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Genetic Parameters For Six Measures Of Length Of Productive Life And Three Measures Of Lifetime Production By 6 Yr After First Calving For Hereford Cows, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck
Genetic Parameters For Six Measures Of Length Of Productive Life And Three Measures Of Lifetime Production By 6 Yr After First Calving For Hereford Cows, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Genetic parameters for length of productive life given the opportunity (LPL|O), measured as days between first calving and disposal conditioned on one of six opportunity groups, L1 through L6 (e.g., L2 is length of productive life in days given the opportunity to live 2 yr after first calving), and lifetime production (LP), measured as the number of calves born (NB), number of calves weaned (NW), and cumulative weaning weight (CW) by 6 yr after first calving, were estimated using records of 1,886 Hereford cows from a selection experiment with three selected lines and a control line. Weaning weights were adjusted …
Number Of Calves Born, Number Of Calves Weaned, And Cumulative Weaning Weight As Measures Of Lifetime Production For Hereford Cows, G. E. Martinez, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck
Number Of Calves Born, Number Of Calves Weaned, And Cumulative Weaning Weight As Measures Of Lifetime Production For Hereford Cows, G. E. Martinez, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Genetic parameters for lifetime production for cows with the opportunity to produce from 2 through 7 yr of age, as measured by the number of calves born (NB2, …, NB7), the number of calves weaned (NW2, …, NW7), and cumulative weaning weight (CW2,…, CW7), were estimated using data from 3,064 Hereford cows from a selection experiment with a control line (CTL) and three lines selected for weaning weight (WWL), yearling weight (YWL), and an index of yearling weight and muscle score (IXL). Weaning weights were adjusted to 200 d of age and for sex and age of dam. Estimates of …
Genetic Response To Selection For Weaning Weight Or Yearling Weight Or Yearling Weight And Muscle Score In Hereford Cattle: Efficiency Of Gain, Growth, And Carcass Characteristics, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck
Genetic Response To Selection For Weaning Weight Or Yearling Weight Or Yearling Weight And Muscle Score In Hereford Cattle: Efficiency Of Gain, Growth, And Carcass Characteristics, R. M. Koch, L. V. Cundiff, K. E. Gregory, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
An experiment involving crosses among selection and control lines was conducted to partition direct and maternal additive genetic response to 20 yr of selection for 1) weaning weight, 2) yearling weight, and 3) index of yearling weight and muscle score. Selection response was evaluated for efficiency of gain, growth from birth through market weight, and carcass characteristics. Heritability and genetic correlations among traits were estimated using animal model analyses. Over a time-constant interval, selected lines were heavier, gained more weight, consumed more ME, and had more gain/ME than the control. Over a weight-constant interval, selected lines required fewer days, consumed …
Effect Of Organic Matter Addition To The Pen Surface And Pen Cleaning Frequency On Nitrogen Mass Balance In Open Feedlots, J. R. Adams, T. B. Farran, Galen Erickson, Terry Klopfenstein, C. N. Macken, C. B. Wilson
Effect Of Organic Matter Addition To The Pen Surface And Pen Cleaning Frequency On Nitrogen Mass Balance In Open Feedlots, J. R. Adams, T. B. Farran, Galen Erickson, Terry Klopfenstein, C. N. Macken, C. B. Wilson
Department of Animal Science: Faculty Publications
Three finishing trials were conducted to determine the effects of dietary manipulation and management on N losses from open feedlots. In each experiment, 96 steers were assigned randomly to 12 nutrient balance pens. In Trial 1, calves were fed for 180 d during the winter/spring months; in Trial 2, yearlings were fed for 132 d in the summer. In Trials 1 and 2, N losses from pens were compared directly by adding OM to the pen surface or indirectly by feeding digestible ingredients designed to increase OM excretion. The dietary treatment (BRAN) included 30% corn bran (DM basis) replacing dry-rolled …
Fat Supplementation And Reproduction In Beef Females, Richard N. Funston
Fat Supplementation And Reproduction In Beef Females, Richard N. Funston
Department of Animal Science: Faculty Publications
Inadequate dietary energy intake and poor body condition can negatively affect reproductive function. Supplemental lipids have been used to increase energy density of the diet and may also have direct positive effects on reproduction in beef cattle. Several fatty acid sources have been studied as they relate to reproductive function. Common sources include sunflower, safflower, cottonseed, rice bran, soybeans, fishmeal, animal tallow, and calcium salts of fatty acids. Fats have been fed before and after calving, during the breeding season, and during heifer development. Response to fat has been investigated through measuring body weight and body condition score, age at …
Review: Re-Evaluation Of Phosphorus Requirements And Phosphorus Retention Of Feedlot Cattle, H. C. Block, G. E. Erickson, T. J. Klopfenstein
Review: Re-Evaluation Of Phosphorus Requirements And Phosphorus Retention Of Feedlot Cattle, H. C. Block, G. E. Erickson, T. J. Klopfenstein
Department of Animal Science: Faculty Publications
Phosphorus requirement recommendations for cattle are important for preventing over-feeding of P and excessive P excretion. Improved precision in managing P nutrition can reduce feedlot waste management concerns. Current beef recommendations (NRC, 1996) fail to account for absorption coefficient variation related to P source, whereas dairy recommendations (NRC, 2001) change absorption coefficients with P source. Maintenance and BW gain requirements for absorbed P do not represent underlying relationships. Maintenance P requirements reflect endogenous P loss arising from failure to reabsorb salivary P. Basing maintenance requirements on saliva P secretion and re-absorption rates should improve precision of maintenance requirement estimates. Gain …
Comparisons Of Angus, Charolais, Galloway, Hereford, Longhorn, Nellore, Piedmontese, Salers, And Shorthorn Breeds For Weight, Weight Adjusted For Condition Score, Height, And Condition Score Of Cows, Jesus Arango, L. V. Cundiff, L. Dale Van Vleck
Comparisons Of Angus, Charolais, Galloway, Hereford, Longhorn, Nellore, Piedmontese, Salers, And Shorthorn Breeds For Weight, Weight Adjusted For Condition Score, Height, And Condition Score Of Cows, Jesus Arango, L. V. Cundiff, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Breed differences for weight (CW), height (CH), and condition score (CS) were estimated from records (n &#;&#;12,188) of 2- to 6-yr-old cows (n &#; 744) from Cycle IV of the U.S. Meat Animal Research Center’s Germplasm Evaluation (GPE) Program. Cows were produced from mating Angus and Hereford dams to Angus, Hereford, Charolais, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, and Salers sires. Samples of Angus and Hereford sires were 1) reference sires born from 1962 through 1970 and 2) 1980s sires born in 1980 through 1987. The mixed model included cow age, season of measurement and their interactions, year of birth, pregnancy-lactation …
Covariance Functions And Random Regression Models For Cow Weight In Beef Cattle, Jesus Arango, L. V. Cundiff, L. Dale Van Vleck
Covariance Functions And Random Regression Models For Cow Weight In Beef Cattle, Jesus Arango, L. V. Cundiff, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Data from the first four cycles of the Germplasm Evaluation program at the U.S. Meat Animal Research Center were used to evaluate weights of Angus, Hereford, and F1 cows produced by crosses of 22 sire and 2 dam (Angus and Hereford) breeds. Four weights per year were available for cows from 2 through 8 yr of age (AY) with age in months (AM). Weights (n &#;&#;61,798) were analyzed with REML using covariance function-random regression models (CF-RRM), with regression on orthogonal (Legendre) polynomials of AM. Models included fixed regression on AM and effects of cow line, age in years, season of …