Cunningham, Samantha Fern (2005-08). Evaluation of F1 cows sired by Brahman, Boran, and Tuli for reproductive and maternal performance and cow longevity. Master's Thesis. Thesis uri icon

abstract

  • Birth (BW) (n = 1,107) and weaning weight (WW) (n = 1,024), pregnancy rate
    (PR) (n = 1,255), calf crop born (CCB) (n = 1,232), calf crop weaned (CCW) (n =
    1,225), and cow??s weight at palpation (CW) (n = 1,403) were evaluated from 1994 to
    2004 in 143 F1 females who were sired by Brahman (B), Boran (Bo), and Tuli (T) bulls
    and who were out of Angus and Hereford cows. In 2004, mouth scores (MS) (n = 71)
    were assigned to the remaining females. PR, CCB, CCW, CW, and BCS were evaluated
    using a model that consisted of sire of dam breed, dam of dam breed, and calf??s birth
    year/age of dam as fixed effects. Sire of dam within sire breed of dam and dam within
    sire of dam within sire breed of dam were used as random effects. BW and WW were
    analyzed using the same model including calf??s gender. Two-way interactions were
    tested for significance. Year/age was significant for all traits (P < 0.05). Adjusted
    means for BW for calves out of cows by B, Bo, and T sires were 35.66, 35.38, and 35.59
    kg respectively, and were not different (P > 0.05). Adjusted means for WW for calves
    out of cows by B, Bo, and T sires were 233.4, 220.1, and 208.2 kg respectively, and
    were significantly different. For both BW and WW, male calves were heavier (P < 0.05) than females. Adjusted means for PR for females sired by B, Bo, and T bulls were
    0.914, 0.945, and 0.920, and were not different (P > 0.05). Adjusted means for CCB for
    females sired by B, Bo, and T bulls were 0.890, 0.943, and 0.910 respectfully, and Bo
    was higher (P < 0.05) than B. CCW showed the same ranking as CCB with adjusted
    means of 0.834, 0.887, and 0.857 for cows by B, Bo, and T bulls, with Bo being higher
    (P < 0.05) than B. CW adjusted means, in the fall of 2002, were 594.29, 519.38, and
    517.3 kg. B-sired females were heavier (P < 0.05) than Bo- or T- sired cows. More Bo-
    (P = 0.013) and B-sired (P = 0.003) cows had solid mouths in 2004 than T-sired cows.

publication date

  • August 2005