A key influencer of next year’s performance. For Spring calving herds, the work of getting cows back in calf during October, strongly determines their performance in 2025 and these endeavours are either made easier or more difficult by a multitude of factors that precede this period.
Herd “performance” has a wide meaning. Many advisers discuss the additional revenue or dollars that come from having more cows calving earlier, but calving patterns also affect how complicated, or easy farm management will be in 2025 and whether you can exert greater selection pressure other than culling for infertility. And for those who are reducing GHG emissions per tonne of fat-and-protein-corrected milk, lifting reproduction efficiency is a key tool.
A stat that will give an early guide on how well this season will go, is the submission rate of cows in the first 3-week round of mating. At least 81% and ideally 90% of the herd should be put up for mating by the end of this first period. If your herd is below this threshold, please talk with us.
During the period leading to the mating start date and during mating itself, nutrition and body condition will significantly impact on the outcome.
Cows will stop losing body condition at about 6 weeks after calving (8 weeks for first calvers and cows older than 6 years), but only if good energy intakes are being maintained. The sooner the cow passes this point and starts gaining weight, the better her chance of having visible heats, and getting pregnant early.
Cows with a condition score of 4.0 or better at the start of mating get back in-calf more quickly and are less likely to be empty than those that are less than 4.0 when mating starts. Herds and cows that achieve high milk solid yields without excessive body condition loss in early lactation and achieve condition scores of 4.0 or better at the mating stat date, also have good reproductive performance.
As a guide, if 15% or more of the cows are below body condition score 4.0, or the herd average condition score dropped by more than 1.0 during early lactation it is worth talking with us on the costs and benefits of increasing feed supply to prevent any further losses in body condition.
A component of nutrition are trace elements; the critical ones being cobalt (Co), copper (Cu), iodine (I), selenium (Se) and zinc (Zn). Even for herds that have trace elements in the normal range, we routinely now recommend trace element supplementation using Multimin® or Multimin® Evolution by way of a subcutaneous injection 4 weeks prior to the start of mating.
Individual animals that are affected by disease since calving – mastitis, lameness, metabolic upsets – will perform poorly when it comes to getting back in calf or in more severe cases, they simply do not get pregnant.
To increase a herd’s 3-week submission rate, synchronisation of cows and heifers is a useful tactic. The purpose here is to synchronise the heats of animals that are already cycling, so they can be inseminated at the same time and within the first few days of the mating period.
Heat synchronisation allows efficient use of labour as the work of heat detection and AB is shortened into planned, intensive periods. It can be used to compress three cycles of breeding (9 weeks) into a 7-week mating programme, or two cycles (6 weeks) into a 4-week mating programme.
These programmes also help to increase heat detection rates in herds where less skilled staff are employed or where the herd manager’s time is limited. This is because people detecting heat can focus on the job for short, predicted periods.
There are a wide variety of programmes that can be considered and are best talked through with one of our farm production vets to ensure the outcome you are seeking, is achieved.