Do you know how to select breeding stock for the future?

Selecting the right animals to retain in a flock influences labour demand, health, and overall productivity of a future flock.

While modern technology offers the potential to make life easier and improve decision-making, there are also low-tech approaches that can still take a flock forward.

The Hamilton's lamb 1400 head each year at Aikengall, comprising 700 Blackface ewes bred pure for replacements, with the remaining 700 Blackface ewes crossed Ref:RH070524130 Rob Haining / The Scottish Farmer...

Choosing the best and losing the rest

Improving the genetics of a flock involves continually removing the bottom end. Over time,these decisions may become stricter.

For instance, eradicating certain diseases (e.g. maedi visna (MV) or ovine pulmonary adenocarcinoma (OPA)) might be the first priority, even if it means tolerating undesirable traits temporarily to avoid excessive culling. Once the disease issue has been addressed, focus on the next trait based on the problems identified in the flock's context. Is it intervention too much at lambing time? Eliminating shearing costs? Is lameness a significant issue? Anything which requires substantial individual care and attention should be on the list to reduce. Balancing these priorities whilst also maintaining a replacement rate under 30% is challenging, necessitating prioritisation of key issues.

Identify the main offenders

Using a slaughter tag is a simple way to ensure undesirable genetics in the flock are not retained. For more nuanced issues, such as lameness or udder problems, mark animals with moderate issues to avoid retaining replacements from them. Coloured tags or using flag tags that can be notched can support a policy such as 'two strikes and you're out’.

Ewe lamb selection

Apply strict selection criteria based on the mother's performance and lamb growth rates. Lambs not well-grown (up to 20kg) by eight weeks of age are less likely to breed successfully. Monitor the twins and singles separately as lamb growth alone will favour singles. Keep 25% more ewe lambs than needed to allow for selection as they develop. After weaning, select against dirty bums, poor feet score, and low condition. If tupped as ewe lambs, scanning provides another selection opportunity for fertility, and poor condition at any stage in their development may warrant removal from the flock.

Tup selection

For any tups bred on the farm, keep more than required to allow for greater selection opportunities. These animals make up half the flock’s genetics, so rear them according to the standards you want for the entire flock. When buying rams, prioritise the breeder over the breed to ensure compatibility with the flock. Using estimated breeding values at this point can accelerate breeding progress.

The Hamilton brothers' flocks serve as a great demonstration of the traditional stratified system with a practical approach to selection. Heavy culling and high selection pressure needn't be complicated, but it can make your life easier.