Good nutrition improves cow reproduction
Getting cows in calf on-time is one of the biggest profit drivers in New Zealand dairy farming. For seasonal calving herds, having cows calve early means more days in milk and fewer empty cows at the end of mating. One of the best ways to improve your herd’s reproductive performance is through good nutrition—before and after calving.
Body Condition is the starting point
Cows need to calve at the right Body Condition Score (BCS)—5.5 BCS for first and second calvers. For mature cows, it is between 5.0 to 5.5. After calving, they naturally lose condition. Aim to keep BCS loss to no more than 0.5 of a BCS. Losing more than 1 BCS before mating can delay cycling and reduce conception rates.
The most important time is from calving to mating. If cows are not getting enough energy, they go into negative energy balance affecting their hormones, delaying ovulation, and results in fewer cows cycling or getting in calf in the first three weeks.
Feeding energy is key
In early lactation, grass alone is often insufficient to meet the energy needs of high-producing cows. If pasture is short or of low quality, consider high-energy supplements like maize silage or high-energy feed blends to fill the gap and reduce body condition loss.
Keep an eye on pasture quality, too. Vegetative leafy grass with high Metabolisable Energy (ME) (11 to 12 MJ / kg DM) is best. Avoid overgrazing, which reduces intake and energy.
Watch protein
Adequate protein is required to drive milk production. Coming to the end of first round pasture can see poor pasture quality and crude protein levels as low as 12 to 14 percent in some areas. Then, in the second round of grazing, there is often an oversupply of protein. Perform an extended feed test on your pasture at key times of the season to make sure cows are receiving nutrients and meeting demand of production and reproduction.
Minerals Matter
Trace minerals like selenium, copper, and iodine play a big role in fertility. Low levels can cause early embryo loss. Test your cows and pastures regularly, and supplement based on results. Talk to your vet or nutritionist for a mineral plan that works for your farm.
Simple Strategies
- BCS regularly—especially before calving and mating.
- Feed well after calving—use supplements if pasture is insufficient to fully feed cows.
- Test your pasture—to ensure balance of protein and energy.
- Check mineral status—supplement where needed.
- Support early cycling—healthy cows cycle earlier and get in calf faster.
One of the best tools at your disposal is feeding your cows well. By managing BCS, energy intake, and mineral levels, you set your herd up for a productive season by getting more in calf early and reducing the number of empty cows come scanning time.
