The period prior to mating heifers is one of those times when heifer performance becomes a key concern. While many factors affect heifer fertility, trace element evaluation is a critical area to consider.

Replacement heifers carry the genetic future of the herd and are vital to any farm. Achieving high conception rates in the first breeding season increases productivity.

Economic returns are also enhanced when heifers conceive well in their second mating season, which can be a challenging time.

Nutritional demands of heifers, including trace elements, during pregnancy can exceed that of mature cows because the heifer is partitioning nutrients for her own growth, for foetal development and, in the second breeding season, for lactation.

Deficiency of energy or protein for extended periods of time during the first 2½ years of life will have a negative impact on foetal development, calf viability, milk production, and rebreeding for the next pregnancy.

Dairy heifers on target to calve at the optimum 24 months have been shown to be more fertile and also to have similar improvements in fertility in the second breeding season compared to those calving at less than 26 months.

As these heifers are significantly more likely to survive in the herd beyond a third calving, they also spend significantly more days in milk, producing improved lifetime yields.

For beef heifers the optimum age at first calving is also two years; for spring-calving, grass-based suckler systems, delaying age at first calving from 24 to 36 months of age, is proven to reduce net margin per hectare by 50 per cent. Therefore, it is important that heifers reach their weaning, bulling and calving weight targets at the right age each season. Nutrition has crucial influence on achieving these targets (there is more information on the AHDB website for recommended targets).

Trace minerals are an essential component of a nutritional program for heifers and cows.

Copper is important for growth and in enzymes responsible for fertility and thrive.

Selenium is required for growth, immunity and fertility.

Cobalt is used by the rumen microbes to make vitamin B12, which is required in growth. Iodine is fundamental for thyroid hormones which are involved in metabolism and foetal development.

Trace element boluses

Beware of over-supplementing as there is a risk of causing toxicity with some trace elements. Deficiency should be diagnosed by a vet using blood and liver analyses to effectively confirm diagnoses.

Blood and liver analyses can also be used by your vet to monitor the efficacy of a feeding program. If deficiencies are diagnosed, then it is essential to find a suitable way of rectifying the imbalance.

One option is to consider an oral trace element bolus which delivers multiple trace elements over extended periods. Boluses are recognised as a prudent form of supplementation because of their slow-release formulation. However, every herd requires an individual approach to address each unique situation on-farm.