhave higher conception rates and fewercalving problems than poorly grownheifers. They also tend to have higher


3.6

mated with bulls or artificial insemination.For successful synchronisation you

must make sure that the heifers to be matedare cycling before the start of the program.There are a number of systems usedcommonly.

Progesterone implants

CIDR (controlled internal drugrelease). A progesterone-releasing implantis placed in the vagina. An oestradiolcapsule is also implanted at the same time(to remove any aged eggs). The CIDRimplant is removed 10 to 12 days later andthe cows are inseminated about 48 hourslater. A prostaglandin injection issometimes given on day 6.

Progestogen ear implants. Aprogesterone-releasing implant (such asSynchro-mate B®) is implanted in the ear,and an oestrogen–progesterone injection isgiven at the same time. The implant isremoved after 10 days, and the cows are

mated 48 hours later.These products work by lengthening

the oestrus cycle while they remainimplanted. When they are removed, theblood level of progesterone dropssuddenly and another egg begins todevelop—the cow begins to come intooestrus.

Prostaglandin injections

Two injections of prostaglandin (such asAfter weaning, calves should be allocatedto specific calf-raising paddocks.

Lutalyse® or Estrumate®) are given,generally 10–12 days apart.

For further information on managingheifers from weaning to calving, see theAgriculture Victoria Agnote AG0506,Health and mating management of heifersfrom weaning to calving; there is a copyof this publication in the FurtherInformation section of this manual.

Weaned calves should be allocated to specific calf-raising paddocks. Groups are basedon size to avoid ‘bullying’ around feed areas. Photo: J Irvine, Dungog.


4.1

* Heifers are returned to owner at 23 months to settle in to herd.

Contract rearing of dairy replacements

Table 4.1: Suggested target live weights

Introduction

Contract rearing of dairy replacementscan be an attractive option if you arerestricted by farm size and wish to milkmore cows. You can free up valuable land,labour and feed resources. You areguaranteed predetermined growth rates,with heifers ready to calve at 2 years andbig enough to maximise their geneticpotetial.

PaymentThe suggested method of payment is forweight gain and is loaded to favour goodearly growth to the target live weight forhigh fertility at mating. Suggested targetlive weights are given in Table 4.1.

Suggested payments

Weaning to mating: $1.00 per kg liveweight gain.

Mating to pre-calving: $1.10-$1.20 per kglive weight gain.

Payment schedules will vary fromrearer to rearer. Incentives may be paidfor agreed growth rates during wintermonths when supplements are likely to befed.

The average cost of rearing is $6.00 aweek, which includes payment for weightgain, health treatment, mating andweighing. Other costs would includetransport and preparation of legal contacts.

An overall minimum cost from 4 months to23 months would be $530 per heifer.

Drawing up contracts

Before you enter into an arrangement it isimportant that you draw up a detailedcontract with the rearer.

Some of the points that need to beincluded in this contract are:

• responsibility for—daily management—veterinary attention—mating and pregnancy

testing—delivery and collection

• date for delivery and collection

• weighing procedure and frequency

• payment schedule and timing of

payments

• penalties for not achieving the target

weight

• disease assurance programs

• penalties for deaths and losses.

Both parties must receive an adequatefinancial return to justify a contract rearingarrangement. From the owner’s viewpointthe return from running additional milkingcows must more than cover the costs ofcontract rearing. The contract rearer isinterested in the comparison betweenreturns from contract rearing and alternativeenterprises.


4.2

Other issues

Health and disease transfer

There is a potential for transferringdisease on to the rearer’s property orneighbouring farms if fences are notsecure. All stock (including those ownedby the rearer) should be tested negative orclear for EBL and Johne’s disease. Allbulls should be vaccinated for vibriosis.

Heifers should be vaccinated againstthe normal clostridial diseases andleptospirosis (give 7 in 1), as the latter canbe transferred to humans.

Mating heifers for year-roundcalving herds

Under year-round calving there will be aneed to mate a few heifers on a regularbasis. For the rearer this means constantlyjuggling bulls or using an AI program, asa large number of heifers may beinvolved.

Problems with contract growing arelikely to occur if the rearer and the ownerdo not fully understand the difficultiesassociated with heifer mating.


5.1

Make sure you attend to the welfare ofyour calves and heifers at all times. Belowis an extract from the Australian ModelCode of Practice for the Welfare ofAnimals (SCA 1992). It was compiled bythe Animal Health Committee of theStanding Committee on Agriculture.

3. Artificial Rearing of Calves

3.1 Housing for artificially reared calvesshould be hygienic, with adequateventilation, climate control andlighting. Flooring should be welldrained with adequate dry lying spacefor each calf. Flooring and internalsurfaces should not cause injury andshould allow easy cleaning.

