Effects of Age at First Joining and Ewe Genotype on the Performance of Two-Tooth Ewes and That of Their Progeny to Slaughter

• Published in: Animals (Basel) Vol. 12; no. 5; p. 653
• Main Authors: Keady, Timothy W J, Hanrahan, James P
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04-03-2022; MDPI
• Subjects: Age; Age factors; Barley; Belclare; body condition score; body size; Body weight; Corn; Farms; Genotype & phenotype; Genotypes; grazing; Lamb; litter size; Nutrition; Pregnancy; Productivity; Progeny; Reproduction; Soybeans; Suffolk; Ultrasonic imaging; Weaning; Ireland; Belclare; grazing; Suffolk; body size; lamb; mortality; litter size; carcass weight; body condition score
• ISSN: 2076-2615; 2076-2615
• DOI: 10.3390/ani12050653

The effects of first-joining age (7 or 19 months) and genotype on ewe performance when joined to lamb at 2 years, and the performance of their progeny, were evaluated using 424 ewes, representing 3 genotypes: Belclare (Bel), Suffolk × Belclare (Suf × Bel) and Suffolk-type (≥75% Suffolk ancestry (Suf75)). Ewes were managed in a grass-based system. Ewes first joined at 7 months were lighter (p < 0.01) at 19 months and immediately post lambing; otherwise, age at first joining had no effects (p > 0.05) on ewes or their progeny and there were no important interactions with genotype. Bel and Suf × Bel had larger litters (p < 0.001) and reared more lambs per ewe joined (p < 0.01) than Suf75. Ewe genotype had no effect (p > 0.05) on proportion failing to lamb, incidence of lambing assistance, lamb mortality, ewe survival to 31 months, or progeny performance. Increasing the body weight of ewes at 7 months of age increased the probability (p < 0.02) of rearing 1 or more lambs at 2 years and there was no interaction with genotype. It is concluded that age at first joining had no negative impact on the performance of ewes or their progeny.