Trial data shows heavier ewe lambs scan better

Meeting weight gain targets with ewe lambs can double their fertility performance, a Farming Connect trial has found.

Livestock farmer David Lewis of Halghton Farm, Bangor, hopes to lift ewe lamb conception rates from 60% to more than 85% after looking at the effect weight has on lamb fertility.  

The trial, which started in August 2019, has benchmarked ewe lamb conception rates according to weight.

See also: Guide to breeding from ewe lambs

Halghton Hall flock facts

  • 121ha grassland
  • 800 ewes lambed indoors
  • Scanning at 190% and selling 1.75
  • Lambs supplying Tesco cost of production contract at 20kg deadweight
  • Charolais and Limousin cattle finished at 18-23 months

Three separate weight groups were trialled; less than 41kg, 41-45kg and more than 45kg.

Lambs were marked according to weight and run in the same tupping group.

  • The heaviest lambs had a 98% scanning and a 76% conception rate
  • The middle group had a 62% scanning and a 49% conception rate
  • The lighter group had a 44% scanning and a 39% conception rate

Under the guidance of independent sheep expert Kate Phillips, Mr Lewis is aiming to grow lambs faster to reach target weights in time for tupping (see box below).

Last year’s ewe lambs achieved a conception rate of 57% in 2019.

Four tips to improve ewe lamb conception rates

  1. Target ewe lamb growth rates to match those of finishing lambs, either from quality grass or root crops.
  2. Ewe lambs need to reach 60-70% of their bodyweight to reach puberty, which is about 45kg for commercial lowland breeds.
  3. Prioritise the best grass to ewe lambs after weaning. Daily liveweight gains of 200-250g until six weeks after tupping may be necessary, so don’t just leave them on poor grazing on a hill.
  4. Single-born lambs may reach tupping weight faster, but they could scan lower genetically as they were singles.

Source: Kate Phillips