The objectives of these studies were (1) evaluate the relationship between
temperament, blood parameters, and performance in Brahman calves (n = 300); (2)
evaluate the relationship between residual feed intake (RFI) and reproductive
development in Brahman bulls (n = 41). Serum was collected at 24 h and d 21 to 24, and
analyzed for total protein (TP) immunoglobulin G (IgG), and cortisol (CS). Calves were
weighed at 24 h, weighed and evaluated for temperament using exit velocity (EV) at d
21 to 24, and at 28 d intervals thereafter. Beginning 28 d prior to weaning, and at 28 d
intervals through 56 d post-weaning calves were evaluated for pen score (PS) used to
calculate temperament score (TS = (EV+PS)/2). The average TS from 28 d prior to
weaning and weaning was used to generate temperament groups; calves 1 SD below the
mean being calm, those 1 SD above the mean being temperamental and all remaining
classified as intermediate. Calf TS influenced WW (P = 0.04) and ADG from birth to
weaning (P = 0.03). Serum TP at 24 h affected (P < 0.05) WW and ADG from birth to weaning. Serum IgG at 24 h affected (P = 0.03) WW. Brahman bulls (n = 41) were
evaluated for RFI, insulin-like growth factor I (IGF-I), temperament, reproductive
development, and ultrasound carcass traits. Serum was collected at d 0 and d 70 of the
feeding trial and analyzed for IGF-I. Bulls were classified as efficient, intermediate, or
inefficient (RFI classification method I) and as efficient or inefficient (RFI classification
method II). Bulls were evaluated for temperament at weaning using TS. Temperament
influenced (P < 0.05) IGF-I concentrations at d 0. Reproductive development was not
affected (P > 0.05) by TS. Residual feed intake classification did not influence (P >
0.05) age at reproductive milestones. Ultrasound carcass traits were not affected by TS
or RFI. Serum TP at 24 h was a viable indicator of future growth performance.
Temperamental animals had lower growth rates in both studies. Reproductive
development was not affected by RFI. BW at reproductive milestones was lower in
temperamental bulls.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2009-08-7147 |
| Date | 2009 August 1900 |
| Creators | Matheney, Kara J. |
| Contributors | Randel, Ronald D. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | application/pdf |
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