Maternal Matters: calving transition management
Body condition score (BCS) at calving is closely related to how quickly cows will start their reproductive cycles again after giving birth. Cows in the correct BCS at calving (2.5–3) tend to have a shorter interval to first heat and are likely to get back in calf more easily.
Nutrition around calving
By the time heifers approach calving, they should weigh 85% of their mature cow weight. This means growing at approximately 0.5 kg/day between breeding and calving.
Pre-calving nutrition is crucial to ensuring heifers breed successfully again within a 365-day period. Heifers have a naturally longer postpartum interval (time between calving and first oestrus) which is heavily influenced by body condition score.
Studies have shown that thin heifers have a 30-day longer postpartum interval than those heifers calving in good condition. This reduces rebreeding success because these thin heifers are often not cycling again before the start of the breeding season.
Thin heifers at calving are also more likely to encounter calving difficulties, resulting in an increased risk of calf mortality. Quality and quantity are also impacted.
The nutrient demands of heifers after calving are greater than those of a mature cow. This is because they are still growing, as well as maintaining themselves and lactating.
It is best to keep heifers separate from the main herd so that they can be given better quality grazing and avoid competition for feed with mature cows.
Heifers are prone to significant body condition loss during their first lactation. Post-calving, feed them well to minimise this loss of condition and encourage oestrus cycling before their second breeding season.
Thin heifers at weaning struggle to calve easily and conceive the following year. Early weaning can be useful in preventing this.