Evaluation of the Criollo breed Romosinuano as purebred and crossbred cows with Brahman and Angus in Florida: I. Reproduction and parturition1,2,3

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 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 and 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 Brahman-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.

Genetic effects for reproductive performance of straightbred and crossbred Romosinuano and Angus cows in a temperate zone

“…This relative positioning of means in both experiments may highlight the more favorable performance of Romosinuano cows in a more temperate region; could it conversely suggest that Angus cows were more adapted to the conditions in Florida than in Arkansas? Such a notion, though not well supported, is intriguing given the background of the research Angus herd in Florida (Riley et al, 2007(Riley et al, , 2011(Riley et al, , 2014. In a subset of the purebred Angus and Romosinuano cows in this study, the Angus cows appeared to be more susceptible to the toxins in the tall fescue and heat stress during summer months than the Romosinuano cows (Burke et al, 2010).…”

“…The direct Romosinuano effects were favorable (Table 3; P o0.003). No breed type differences in calving and weaning rate were detected in evaluation of these groups and neither heterosis effects nor direct Romosinuano effects differed from 0 in Florida (Riley et al, 2014). This estimate of heterosis is at the upper range of values reported for Bos taurus cows (e.g., Cundiff et al, 1992;Newman et al, 1993) and was as high as many reported Bos indicus-British cross estimates (e.g., Cartwright et al, 1964;Prayaga, 2004).…”

“…No parameterization of cow age (P4 0.29) or breed type (P 40.65) was retained in the final model. Differences in calving interval in the Florida evaluation of these breeds were mostly related to Brahman straightbreds and crossbred groups and their differences from straightbred Romosinuano (Riley et al, 2014). Genetic effects previously reported for calving interval also involved Bos indicus crosses (Prayaga, 2004).…”

“…Year was influential for all traits and was retained in final models for each (Po0.05). This parameterization was different from evaluation of these breeds with Brahman in Florida (Riley et al, 2014), in which levels of age nested within year best modeled these 2 effects. A possible reason is the absence of 2-yr-old records in the present study; this result suggests that records from young ages are largely responsible for age effects of reproductive rates.…”

“…Heterosis expressed by Criollo crossbred cattle for reproduction was characterized in tropical or subtropical regions (Vergara et al, 2009;Riley et al, 2014), but has been investigated to only a limited extent in a temperate zone of the world (Corva et al, 1995), and the productivity of Criollo cattle on a harsh forage such as fescue has been characterized minimally (characteristics of milk; Burke et al, 2010). The objectives of this work were to: (1) estimate heterosis and breed direct effects for cow reproduction traits, (2) assess the effects of the type of forage grazed during the breeding season on those traits and on the estimates of heterosis and breed effects, and (3) characterize calf loss and cow removal by breed type.…”