Evaluation of F1 Cows Sired by Brahman, Boran, and Tuli Bulls for Reproductive and Maternal Performance Traits and Cow Longevity

Birth (BWT) (n = 1,335) and weaning weight (WWT) (n = 1,246), pregnancy rate (PR) (n = 1,513), calf crop born (CCB) (n = 1,504), calf crop weaned (CCW) (n = 1,500), cow weight at palpation (CW) (n = 1,662), and cow body condition score (BCS) (n = 1,666) were evaluated from 1994 to 2010 in 143 F1 females sired by Brahman (B), Boran (Bo), and Tuli (T) bulls and out of Angus and Hereford cows. Mouth scores (MS) (n = 253) were assigned to the remaining cows from 2004 to 2009, excluding 2008. Pregnancy rate, CCB, CCW, CW, and BCS were evaluated using a model that consisted of sire of cow breed, dam of cow breed, and calf's birth year/age of cow as fixed effects. Cow within sire of cow within sire breed of cow and sire of cow within sire breed of cow were used as random effects. Birth weight and WWT were evaluated including sex of calf in the same model. Mouth scores were evaluated with two models. When broken and solid mouths were scored 1 and smooth 0, B- and Bo-sired cows (0.87 and 0.83) had higher scores (P < 0.05) than T-sired females (0.65). When solid mouths were scored 1 and smooth and broken scored 0, B-sired cows (0.40) were higher than T (0.07) (P < 0.05), and Bo (0.30) sired cows were not different from either (P > 0.05). The model for MS only included sire of cow breed and calf's birth year/age of cow as fixed effects. Two-way interactions were tested for significance. Calf's birth year/age of cow was important for all traits (P < 0.05) except the first MS model. Adjusted means (LSM) for BWT for calves out of cows by B, Bo, and T sires were 34.1, 34.0, and 34.1 kg respectively, and were not different from one another (P > 0.05). Least squares means for WWT for calves out of cows by B, Bo, and T sires were 236.7, 217.5, and 197.2 kg, respectively, and were significantly different. For both BWT and WWT, male calves were heavier (P < 0.05) than females, by 2.13 kg and 10.39 kg, on average. Least squares means for PR for females sired by B, Bo, and T bulls were 0.900, 0.930, and 0.912, and were not different (P > 0.05). Adjusted means for CCB for females sired by B, Bo, and T sires were 0.872, 0.944, and 0.892 respectively, and Bo was higher (P < 0.05) than B and T. Calf crop weaned ranked the same as CCB with adjusted means of 0.805, 0.894, and 0.843 for cows by B, Bo, and T bulls, with Bo being higher (P < 0.05) than B. Cow weight adjusted means for cows by B, Bo and T sires were 537.1, 468.9, and 462.6 kg, respectively, with B-sired females being heavier (P < 0.05) than both Bo and T sired cows. Body condition scores for B, Bo, and T sired cows were 5.19, 5.43, and 5.15, respectively, with Bo-sired cows being the highest (P < 0.05). Higher reproductive rates were found for Bo-sired cows, but B-sired cows weaned heavier calves.