Submitted to: Animal Genetics International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/7/2004
Publication Date: 9/11/2004
Citation: Casas, E., Lunstra, D.D., Stone, R.T. 2004. Quantitative trait loci for male reproductive traits in beef cattle. Proceedings 29th International Conference on Animal Genetics, September 11-16, 2004, Tokyo, Japan. p. 132.
Technical Abstract: The objective of the present study was to detect quantitative trait loci (QTL) for male reproductive traits. A Brahman x Hereford sire was mated to MARC III (1/4 Hereford, 1/4 Angus, 1/4 Red Poll, and 1/4 Pinzgauer) cows. Male offspring born in 1996 (n = 126) were castrated at 8.5 months of age and testicular traits were measured. Traits analyzed were concentration of FSH in blood at castration (FSH), paired testicular weight adjusted for age of dam (PTW), paired testicular volume adjusted for age of dam (PTV), calculated age at puberty (AGE), and body weight at castration (BYW). A putative QTL (expected number of false-positives < 1) was observed for FSH on chromosome (Chr) 5. The support interval for this QTL spans cM 47 to 82, where the maximum F-statistic was detected at 70 cM from the beginning of the linkage group. Animals inheriting the Hereford allele had a 2.47 ng/ml higher concentration of FSH in peripheral blood at castration than those inheriting the Brahman allele. Evidence also suggests the existence of a putative QTL on Chr 29 for PTW, PTV, AGE, and BYW. The maximum F-statistic was detected at cM 44 from the beginning of the linkage group for PTW, PTV, and AGE, and at cM 52 for BYW. The support intervals for PTW, PTV, AGE, and BYW spanned from cM 38 to cM 46, from cM 37 to cM 46, from cM 34 to cM 57, and from cM 37 to cM 59, respectively. Those animals that inherited the Brahman allele at this chromosomal region had a 45 g heavier PTW, a 42 cm**3 greater PTV, a 39 day younger AGE, and a 22.8 kg heavier BYW, compared to those inheriting the Hereford allele. Further studies need to be pursued to confirm the QTL for these traits in independent populations.