Inbreeding effects on postweaning production traits, conformation, and calving performance in Irish beef cattle

• Published in: Journal of animal science Vol. 86; no. 12; pp. 3338 - 3347
• Main Authors: Mc Parland, S, Kearney, J.F, MacHugh, D.E, Berry, D.P
• Format: Journal Article
• Language: English
• Published: Champaign, IL American Society of Animal Science 01.12.2008; Am Soc Animal Sci; Oxford University Press
• Subjects: Adipose Tissue; Adipose Tissue - metabolism; Agricultural practices; animal performance; Animal productions; Animals; Beef; Beef cattle; beef cows; Biological and medical sciences; body conformation; Body Constitution; Body Constitution - genetics; body fat; Body Weight; Body Weight - genetics; calves; calving; carcass quality; carcass weight; Cattle; cattle breeds; Cattle Diseases; Cattle Diseases - mortality; Commercial farms; Dystocia; Dystocia - veterinary; fecundity; Female; females; Food industries; Fundamental and applied biological sciences. Psychology; gender differences; genetic variation; genetics; heifers; Inbreeding; Ireland; Irish Republic; Linear Models; liveweight gain; Male; males; Meat and meat product industries; Meat processing; metabolism; Mortality; perinatal period; Physical growth; Pregnancy; purebreds; Reproduction; Reproduction - genetics; skeleton; Terrestrial animal productions; Twins; Vertebrates; veterinary; Weaning; Weight Gain; Weight Gain - genetics; Irish Republic; Ireland; calving performance; Inbreeding depression; Growth; Meat product; Calving; Carcass; Vertebrata; Mammalia; Production; Beef cattle; Inbreeding; Artiodactyla; Performance; Ungulata; Conformation
• ISSN: 0021-8812; 1525-3163; 1525-3163
• DOI: 10.2527/jas.2007-0751

The objective of this study was to quantify the effect of inbreeding on carcass quality, growth rate, live conformation measures, and calving performance in purebred populations of Charolais, Limousin, Simmental, Hereford, and Angus beef cattle using data from Irish commercial and pedigree herds. Variables analyzed are reflective of commercial farming practices. Inbreeding was included in a linear mixed model as either a class variable or a linear continuous variable. Nonlinear effects were nonsignificant across all traits. Inbred animals had decreased carcass weight and less carcass fat. The effects of inbreeding were more pronounced in the British beef breeds. Effects for carcass weight ranged from -0.87 kg (Charolais) to -1.90 kg (Hereford) per 1% increase in inbreeding. Inbred Charolais and Hereford animals were younger at slaughter by 3 and 5 d, respectively, per percentage of increase in inbreeding, whereas the effect of inbreeding on age at slaughter differed significantly with animal sex in the Limousin and Angus breeds. Inbred Limousin and Angus heifers were younger at slaughter by 5 and 7 d, respectively, per percentage of increase in inbreeding. Continental animals were more affected by inbreeding for live muscling and skeletal conformational measurements than the British breeds; inbred animals were smaller and narrower with poorer developed muscle. Calf inbreeding significantly affected perinatal mortality in Charolais, Simmental, and Hereford animals. The effects were dependent upon dam parity and calf sex; however, where significant, the association was always unfavorable. Dam inbreeding significantly affected perinatal mortality in Limousin and Hereford animals. Effects differed by parity in Limousins. Inbred first-parity Angus dams had a greater incidence of dystocia. Although the effects of inbreeding were some-times significant, they were small and are unlikely to make a large financial effect on commercial beef production in Ireland.