Amen, Tonya Sue (2004-12). Birth, weaning, carcass, and meat traits in Bos indicus-Bos taurus reciprocal backcross calves produced through embryo transfer. Master's Thesis. Thesis uri icon

abstract

  • Angus - Bos indicus (Brahman or Nellore) reciprocal backcross embryo transfer calves belonging to 28 full-sib families were evaluated for differences in birth weight (BW), gestation length (GL), weaning weight (WW), carcass weight (HCW), longissimus muscle area (REA), fat thickness (adjusted (ADJFAT) and actual(ACTFAT)), intramuscular fat (MARB), and Warner-Bratzler shear force tenderness (WBSF). Family types with a greater proportion of Bos indicus in the sire in relation to the amount in the dam (F1 x A and B x F1) averaged longer GL and heavier BW than their respective reciprocal crosses (A x F1 and F1 x B). Calves had longer GL when the F1 parent was BA as opposed to AB. Small differences (statistically insignificant) were detected for BW, but no consistent difference was found between offspring of AB and BA parental types, with the exception of male F1-sired calves. F1 x A and B x F1 crosses also showed a large BW difference between males and females (about 5.0 kg), while A x F1 and F1 x B crosses showed no BW difference between males and females. Further examination within each sex showed a difference between male reciprocals that was two times that of females. Calves with a higher percentage of Bos indicus in the sire compared to the proportion in the dam showed the same trend, as they were still heavier at weaning, and produced heavier carcasses than the reciprocal crosses, though these differences were not significant. As a whole, A backcross calves had more ACTFAT, more ADJFAT, larger REA, more MARB, and lower WBSF than B backcross calves, though no significant differences were detected between reciprocal crosses for any of these traits. These results suggest that for weight related traits, especially BW, both the breed constitution of the calf and the cross that produces the calf play an important role in its ultimate performance for Bos indicus crossbred calves. For carcass and meat related traits, it appears that the breed make-up of the calf itself is more significant in influencing performance than the cross used to produce the calf.
  • Angus - Bos indicus (Brahman or Nellore) reciprocal backcross embryo transfer

    calves belonging to 28 full-sib families were evaluated for differences in birth weight

    (BW), gestation length (GL), weaning weight (WW), carcass weight (HCW),

    longissimus muscle area (REA), fat thickness (adjusted (ADJFAT) and

    actual(ACTFAT)), intramuscular fat (MARB), and Warner-Bratzler shear force

    tenderness (WBSF).

    Family types with a greater proportion of Bos indicus in the sire in relation to the

    amount in the dam (F1 x A and B x F1) averaged longer GL and heavier BW than their

    respective reciprocal crosses (A x F1 and F1 x B). Calves had longer GL when the F1

    parent was BA as opposed to AB. Small differences (statistically insignificant) were

    detected for BW, but no consistent difference was found between offspring of AB and

    BA parental types, with the exception of male F1-sired calves.

    F1 x A and B x F1 crosses also showed a large BW difference between males and

    females (about 5.0 kg), while A x F1 and F1 x B crosses showed no BW difference

    between males and females. Further examination within each sex showed a difference

    between male reciprocals that was two times that of females.

    Calves with a higher percentage of Bos indicus in the sire compared to the

    proportion in the dam showed the same trend, as they were still heavier at weaning, and

    produced heavier carcasses than the reciprocal crosses, though these differences were

    not significant.

    As a whole, A backcross calves had more ACTFAT, more ADJFAT, larger REA,

    more MARB, and lower WBSF than B backcross calves, though no significant

    differences were detected between reciprocal crosses for any of these traits.

    These results suggest that for weight related traits, especially BW, both the breed

    constitution of the calf and the cross that produces the calf play an important role in its

    ultimate performance for Bos indicus crossbred calves. For carcass and meat related

    traits, it appears that the breed make-up of the calf itself is more significant in

    influencing performance than the cross used to produce the calf.

publication date

  • December 2004