Maintaining correct nutrition for the mare is important to support fertility and immunity, giving her a better chance of conceiving first time and, potentially, reducing the need for repeat coverings. Research has shown that a rising plane of nutrition can benefit conception rates, which simply means that the mare should be improving in condition up to the point of covering. Mares who are significantly over or under weight are less likely to conceive and the aim should be for a body condition score of 5 - 5.5 (using the American system of 1 - 9).
As changes to a mare’s condition can take some time, dietary adjustments may need to be made several months in advance, whilst those coming out of work or competition will need to be well “let down” to stand a better chance of conceiving. Whether aiming for weight gain or loss prior to covering, the diet should be fully balanced to provide all the mare needs for good health and to build up nutrient reserves to support the planned pregnancy.
Sperm takes about 60 days to develop so raising the nutritional status of the stallion two months prior to his first covering, or collection if AI is being used, will help ensure that the sperm is at its optimum at the time of covering. The aim should be for the stallion to enter the breeding season with a similar body condition score to that described above for the mare and to be receiving a fully balanced diet supplying performance levels of vitamins and minerals to meet the increased demands of semen production and covering.