Farm Table says:
What is the problem?
The authors of this study wished to investigate the effect of sex, and genotype, on the growth rate of lambs. The effect of these two parameters was measured due to genotype having a large influence on lamb growth, and sex having a lesser influence, and the importance of maintaining genetic diversity in both pure and crossbred sheep.
What did the research involve?
The following breeds and crosses were used, 200 lambs from each genotype:
- Purebred: Pirot Pramenka (P) as genotype 1
- Wurtemberg (W) as genotype 2
- Crossbred F1 generation: Pirot x Wurtemberg (PxW) as genotype 3
- (Pirot x Wurtemberg) x Il de France (PxWxF) as genotype 4
Lambs had birth weight recorded and re-weighed every 30 days after. Birth weight (BWB), weight at the age of 30 days (BW30), 60 days (BW60) and at 90 days (BW90) were used for comparisons between genotypes. Feeding was ad-lib.
What were the key findings?
Male lambs were heavier at all time points, to female, across all genotypes. Genotype 4 showed the best growth performance. The highest birth weight (BWB) was for males of genotype 2 (W), with the lowest birth weight being the female lambs of genotype 1.
The authors surmise that the increased number of breeds in genotype 4 (3) indicate the importance of crossing sheep for genetic diversity.