Ewe Lambing Rate and Ram Selection Decision

Ram B is the better choice for this flock. The key argument is recorded performance and adaptation versus unrecorded size. Ram A's large frame is visually attractive but tells you nothing about fertility, lambing rate, mothering ability or survival, and a ram from a different region may be poorly adapted to communal grazing and open lambing. His high price is not matched by evidence of genetic merit. Ram B has the one piece of information that matters most for the farmer's goal: his dam produced twins in three consecutive years, which is direct evidence of reproductive performance in the same environment. His sire is known, which allows some prediction of his own performance and lets the farmer avoid close mating. A ram contributes half the genes to a large number of lambs, so choosing on recorded dam performance has far more impact than choosing on appearance. The practical caveat is inbreeding: Ram B shares a sire with some of the 20 replacement ewe lambs, so those must not be mated to him. The recommendation is to buy Ram B, use him over unrelated ewes, and keep the related ewe lambs for a different ram or for sale.

The first step is to separate the two failure points: ewes that did not conceive and lambs that died after birth have different causes. For the 12 dry ewes, check ram fertility and mating management - was the ram sound, was he with the ewes long enough, were ewes in adequate body condition at joining? Nutrition and flushing before mating strongly affect ovulation rate, and a mineral deficiency can raise early embryo loss. For the 8 lamb losses, check birth weight, lambing difficulty, weather at lambing, mothering behaviour and predator or mismothering risk in an open lambing system. Genetics matters most where the same ewes repeatedly fail or repeatedly lose lambs, or where a particular sire's progeny consistently show low survival. Records needed: ewe identity, mating dates and ram used, lambing date, number of lambs born and born alive, lamb birth weight where possible, cause of any loss, and ewe body condition at mating and lambing. With one year of data you can only describe the problem; two or three years let you identify repeat offenders. The action is to cull or treat repeat dry ewes, correct nutrition and ram management first, and only then select for lambing rate, so that management causes are not mistaken for genetic ones.

The 20 ewe lambs are the cheapest source of replacements, but their use must be planned around relatedness. Some are sired by the same ram that sired Ram B, so mating them to Ram B would be close inbreeding, which raises lamb mortality and reduces vigour - exactly the problems the farmer is trying to solve. The plan should therefore be: identify which ewe lambs are related to Ram B, using the farmer's knowledge of which ewes were served by which ram, and keep those ewe lambs for a different, unrelated ram. Ewe lambs should not be mated too young or too light; they should reach a target body weight and condition before joining, or they will lamb with difficulty and produce weak lambs. Keep records of each ewe lamb's dam and sire so future matings can be planned. If the farmer cannot trace parentage reliably, the safer course is to sell the related ewe lambs and buy in unrelated replacements, or to use a third ram. The overall aim is to build a flock with recorded performance while avoiding the slow, hidden cost of inbreeding.