Jaimie Foxley
Vetlife Central Otago veterinarian
Preparing ewes for mating involves several key factors. Ewe body condition (BCS) is the major driver of ovulation and conception, while flushing and good trace element levels follow closely behind.
Hind body condition score (BCS) is critical to good milk production and early conception at mating. Hind BCS should be maintained around score 3.5 (BCS 3 being moderate and BCS 4 being fat).
Feeding before and after weaning is important. Ewes are primed to gain weight in late lactation, while removal of the energy demand from the lamb at weaning reduces the body’s incentive to gain condition.
Ewes below 3 at weaning should be offered better feed, and have any issues (worms, deficiencies, disease) identified and managed. Ewes that improve from BCS 2.5 to 3.5 could improve their conception by 6-10%. Ear tags to identify and remove repeat offenders are a good idea.
Ideally ewes will be between BCS 3 and 4 at ram introduction. Flushing these well-conditioned ewes at the same time can improve conception by another 5-10%.
Trace elements such as selenium, iodine and zinc are vital for ovulation, conception and survival of early embryos. Avoiding deficiencies is the first priority, but trials have shown additional levels of some minerals can have ‘bonus’ positive effects.
Long-acting formulations of selenium and iodine are effective ways of providing these trace elements before and during pregnancy. Selenium deficiency can cause foetal loss in early pregnancy, and then lamb survival and growth issues later. A single autumn injection of Selovin™ LA seems to provide enough to last the year.
Similarly, Flexidine™ injection provides over six months of iodine, so this covers all the way from conception to lambing.
Shorter-term boosts in minerals have been shown to improve conception, and Multimin® Copper Free, containing zinc, selenium and manganese, has been shown to improve conception rates in ewe flocks in both Australia and New Zealand. While the true mode of action is unclear, it is thought that its benefits occur from improving embryo survivability. That is, many ewes may conceive but lose their early embryo, whereas Multimin® Copper Free supports the retention of the fertilised embryo. It is most likely related to immune support, engendered by the combination of selenium, zinc and manganese.
Lamb prices are at record high levels, and the forecasts suggest they will stay that way for the near future. This is the year to maximise lamb production, hence maximise profitability. There are a number of tools that you can use to achieve this, and your Vetlife veterinarian will be happy to discuss these with you.
Always read and follow the label directions. Selovin™LA is registered pursuant to ACVM number A009509. Flexidine™ is registered pursuant to ACVM number A007866. Multimin® Copper Free is registered pursuant to ACVM number A009882.
