N.B. Simmons, M.L.Marks, J.A.Parish, S.T.Willard, T. Smith

The objectives of this study were to develop a method for evaluating hair shedding in beef cattle and determine its effects on cattle performance. Data were recorded on Angus (n=438), Charolais (n=70), and Hereford (n=38) females for 3 years over a 5-mo period every 28 days beginning in March and continuing through July. Animals were observed by trained technicians and given a numeric score of 1 to 5, with 1 referring to an animal that has shed its winter coat, and 5 referring to an animal with no signs of shedding. An average was obtained for each month to give five distinct scores over the course of the study. The mo in which a female had an average shedding score of < 3.5 was considered the mo of first shedding (MFS). Data were analyzed by using the mixed procedure in SAS with adjusted 205 day weight (d205wt) as the response variable and considered a trait of the dam with fixed effects of year, sex, location, MFS with a random effect of calf sire (n=62). All fixed effects except for location were significant except for MFS in Charolais and Hereford. In Angus cattle, dams with an MFS of March and April weaned calves 19.93 ± 9.92 and 18.833 ± 9.84 kg, respectively, heavier than dams with an MFS of July (P < 0.05). Weaned calves from dams with MFS of May, June, and July were not significantly different (P > 0.40). Phenotypic correlations were estimated on a small subsample of Angus dams (n=121). Data for hair characteristics included hair number and distribution for hair length which included percentage small (< 2 cm), medium (2 to 4 cm), and long (> 4 cm). Average visual hair score was positively correlated with hair number (0.11), percentage medium (0.73), and percentage long (0.36) and negatively correlated with percentage small (-0.80) distributions. Results indicate that hair shedding may play a role in decreased weaning weights when evaluated as a trait of the dam.

J. A. Parish, T. Smith, J. R. Parish, T. F. Best and J. T. Best

Reporting accurate calf birth weight (BW) is important for the calculation of BW and calving ease expected progeny differences. Birth weight information is used by many cow-calf producers in animal selection and culling decisions to minimize dystocia risk. The objectives of this study were to 1) evaluate different BW collection methods: visual appraisal, hoof circumference tape, spring scales, and digital scales and 2) determine if visual BW estimations change in accuracy as a calving season progresses. Birth weight measurements were collected on 587 spring- and fall-born purebred and crossbred calves located at the Mississippi Agricultural and Forestry Experiment Station Leveck Animal Research Center, Mississippi State, MS and Prairie Research Unit, Prairie, MS. Birth weight measurements were collected on each calf within the first 24 h after birth by visual appraisal, hoof circumference tape, spring scales, and digital scales during routine calf tagging and processing. Calf breed composition consisted of Angus (AN), Charolais (CH), and Hereford (HP=Polled Hereford, HH=Horned Hereford) purebred calves and crossbred calves sired by AN, HP, HH, Brangus (BN), Braford (BO) and Gelbvieh (GV) bulls. Least square means were estimated by using a GLM model that included sex, age of dam, calving season, timing of birth during the calving season, breed of calf, and BW method as independent effects with BW measurements as the response variable. Bulls were heavier at birth than heifers (P < .01), while spring-born calves were heavier than fall-born calves (P < .01). Charolais, HH, and HH- and BN-cross calves were the heaviest at birth, while calves sired by HP were the lightest (P < .05). Hoof tape estimates of BW were higher than measurements from digital scales and estimates from visual appraisals (P < .05). There was no significant difference (P > .15) between visual estimates and digital scale estimates from the beginning to the end of the calving season. These results suggest that BW estimates vary depending on the method being used and that inaccurate data could be submitted to breed associations for calculations of BW predictors.