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Dairy heifer nutrition

This Infosheet covers

• The post-weaning nutrition of heifers.

• Feed composition: energy, protein and dry matter levels.

• Balancing heifer diets to meet growth rate targets.

• Mineral requirements.

• Water requirements.

Key points

• Heifers are most feed efficient when they are young (small); try to capitalise on early growth efficiency.

• Nutrition pre-puberty (before 50% mature liveweight) influences skeletal growth.

• Growth rates give the best indication of whether heifers’ nutritional requirements are being met.

• Heifer diets need enough energy (10.5 MJ ME/kg DM or higher) and protein to achieve target growth rates.

Often pasture alone will be sufficient.

• Heifers require adequate mineral levels and available water.

Impact of age on nutritional requirements

• As heifers grow, their requirements change and the feeding levels and make-up of their diet should change as

well. Matching the type of feed, and its composition, to a heifer’s nutritional requirements is key to meeting

growth targets. There are three post-weaning nutritional stages:

• Weaning to nine months

This is a critical stage. Studies have identified that pre-puberty (before heifers reach 50% of their mature

liveweight) is when nutrition most affects skeletal growth1. Improved skeletal development will result in taller

heifers that suffer fewer problems at calving. It is important to stimulate lean body growth (muscle and skeleton)

without encouraging the deposition of excessive fat. This will increase a heifer’s frame size, as opposed to just

increasing body condition score.

For dairy animals typical to New Zealand2, growth rates from weaning of 0.7 kg/day in Holsteins and 0.5 kg/

day in Jerseys are required to achieve target weights. A diet high in energy and protein should be provided,

particularly as heifers’ rumen capacity may be limited during this stage (see Table 1).

To give heifers lush new pasture we do a cut of silage at the runoff before the calves go out.

Dairy farmer, 320 cows, Rerewhakaaitu, Bay of Plenty

We’ve had to look at our management over the first year of life. In the past heifers came home at

22 months and they were in good condition but not very well grown.

Dairy farmer, 320 cows, Hawera, Taranaki

FARMER VIEWPOINT


1Macdonald, KA, JW Penno, AM Bryant, and JR Roche. 2005. Effect of feeding level pre- and post-puberty and body weight at first calving on growth, milk production, and fertility in grazing dairy cows. Journal of Dairy Science. 88:3363-3375. 2DairyNZ 2016. Breed category averages. New Zealand Dairy Statistics. Page 32 3Handcock, RC, TJ Lopdell, LR McNaughton. 2016. More dairy heifers are achieving liveweight targets. Proceedings of the New Zealand Society of Animal Production. 76:3-7 4Based on calculations from Ian Brookes, Growing replacement heifers. Massey University, Palmerston North

Use heifer weights to see if heifers have been fed enough, we don’t measure feed intakes at the

runoff—we go off weight gain.

Dairy farmers, 265 cows, Inglewood, Taranaki

Putting weight on heifers in the autumn can be difficult. Even though our autumn grass looked like

rocket fuel, I started weighing and it showed the heifers weren’t gaining any weight. Sometimes the

dry matter is too low in the pasture.

Contract grazier, 850 heifers, Stratford, Taranki

• Nine months to mating at 15 months

During this period, heifers do not require a diet as high in energy and protein as younger heifers; however, they

require more feed to meet their maintenance and growth requirements. Heifers should have a progressively

increasing feed allocation, particularly when they are due to be mated.

• Older heifers

At this stage, a feed with a lower energy density can be used to maintain growth rates. Care should be taken in

the period coming up to calving. Attempting to make up for lost growth just before calving can result in overly

fat heifers (higher body condition) and/or overly large calves. Body condition reflects how well an animal has

been fed for the previous 6-8 weeks, whereas a longer period of good nutrition is required to convert feed into

body frame. New Zealand farm data3 indicates that heifers do not typically put on the necessary weight during

the autumn before their first calving; the cause of this is unknown.

Feed composition

Energy and protein requirements

All animals require energy for maintenance i.e. the energy required to sustain basic functions, such as normal metabolism,

and physical activities, including walking and eating. Growing animals also require energy for liveweight gain.

In New Zealand, the energy in a feed is expressed as megajoules of metabolisable energy per kilogram of dry matter

(MJ ME/kg DM).

As animals become heavier they become less efficient at using energy for growth. For example, a heifer weighing 100

kg requires about 20 MJ ME to gain a kilogramme of liveweight, whereas a 400 kg heifer requires double that i.e. 40

MJ ME (see Figure 14). Therefore, it is important to try to capitalise on energy efficiency when animals are young.

FARMER VIEWPOINT

We prioritize feeds by their protein content over the winter, the lighter animals get the higher

protein feeds. The lightest heifers are fed on all grass, the medium weight animals get turnips and

swedes, and the heaviest heifers get fodder beet.

Contract Grazier, 2,400 heifers, Mossburn, Southland

FARMER VIEWPOINT


Figure 1. Intake requirements of dairy heifers for a) maintenance only and b) for growth at different growth rates

(assuming feed energy value is 11 MJ ME/kg DM).

Current liveweight

100 kg

Maintenance intake

requirement =

1.6 kg DMday

Current liveweight

100 kg

Maintenance intake

requirement =

1.6 kg DMday

Calculating heifer intake requirements - example

Growth rate

0.6 kg/day

Growth intake requirement =

1.2 kg DM/day

Growth rate

0.6 kg/day

Growth intake requirement =

1.3 kg DM/day

Total intake required

1.6 + 1.2 =

2.8 kg DM/day

2.2 + 1.3 =

3.5 kg DM/day

The example shows how much heifers’ energy requirements change as they grow.

Monitoring heifer growth rates and comparing them with their expected weight gain will give a good indication if

the feeding programme is on track. Table 1 shows the energy and protein required at different liveweights for good

heifer rearing.

