In return, they will repay the investment through higher milk production and a longer productive life. A recent AHDB strategic farm webinar with Phil Kinch of Buscot Wick, explored how data can help decision making and maximise the performance of growing heifers with ruminant nutritional specialist, Hefin Richards. Host, Nic Parsons, AHDB's head of dairy development, recalls:
"The efficiency of heifer rearing can be determined by a number of factors. Average age at first calving is a good starting point, but it is also important to identify the percentage that fall within the target acceptable range. The average could be 24 months but there may be some animals calving very young to make up for animals which are calving much later. In a block-calving herd, like Phil's, the priority is to calve animals at the start of the block, so they will also be calving at the start of the block in two years' time. Reproductive performance is also critical to ensure most cows get in calf during the first three-week window. Using sexed semen on heifers and the earliest bred cows allows a greater number of heifer calves to be born earlier in the block.
"The danger of focusing on age at first calving is that sometimes performance can be compromised if the animals are not at target weight by first calving. This will have an impact on production and potentially survivability. Weighing heifers at key times allows you to identify strengths and weakness in the system. It's important to calculate the average daily live weight gain (DLWG) as this enables you to see if the system is predominantly on track, but knowing the range is also essential to recognise any animals that may need managing differently.
"The minimum target farmers should be aiming for is double the birth weight by weaning, but ideally this should be closer to 2.5x birth weight. By 12 months, the animal should be at 50% of its mature weight and 90% by calving. Achieving a good DLWG will have a big impact on lifetime performance. Focusing on health, nutrition and environment may have a higher cost per day but will lead to higher feed conversion efficiency (FCR) and lifetime gains," says Parsons.
Colostrum management is key to ensure calves get the best start in life, it is important to move onto a good quality calf milk replacer or milk and ensure adequate intakes. Post-weaning, it is crucial to maintain intakes of a good quality calf starter to maintain DLWG of at least 0.8 kg/day. Take every opportunity to regroup heifers according to size and performance when weighing. Investing in suitable weighing and recording software will enable you to identify areas to improve performance or reduce costs, helping improve management and efficiency across heifer rearing as well as milking herd performance.
You can find the key learnings, as well as the webinar recording and other resources at ahdb.org.uk/maximising-returns-from-growing-heifers