|Riley, David - Former Ars Employee|
|Chase, Chadwick - Chad|
|Coleman, Samuel - Retired Ars Employee|
|Olson, Timothy - Retired Non Ars Employee|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2014
Publication Date: 5/1/2014
Publication URL: http://handle.nal.usda.gov/10113/58748
Citation: Riley, D.G., Chase, C.C., Coleman, S.W., Olson, T.A. 2014. Evaluation of the Criollo breed Romosinuano as purebred and crossbred cows with Brahman and Angus in Florida. I. Reproduction and parturition. Journal of Animal Science. 92(5):1902-1910. Interpretive Summary: Crossbreeding is an important strategy for the improvement of lowly heritable traits such as reproduction in beef cattle. Crossbreeding with the Brahman breed is advantageous in the Southern U.S. where heat and humidity depress performance of non-adapted cattle. Heterosis in Brahman-Bos taurus crossbreeding programs is large and beneficial for almost all traits of economic importance, and especially for traits related to cow reproduction and calf survival. There are Bos taurus cattle in Central and South America that have acquired some adaptation to extremes of the tropics. Embryos from the Colombian breed Romosinuano were used to establish a research herd in Brooksville, Florida. The overall objective of this research was to compare reproduction and parturition traits of the Criollo breed Romosinuano as straightbreds and crossbreds with Angus and Brahman in the subtropical Southern U.S., estimate heterosis, and direct and maternal genetic breed effects for traits related to cow reproduction and parturition. Cows (n = 404) were born from 2002 to 2005, and calving records (n = 1,484) from 2005 to 2011 were used to create calving and weaning rate, and calving interval (excluding the interval between 2 and 3 years of age), and calving interval limited to a maximum of 450 days. Heterosis estimates for Romosinuano-Brahman calving rate (0.06) and weaning (0.07) rate were statistically significant but about one-half the magnitude of Brahman-Angus (0.13 and 0.14, respectively). Direct effects of Brahman on calving and weaning rate were both negative, whereas, for Angus were positive. Maternal breed effects were of slightly lower magnitude and were positive for Brahman and negative for Angus. The effect of heterosis was to reduce calving interval -49.2 days for Romosinuano-Brahman and -37.2 days for Brahman-Angus (all records incuded). When calving interval records of 450 days or less were evaluated; however, Romosinuano-Brahman heterosis was -7.2 days. Romosinuano and cows sired by Romosinuano and out of Angus dams had the largest proportions of difficult births. Angus-sired crossbred cows and Brahman cows had the largest proportions of occurrence of udder problems. Breed groups of cows sired by Brahman had the largest proportions that died or were culled (0.1 to 0.28). For traits associated with reproduction and parturition in the subtropical U.S., Romosinuano-Brahman and Romosinuano-Angus cow performance was acceptable; however, heterosis was lower than with Brahman-Angus.
Technical Abstract: The objectives of this work were to compare reproduction and parturition traits of the Criollo breed Romosinuano as straightbred and crossbred cows with Angus and Brahman, to estimate heterosis and direct and maternal genetic breed effects, and to describe calf loss, cow removals from the project, the occurrence of calving difficulty, inadequate calf vigor at birth, and udder problems by cow breed groups. Cows (n = 404) were born from 2002 to 2005. After their first exposure to bulls as young cows, in all subsequent breeding seasons crossbred cows were bred to bulls of the third breed, and straightbred cows were bred to bulls of the other two breeds. Calving records (n = 1,484) from 2005 to 2011 were used to create calving rate and weaning rate and calving interval (excluding the interval between 2 and 3 yr of age). Final models for these traits included sire breed-dam breed interaction, cow age within year, and random animal effects. Heterosis estimates for Romosinuano-Brahman calving and weaning rate were 0.06 ± 0.02 and 0.07 ± 0.03 (P < 0.05); those for Brahman-Angus were twice as large (0.13 ± 0.03, 0.14 ± 0.03, respectively; P < 0.001). Estimates of Brahman direct effects on calving and weaning rate were –0.12 ± 0.04 and –0.14 ± 0.05 (P < 0.05); however, Angus direct effects were beneficial for both traits 0.1 ± 0.05 (P < 0.05). The effect of heterosis was to reduce calving interval by –49.2 ± 9.9 and –37.2 ± 9.7 d for Romosinuano-Brahman and Brahman-Angus, respectively (P < 0.001). Romosinuano and F1 cows sired by Romosinuano and out of Angus dams had the most occurrences of difficult births as a proportion of cows that calved (0.028 and 0.025; P = 0.04). Angus-sired crossbred cows and Brahman cows had the most occurrences of udder problems as a proportion of lactating cows (0.14 to 0.21; P < 0.04). There were more Braham-sired cows that died or were culled as a proportion of those cows that began the project (0.1 to 0.28, P <0.02) than cows in the other breed groups. Romosinuano-Brahman and Romosinuano-Angus cow performance was acceptable, but for most traits, those pairs of breeds had lower heterosis than Brahman-Angus.