Dairy heifer performance and survival in the herd is a hot topic internationally, with good reason.
Heifers that reach their mature-liveweight-based growth targets have been seen to deliver both productive and reproductive benefits to the dairy farmer, helping to drive the bottom line on-farm
Recent LIC NZ research backs up previous studies and suggests that for every 1% closer to liveweight breeding value based targets heifers are at 22 months, farmers can expect close to 2 kg milk solids extra in the first and second lactation
It also showed that heifers that were 20% below their 22 month target had noticeably lower 3 week submission and 6 week in-calf rates.
It’s no surprise to most dairy farmers that poorly grown heifers generally struggle to survive and thrive in the herd. Historically this has been a problem area for New Zealand farmers
The good news is that farmers have taken up the challenge and are starting to make real gains in heifer growth
In recent years those that have been monitoring heifer growth through the first two years of life by weighing heifers and entering the liveweights into MINDA
® have shown significant gains.
On average their heifers are now achieving target liveweight at the key milestones of 6 and15 months.
While gains have also been made out to 22 months of age, there is still some way to go to meet the 22 month target. See Figure 1.
Are the targets realistic?
Yes, top performers are achieving target, as can be seen in the purple line in Figure 2.
On average overall, heifers achieved their live weight target at 6 and 15 months but failed to meet it at 22 months.
So what can farmers do to grow better heifers?
- Set the targets. Heifers should weigh the following percentages of expected mature liveweight at the listed ages
- 6 months of age – 30%
- 15 months of age - 60% ( key target at first mating milestone)
- 22 months of age – 90% ( key target for first calving milestone at 24 months)
How do I calculate expected mature liveweight?
- you can calculate this using sire information ( sire liveweight breeding values) and the dam liveweight information, or
- weigh your 5 year old cows of the same genetic mix in mid-lactation to determine expected mature liveweight and remember to correct it to a standardised body condition score of NZ 4.5.
- Weigh them 4-6 weekly to track growth.
- Manage heifers that are falling behind before they are more than 10% below target. New Zealand heifer growers have found that if heifers deviate off their target growth path by more than 10% it is very difficult to catch them up when relying on seasonal grass growth patterns alone.
- Make sure they hit puberty and get in calf quickly as yearlings, so they can calve down quickly in the herd. The closer they are to the key milestones of mating at 15 months or calving at 24 months, the closer to the target line they need to be.
- Once in the herd, manage them carefully so they can compete, get back in calf again quickly and deliver the benefits for a lifetime.
Get the best out of the genetics you purchase by growing your replacements to their breeding value based target liveweights and set them up for a productive and profitable life.
1. Handcock, R.C., Lopdell, T.J., McNaughton, L.R. 2016. More dairy heifers are achieving liveweight targets. Proceedings of the New Zealand Society of Animal Production, 76: 3-7
2. Burke, C., Blackwell, M. and S. Little ed. 2007. The InCalf book for New Zealand
dairy farmers. Hamilton, DairyNZ, p.42
3. Bryant, J.R., Holmes, C.W., Lopez-Villalobos, N., McNaughton, L. R., Brookes, I.M., Verkerk, G.A., Pryce, J.E. 2004. Use of breeding values for live weight to calculate individual targets for dairy heifers. Proceedings of the New Zealand Society of Animal Production, 64:118-121
4. McNaughton, L.R., Lopdell, T. 2012. Are dairy heifers achieving liveweight targets?. New Zealand Society of Animal Production, 72:120–122
5. McNaughton, L.R., Lopdell, T. 2013. Effect of heifer liveweight on calving pattern and milk production. Proceedings of the New Zealand Society of Animal Production, 73: 103-107
6. McNaughton, L.R., Voogt, J. 2013. Young stock – an investment that lasts a lifetime. Proceedings of South Island Dairy Event 4.3 http://side.org.nz/past-proceedings/