Franklin Vets Blog

Heifer Synchrony – Reducing Bobby Calves

May 11, 2020

The use of heifer synchrony in a stock management program has a number of advantages – improving reproductive performance and longevity of your heifers, increasing the rate of genetic gain in your herd as well as reducing wastage into the bobby calf market.dairy cows

Synchronising heifers for AB mating ensures they are all up and running on day 1, giving them a greater chance of getting in calf early as well as more chances to get in calf. Early calving heifers result in early calving cows and a longer life in the herd.

Calves born to heifers make up the majority of calves entering the bobby calf market. With increasing social pressure on practices within the dairy industry this is a key area where improvements can be made which also aid in increasing productivity of the business. Heifer calves are genetically the best animals in the herd therefore using them to produce AB replacements allows you to keep the best produced by the best. Keeping replacement animals born to heifers also reduces the requirement for AI in the herd and allows the herd to be used to produce dairy beef cross animals for further income.

There are multiple options available for synchrony. Heifers that do not hold to the AI will all come back on in a narrow window and can either be bred naturally or artificially bred again to a detected heat. If using bulls, numbers should be doubled for the mob to ensure there are enough to cover every heifer in the short timeframe.

It is important to note that using heifer synchrony is not a useful tool to get heifers cycling year after year. Liveweight is the main determinant of puberty in dairy heifers and they need to be well grown and hitting targets in order to get the greatest benefit from the program and avoid negative flow-on effects on both milk production and reproductive performance. Synchronisation is a useful addition to a system already hitting rather than a quick fix for a youngstock rearing problem. Down to the numbers; Co-Synch and EcoSynch are the main options available for New Zealand Dairy Heifers. Both have been studied in New Zealand systems with similar results, reporting a conception rate of 52-54% to the first AI mating. In practice, results in the region of 65% are regularly achieved.

Heifer synchrony is an underutilised tool across many farms. Get in touch with your vet to have a chat about whether heifer synchrony is right for you.

Dr Leah Wakeford BVSc (Dist.)