3.2 Careful attention to group sizes,access to feed, milking shed location,ancillary accommodation, lighting, airinlets and outlets, handling facilitiesand stalls can alleviate problems ofhealth, stress or aggression.

3.3 For multiple calf rearing systems,where individual calf pens are used,these should be so made and locatedto allow each calf to see and hearother cattle (i.e. at least one otherindividual). 1.5 to 2.0 m2 of floor areaper calf should be provided to permitself-grooming and preventovercrowding. The total shed volumeshould provide for at least 5.5 m3 percalf.

3.4 In cold weather, adequate shelter orhousing, and feeds with a high energycontent should be provided.

3.5 Calves should receive at least twolitres of fresh or preserved colostrumor an approved substitute within thefirst 12 hours following birth.Thereafter, they should be fed on

liquid milk. commercial milk-replaceror colostrum, in sufficient quantitiesto provide essential requirements formaintenance and growth. High qualitypasture, hay or pellets should beavailable to calves from no later than3 weeks of age to help in developmentof their digestive tracts.

Hygienic calf feeding practices,including thorough daily cleansing ofall equipment (feeding units, lines,bottles, nipples, troughs, etc.) areessential to protect calf health andwelfare and to prevent diarrhoea.

3.6 Milk-replacers based on skim milkshould not be fed to calves under threeweeks of age, unless they are in aproperly balanced formulated mixtureof protein, fat and vitamins. Milkreplacers should be reconstitutedaccording to manufacturers’instructions. Milk and milk-replacersshould be reconstituted according tomanufacturers instructions. Milk andmilk-replacers should not be fed inexcess of body temperature (39oC).

3.7 Calves should be weaned off milk,milk replacer or colostrum on torations providing all essentialrequirements, only when theirruminant digestive systems havedeveloped sufficiently to enable themto maintain growth and well-beingand not earlier than 6 weeks of age.Restricted rations of the ‘white veal’type, i.e. iron-free diets which causeanaemia, are unacceptable.

3.8 Where large numbers of calves arereared, they should be grouped by ageand size to reduce competition forfood and to allow closer observationand management.

Animal welfare


5.2


6.1

Further information

Videos

Caring for Calves

Caring for Heifers

These commercially produced videos are

available from Brian Sullivan and Associ-

ates. Contact B Sullivan, Australian Dairy

Videos, 38 Range Street, Toowoomba,

Queensland 4350. Phone (076) 393 176.

Colostrum tester

Other

CalfGuard® is available from Northfield

Veterinary Laboratories, 180 Fosters

Road, Oakden, South Australia 5086.

Phone (08) 266 2266.

NSW Agriculture publications

Fulkerson, W (ed) 1996, NSW Agriculture

Dairy Research Institute Report, NSW

Agriculture 1996

Agnote 2/099 1996, Early weaning of

dairy calves

Agfact A1.2.2, Raising dairy calves

Agriculture Victoria publications

Agnote AG0501 1996, Comparing the

cost of supplements on the basis of their

nutritional value, Agriculture Victoria

Agnote AG0506 1997, Health and mating

management of heifers from weaning to

calving, Agriculture Victoria

Agnote AG0507 1997, Heifer nutrition

from weaning to first calving, Agriculture

Victoria

Agnote AG0503 1996, How to stomach

tube a calf, Agriculture Victoria

Agnote AG0578 1997, Nutritional scours

in milk-fed calves—causes and treatment,

Agriculture Victoria

General reading

Busby, G J, (ed)(undated), Dairy Heifer

Management, Information series QI

94021, Department of Primary Industries,

Queensland

Coomber, R & Phillips, K 1993, Cattle

Breeding and Reproduction, NSW Agri-

culture, 1997

Freeman, M 1993, ‘The Importance of

Liveweight’, in Your Heifers in the Bal-

ance, Department of Primary Industries

and Fisheries, Tasmania

Freeman, M & Campbell, R 1993,

‘Liveweight and Reproduction’, in Your

Heifers in the Balance, Department of

Primary Industry and Fisheries, Tasmania

Mason, W 1996, Best Practice Dairy Beef

Manual, Meat Research Corporation,

Sydney

McLean, D 1995, Current Australasian

Studies on Heifer Growth and its Effect on

Milk Production, Report for Dairy Re-

search and Development Corporation,

Primary Industries (South Australia),

Flaxley Agricultural Centre

McLean, D & Moran, J, eds (in press), A

Guide to Rearing Dairy Heifers in Aus-

tralia, Dairy Research and Development

Corporation, Melbourne

Moran, J 1993, Calf rearing—A Guide to

Rearing Calves in Australia, Department

of Agriculture Victoria, Agmedia, Mel-

bourne

SCA 1992, Australian Model Code of

Practice for the Welfare of Animals


6.2

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