21 Aug 2018
Calf nutrition on dairy farms: Unlocking genetic potential in heifers
Farmers that produce heifers from their best animals and invest in feeding them well in the milk feeding period will be rewarded with better long-term performance.
How you rear dairy heifers in the milk feeding period is key to unlocking their genetic potential and could have a huge impact on their lifetime performance, according to new research.
Three-and-a-half years into a five-year project (LifeStart) run by Trouw Nutrition in Holland, initial findings have found that feeding calves higher levels of milk solids in the rearing period has a direct carry-through into puberty and lactation.
Georgina Thomas, ruminant technical business manager for Trouw Nutrition, says the results highlight that maximising herd performance goes far beyond simply choosing the best genetics.
Instead, farmers need to focus as much on early nutrition as they do bull selection. She says: “We have this huge potential in pre-weaning period to manipulate the genetic expression of an animal. How we do that can have a big impact on metabolism, first lactation yields and survivability.”
The LifeStart project includes 86 heifer calves, split equally across two groups.
One group was fed 600g of milk solids per day, and the second, 1.2kg/day. All other feeding and management parameters were kept the same (see panel, below).
The results show a marked difference in long-term performance in those calves fed more milk (see graphic).
Miss Thomas says: “It shows it is well worth investing in the early period, but it also comes back to what you feed.
“You can only feed a higher level of quality milk replacer that has been carefully formulated.”
Higher feed rates will help boost daily liveweight gains, thus help heifers hit the target age of first calving of 24 months.
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Research Project
- 86 heifers in two groups
- Group 1: Fed 600g/head/day of milk solids across two litres fed twice daily
- Group 2: Fed 1.2kg/head/day of milk solids in four litres fed twice daily
- Calf milk replacer: LifeStart endorsed 50% skimmed milk, 24% protein, 20% fat
- Colostrum intakes, parity of dam and season of birth were all considered when grouping calves to reduce variability
- All provided with ad-lib water, starter feed and chopped straw
- Individually housed in hutches
- Weaned at 56 days old (step down weaned)
- Group housed from 70 days old and all treated the same
How to avoid compromising overall efficiencies
Am I maximising the potential of every pregnancy on-farm and am I rearing the number of heifers I actually need?
According to Emma Hutcheon, ruminant nutritionist and youngstock manager for Massey Feeds, these are some key questions all dairy farmers should be asking themselves.
In her experience, an upsurge in the use of sexed semen, plus improved conception rates on modern-day sexed products, means many farmers are rearing more heifers than they need, which could be actually compromising overall efficiencies.
She says: “If you put everything to sexed, you will get a bigger group of calves, so you have a bigger chance of disease. You have to bed them all down. If you have a smaller group of decent heifers, you can focus more on feeding them better to get them in-calf.”
It is not that Miss Hutcheons is against sexed semen; quite the opposite in fact. She believes conventional semen ‘does not have much of a place any more’ due to the 50% chance of producing a dairy bull calf with limited value.
Instead, she thinks the best breeding strategy lies around strategic use of sexed dairy semen on the best animals in the herd, followed by using sexed beef semen on the rest.
Higher value animals
This will result in higher value beef animals that will bring farmers a return from six to eight weeks of age.
She says: “That means you have enough money to buy one tonne of quality calf milk replacer and one tonne of concentrate to feed heifers well.”
She advises:
- Calculating the number of replacements you need based on culling rate, plus an extra 10% contingency, and serve that number to dairy sexed.
- Breed for longevity and fertility, along with other traits you need to improve in your herd.
- Put the rest to sexed beef semen.
- Alternatively, use a bull or triple beef semen, but understand you will get a 50:50 chance of a bull or heifer.
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