5

4

3

2

1

0

6

100 150 200 250 300 350 400 450 500

Current liveweight (kg)

Inta

ke (

kg D

M/h

a/d

ay)

1.62.2

Intake requirements for maintenance only

5

4

3

2

1

0100 150 200 250 300 350 400 450 500

Current liveweight (kg)

Inta

ke (

kg D

M/h

a/d

ay)

1.31.2

Intake requirements for growth only at different growth rates

0.4 kg/day 0.6 kg/day 0.8 kg/day 1.0 kg/day


Table 1. Energy and protein required by heifers of different liveweights, to meet their maintenance needs and target

growth rate.4

NB. Pregnancy energy requirements are not included.

Dry matter intake

Predicting the dry matter intake of dairy heifers is an important part of heifer rearing, but it can be difficult to

estimate because:

• Heifer dry matter intake as a percentage of liveweight decreases as liveweight increases, but the relationship is not direct.

• Dry matter intake is influenced by dietary fibre, but the influence decreases as liveweight increases—this is one of

the reasons that feeding high quality feed to young animals is so important.

Balancing diets to meet target growth rates

Grazed pasture is the cheapest feed source for growing cattle on most farms. If pasture quality is good enough i.e. 10.5

MJ ME/kg DM or higher, heifer growth rate targets can be met by using pasture alone, even with Kikuyu if it is leafy.

If pasture quality (due to excessive stem or dead material) or quantity (due to poor plant growing conditions) are

lacking, supplementation may be required to maintain heifer growth. Supplements should contain at least 11 MJ ME/

kg DM, and crude protein levels which are suitable for the animal’s nutritional stage.

Pasture characteristics required

To sustain high heifer growth rates, pasture should:

• be between 9 and 20 clicks on the plate meter, or

• 2500 on a sward stick, and

• contain at least 15% clover, and

• be predominantly made up of green and leafy material (low in stem and dead plant material).

Liveweight Energy Protein

Maintenance Growth rate per 1 kg

Kg MJ ME/day MJ ME/day %

100 19 17 17

150 26 24 17

200 32 28 17

250 37 29 15

300 42 31 15

350 47 39 14

400 51 40 14

450 55 40 14

500 62 40 14

550 69 40 14


Mineral requirements

Heifer mineral requirements should not be overlooked. These will vary due to various factors, including: forage

mineral levels, which will be affected by the soil type and fertiliser applications; supplementary feed utilisation;

and the interactions between minerals . For example, selenium deficiency can be an issue particularly on peat soils;

sodium may need to be supplemented when lucerne is fed; and as copper is bound by zinc, copper deficiency can

become an issue during the facial eczema season as zinc is used for control.

More information

• For more on heifer mineral requirements and treatment, see Heifer Infosheets: Trace Elements and Heifer

Infosheets: Trace Element Treatment.

• Further information is available in the Heifer Infosheet covering crops and supplements.

More information

• For more on use of a sward stick, see Beef + Lamb Fact Sheet Measuring Pasture Covers Using the Sward Stick (http://

beeflambnz.com/Documents/Farm/Measuring%20pasture%20covers%20using%20the%20sward%20stick.pdf).

With our paddock sizes we don’t put heifers in paddocks with pre-grazing covers greater than 2800,

I’d rather they go in to shorter feed than longer for feed quality.

Contract grazier, 150 heifers, Cheviot, Canterbury

To make sure we give heifers quality feed our grazing system doesn’t graze heifers in paddocks with

pasture covers greater than 2500 and we don’t graze harder than 1500. One of my clients went from

having 90% heifers below target before the system to 90% on or above target by using the system.

Grazing consultant, Winton, Southland

I think heifers need daily shifts so paddock subdivision needs to be small enough for the mob size.

Dairy farmer, 750 cows, Awanui, Northland

To make sure heifers are being offered quality feed on dryland pastures, we shift the heifers before

it looks like they need shifting.

Contract grazier, 720 heifers, Oamaru, North Otago

FARMER VIEWPOINT


More information

• For more on feed budgeting see DairyNZ Facts and Figures (https://www.dairynz.co.nz/media/2816711/

facts-and-figures-dairynz.pdf) and DairyNZ Farm Fact 3-21: Feed requirements for grazing dairy heifers

(https://www.dairynz.co.nz/media/3038271/feed-requirements-for-grazing-dairy-heifers-3-21-web.pdf).

• For more about feeding heifers see Heifer information: Dairy Heifer Nutrition.

Water requirements

Access to clean, fresh water is important for rumen function, metabolism and health. Inadequate levels will restrict heifer growth.

The water contained in feed will meet some of a heifer’s water requirements, but additional drinking water is essential.

Heifers require 3-6 litres water/kg DM eaten; the amount will vary depending on the air temperature5, the diet’s water

content, and mineral salt intake. During hot weather more water will be required to help regulate body temperature. Table

2 shows the expected water intakes of heifers of different liveweights at two different ambient temperatures6.

Table 2. Estimated water intake (litres/day) required by heifers, at two different ambient temperatures.

Air temperature (° C)

Liveweight (kg) 4 27

45 3 4

90 8 13

180 14 23

270 19 32

360 24 40

455 28 47

5Holmes, CW, IM Brookes, DJ Garrick, DDS Mackenzie, TJ Parkinson, and GF Wilson. 2007. Nutrition: Quantitative requirements of dairy cattle, Chapter 14. Milk Production From Pasture. Published: Massey University, Palmerston North. 6Heinrichs, AJ, LA Swartz. Management of dairy heifers. Penn State Extension circular 385. Pennsylvania State University, Old Main, State College, Pennsylvania. Available: http://extension.psu.edu/animals/dairy/nutrition/heifers