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Influence Of Breed, Heterozygosity, And Disease Incidence On Estimates Of Variance Components Of Respiratory Disease In Preweaned Beef Calves, G. D. Snowder, L. Dale Van Vleck, L. V. Cundiff, G. L. Bennett
Influence Of Breed, Heterozygosity, And Disease Incidence On Estimates Of Variance Components Of Respiratory Disease In Preweaned Beef Calves, G. D. Snowder, L. Dale Van Vleck, L. V. Cundiff, G. L. Bennett
Department of Animal Science: Faculty Publications
The objective of this study was to characterize genetic and environmental factors influencing bovine respiratory disease (BRD) in beef cattle. Records from nine purebred and three composite breeds and a variety of F1 and three-way crosses, including the progeny of 12 additional different sire breeds produced over a 20-yr period (1983 to 2002), were evaluated for breed and heterozygosity effects on the observed incidence of BRD. Heterozygosity fractions for calves and dams were defined by generalized breed origins: British, Continental, and tropically adapted. Variance components were estimated for each pure and composite breed, and across all breeds and crossbreeds. The …
Genetic And Environmental Factors Associated With Incidence Of Infectious Bovine Keratoconjunctivitis In Preweaned Beef Calves, G. D. Snowder, L. Dale Van Vleck, L. V. Cundiff, G. L. Bennett
Genetic And Environmental Factors Associated With Incidence Of Infectious Bovine Keratoconjunctivitis In Preweaned Beef Calves, G. D. Snowder, L. Dale Van Vleck, L. V. Cundiff, G. L. Bennett
Department of Animal Science: Faculty Publications
Infectious bovine keratoconjunctivitis (IBK) is one of the most economically important diseases in preweaned calves. This study examined the health records of 45,497 calves over a 20-yr period to determine environmental and genetic factors influencing the incidence of IBK. Three data sets were analyzed with an animal model. The first data set (n = 41,986) evaluated environmental factors and genetic differences among nine purebred (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and three composite breeds (MARC I, MARC II, and MARC III). Weaning weights of calves diagnosed with IBK were 8.9 kg lighter (P < 0.05) than weights of healthy calves. Incidence of IBK was related to age of the calf and the seasonal life cycle of the face fly (Musca autumnalis …
Environmental Effects On Neonatal Mortality Of Beef Calves, S. M. Azzam, J. E. Kinder, Merlyn K. Nielsen, L. A. Werth, K. E. Gregory, Larry V. Cundiff, R. M. Koch
Environmental Effects On Neonatal Mortality Of Beef Calves, S. M. Azzam, J. E. Kinder, Merlyn K. Nielsen, L. A. Werth, K. E. Gregory, Larry V. Cundiff, R. M. Koch
Department of Animal Science: Faculty Publications
Calving records from 1969 to 1989 from the Roman L. Hruska U.S. Meat Animal Research Center were used to investigate how climatic conditions, in addition to dystocia, age of dam, size of calf, and sex affect calf survival from birth to 1 wk of age. Data were analyzed separately for cows calving with (n = 11,094) or without (n = 72,187) dystocia. Neonatal mortality was described by a logit model and parameters were estimated by maximum-likelihood procedures. Calves born to cows with dystocia were five times as likely to die neonatally than calves born without assistance. Of all calves that …
Estimates Of Genetic Parameters For Direct And Maternal Effects On Embryonic Survival In Swine, Luis T. Gama, Keith G. Boldman, Rodger K. Johnson
Estimates Of Genetic Parameters For Direct And Maternal Effects On Embryonic Survival In Swine, Luis T. Gama, Keith G. Boldman, Rodger K. Johnson
Department of Animal Science: Faculty Publications
Survival of 16,838 potential embryos was determined by counting corpora lutea and fetuses at 50 d of gestation for 1,081 litters by 225 sires. These data, coded as 1 or 0 depending on whether an ovulation was represented by a fetus, were used to estimate direct and maternal additive genetic variances and their covariance for embryonic survival. Data were from fist-parity gilts of a Large White-Landrace composite population subdivided into two lines, one selected for an index of ovulation rate and embryonic survival for seven generations and a contemporary control line. Variance components were obtained by ANOVA and expectations of …
Twinning In Cattle: 111. Effects Of Twinning On Dystocia, Reproductive Traits, Calf Survival, Calf Growth And Cow Productivity, K. E. Gregory, S. E. Echternkamp, G. E. Dickerson, Larry V. Cundiff, R. M. Koch, L. Dale Van Vleck
Twinning In Cattle: 111. Effects Of Twinning On Dystocia, Reproductive Traits, Calf Survival, Calf Growth And Cow Productivity, K. E. Gregory, S. E. Echternkamp, G. E. Dickerson, Larry V. Cundiff, R. M. Koch, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
An evaluation of natural twinning in beef cattle revealed that cows birthing twins had shorter (P < .0l) gestation lengths, more (P < .0l) retained placentas, more (P < .01) dystocia, more (P < .0l) days to estrus, lower (P < .0l) conception rates and more (P < .01) days to pregnancy than cows birthing singles. Days to estrus, conception rate and days to pregnancy were not affected by number of calves reared (1 vs 2) in cows birthing twins. Survival at birth was greater (P < .0l) for single- than for twin-born calves, but twins and singles did not differ (P > .05) in postnatal survival. When dystocia was experienced, calf survival at birth was 95% vs 73% for singles vs twins compared with 99% vs 92% when no dystocia was experienced. Calves born twins were lighter (P < .01) at birth, 100 d and 200 d, but twins and singles did not differ in postweaning gains. Total calf weights at 100 d per cow calving were 12% greater (P < .01) in cows birthing twins vs singles when twin calves reared by foster dams were! excluded. The potential increase in cow productivity for total calf weight at 100 d is 40% if calf survival rates of twins with dystocia relative to survival rates of twins without dystocia were comparable to survival rates of singles with and without dystocia, and if cows birthing twins were fed and managed to obtain conception rates equal to those of cows birthing singles. Identification of cows gestating twins to provide for their higher prepartum nutritive requirements and calving assistance at parturition is necessary to make twinning in cattle an economically viable technology.
Preweaning Survival In Swine: Heritability Of Direct And Maternal Effects, William R. Lamberson, R. K. Johnson
Preweaning Survival In Swine: Heritability Of Direct And Maternal Effects, William R. Lamberson, R. K. Johnson
Department of Animal Science: Faculty Publications
The heritabilities of direct and maternal effects on litter survival to weaning (LS) were estimated from records of 1,243 litters of pigs from the Nebraska Gene Pool population born from 1968 to 1981. Heritabilities were estimated by: (1) weighted least-squares regressions of average survival for litters of sons on average survival for litters of their sire, (2) nested analysis of variance with LS fitted to a model including year-line and sire of litter, (3) weighted least-squares regression of average survival for the litter of daughters on the survival of the litter of their dam and (4) nested analysis of variance …