Montana State Univ. researchers evaluated health and performance records of 3637 calves from inbred and outbred populations over a 14-year period. The inbred cattle were linebred Herefords. The outbred cattle consisted of four genotypes: 1) Hereford; 2) Angus x Hereford; 3) Simmental x Hereford; and 4) Tarentaise x Hereford. Over the 14-year period, the average incidence of scours was 35%; the range was 13 to 64%. Incidence of scours was significantly higher for inbred than outbred calves (41 vs. 28%).
Incidence of scours was significantly higher in calves born to 2-yr-old dams and decreased with increasing age of dam. Scours significantly impacted calf weaning weight. Over all years, scouring calves weighed 458 lb at weaning while non-scouring calves weighed 478 lb. Also, outbred calves were significantly heavier than inbred calves (483 vs. 452 lb. The authors concluded that the economic benefit of managing to reduce the incidence of scours should exceed the expense to reduce the economic loss that can occur when calves are afflicted with scours.
Source: Montana State Ag Extension