Growing great heifers
Having spent many years consulting with Dairy farmers, one area in which they commonly fall down is with growing their young stock.
Growing great heifers starts the day they are born, when they need to receive ample colostrum, good shelter, ventilation and a good calf rearing programme that will promote rumen development. Without the rumen growing quickly the calf is limited to milk as its only source of protein.
A revised group average live weight (LW) target (from NZGC analysis of records)
Better grown heifers reach and maintain critical targets earlier such as:
- Reach puberty earlier
- Conceive faster as yearlings and calve quicker as two-year olds
- Produce more milk in their first lactation and over their lifetimes
- Get back in calf as two-year olds
- Remain in herd well past their third lactation
To achieve these targets their diet needs to stimulate lean body growth without excessive fat deposition, this requires good sources of protein as well as energy. Top quality pasture is preferable to low grade grasses and roughage. Excessive energy over protein will mean greater fat deposits rather than mammary tissue development. Trace element levels are also essential to provide adequate growth rates.
Tendency in many rearing systems is to have heifers ‘fat' rather than ‘tall' - lack of/or poor-quality protein in diet. It is important to grow the skeleton quickly to improve the chances of achieving these targets.
After mating at 14 months of age they have the added requirement of growing the foetus as well as growing and maintaining condition. They need good quality food, especially protein content, with a high energy content. Ensure trace elements are adequate and be prepared to provide a good transition diet prior to calving.
Heifers at the time of calving need to have a body condition score of 5.5 and their body weight should be in the range of 450 - 550kgm. Stature or bone growth (as tall as the average cow in the herd) is vital. It is bone growth that requires the most energy input and requires both high quality protein and energy in their diet to achieve optimal growth.
The problem with the short fat heifer
A short fat heifer is still growing. Skeletal growth is very demanding on high-quality protein in diet and her milk production will be compromised. She is more prone to lameness (increased weight and smaller hooves), more likely to be empty and have a shorter life in the herd.
- They need high-quality food. Feed with high-quality pastures - do not send to run offs with native grasses of poor fertility and liming deficits.
- Supplement if necessary with quality feed.
- Debud as calves, rather than later.
- Drench with anthelmintics regularly - white drenches provide the broadest spectrum.
- Vaccinate for leptospirosis and clostridial infections.
- Ensure trace elements are adequate.