Direct and maternal genetic effects due to the introduction of Bos taurus alleles into Brahman cattle in Florida: I. Reproduction and calf survival.

The objectives of this study were to assess the risk associated with proportion Brahman inheritance, cow age, dystocia, and birth date weather conditions on calf vigor at birth (n = 3,253) and preweaning mortality (n = 3,631), and to estimate heritabilities for these traits. Calves that had poor vigor at birth and calves that died before weaning were coded 1, and those that had adequate birth vigor or survived to weaning were coded 0. Traits were analyzed using GLM. Year (1951 to 2002), cow age, calfgender, minimum temperature on date of birth (two levels: < 5.6 degrees C; or > 5.6 degrees C), and occurrence of dystocia were main effects in models. The proportion of Brahman inheritance in calves was modeled as a covariate. Males had greater odds of poor birth vigor (odds ratio = 1.44, 95% confidence interval = 1.14 to 1.82). The odds of death before weaning for steers relative to heifers approached significance (P = 0.07; odds ratio 1.41, 95% confidence interval 0.97 to 2.04). Calves born to young (3-yr-old) or very old (13 yr or older) cows had greater (P < 0.05) odds of poor vigor and death before weaning than calves of 5-yr-old cows. Calves with difficult births had 2.59 times greater odds of poor birth vigor (95% confidence interval 1.40 to 4.79) and 12.9 times greater odds of death before weaning (95% confidence interval 8.14 to 20.39) than calves born with no dystocia. Calves born on days with minimum temperatures of 5.6 degrees C or less had greater odds of poor vigor (odds ratio 1.97, 95% confidence interval 1.50 to 2.59) and of death before weaning (odds ratio 1.64, 95% confidence interval 1.27 to 2.13) than did calves born on days with higher minimums. The occurrence of rainfall on date of birth did not influence calf vigor at birth or preweaning mortality (P > 0.85). Purebred Brahman calves had 24.7 times greater odds (95% confidence interval 8.23 to 73.97) of poor vigor than 2/3 Brahman calves. The regression coefficient estimate for fraction of Brahman inheritance approached significance (P = 0.07) for preweaning mortality. Estimates of direct and maternal heritability were 0.09 +/- 0.05 and 0.10 +/- 0.04 for birth vigor, and 0.06 +/- 0.05 and 0.09 +/- 0.04, respectively, for preweaning mortality. Some exploitable genetic variation exists for these traits, but management of other factors may yield more immediate improvement than selection.

Section: Brahman Inheritance Effectssupporting

confidence: 67%

Section: Cattlementioning

confidence: 99%

Genetic and nongenetic influences on vigor at birth and preweaning mortality of purebred and high percentage Brahman calves123

Riley¹,

Chase²,

Olson

et al. 2004

“…Significant heterosis was detected for cow weight at all times of record (Table 8). The estimate of heterosis for cow weight at weaning was similar in trait units and as a percentage of straightbred means (5.5%) to that reported previously for 6-yr-old cows (Riley et al, 2014) but lower than estimates for Bos indicus-British crosses (e.g., Olson et al, 1990). No heterosis for weight at the estimated time of first conception as heifers was detected for these breeds (Riley et al, 2010).…”

Section: Cow Weights and Changessupporting

confidence: 83%

Heterosis and direct effects for Charolais-sired calf weight and growth, cow weight and weight change, and ratios of cow and calf weights and weight changes across warm season lactation in Romosinuano, Angus, and F1 cows in Arkansas1

Riley

Burke

Chase

et al. 2016

The use of Brahman in cow-calf production offers some adaptation to the harsh characteristics of endophyte-infected tall fescue. Criollo breeds, such as the Romosinuano, may have similar adaptation. The objectives were to estimate genetic effects in Romosinuano, Angus, and crossbred cows for their weights, weights of their calves, and ratios (calf weight:cow weight and cow weight change:calf weight gain) across lactation and to assess the influence of forage on traits and estimates. Cows ( = 91) were bred to Charolais bulls after their second parity. Calves ( = 214) were born from 2006 to 2009. Cows and calves were weighed in early (April and June), mid- (July), and late lactation (August and October). Animal was a random effect in analyses of calf data; sire was random in analyses of cow records and ratios. Fixed effects investigated included calf age, calf sex, cow age-year combinations, sire breed of cow, dam breed of cow, and interactions. Subsequent analyses evaluated the effect of forage grazed: endophyte-free or endophyte-infected tall fescue. Estimates of maternal heterosis for calf weight ranged from 9.3 ± 4.3 to 15.4 ± 5.7 kg from mid-lactation through weaning ( < 0.05). Romosinuano direct effects (of the cow) were -6.8 ± 3.0 and -8.9 ± 4.2 kg for weights recorded in April and June. Calf weights and weight gains from birth were greater ( < 0.05) for calves of cows grazing endophyte-free tall fescue except in mid-summer. Cow weight change from April to each time was negative for Angus cows and lower ( < 0.05) than other groups. Cows grazing endophyte-free tall fescue were heavier ( < 0.05) at all times but had more weight loss in late lactation. Angus cows had the lowest ( < 0.05) ratios (negative) of cow weight change:calf weight gain, indicating an energy-deficit condition. Cows grazing endophyte-free tall fescue had more negative ( < 0.05) values for this trait but not in early lactation ( < 0.05). Estimates of heterosis ranged from 12.8 ± 9.5 to 28.6 ± 9.4 kg for cow weight, 7.9 ± 3.0 to 15.8 ± 5.0 kg for cow weight change, and 0.07 ± 0.03 to 0.27 ± 0.1 for cow weight change:calf weight gain. Direct Romosinuano effects ranged from 14.8 ± 4.2 to 49.8 ± 7.7 kg for cow weight change and 0.2 ± 0.04 to 0.51 ± 0.14 for cow weight change:calf weight gain. The adaptive ability of Romosinuano in temperate fescue regions may be favorable with respect to relative cow and calf weight but may be a consequence of lower milk-producing ability.

“…of Brahman-Bos taurus from other studies (0.09 to 0.10; Cartwright et al, 1964;Peacock and Koger, 1980;Prayaga, 2004). The Brahman-Angus estimate was more consistent with the upper range of those estimates but less than the value of 0.25 reported by Olson et al (1990). Brahman-Angus heterosis for calving rate was much larger (0.3) for cows grazing endophyte-infected tall fescue than that for bermudagrass (0.1; Brown et al, 2000).…”

Section: Calving and Weaning Ratementioning

confidence: 50%

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

Riley

Chase

Coleman

et al. 2014

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.