Open Access. Powered by Scholars. Published by Universities.®

Animal Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Department of Animal Science: Faculty Publications

Articles 901 - 930 of 1242

Full-Text Articles in Animal Sciences

Estimated Breeding Values For Meat Characteristics Of Crossbred Cattle With An Animal Mode1, L. Dale Van Vleck, A. F. Hakim, Larry V. Cundiff, R. M. Koch, J. D. Crouse, K. G. Boldman Aug 1991

Estimated Breeding Values For Meat Characteristics Of Crossbred Cattle With An Animal Mode1, L. Dale Van Vleck, A. F. Hakim, Larry V. Cundiff, R. M. Koch, J. D. Crouse, K. G. Boldman

Department of Animal Science: Faculty Publications

Longissimus muscle area, shear force measure, and sensory panel scores for flavor, juiciness, and tenderness, and marbling score were obtained from 682 steer carcasses, resulting from crosses among five Bos taurus and Bos indicus breeds. The single-trait model used included birth year and as covariates breed fractions, weaning age, and days on feed. The numerator relationship matrix was for 1,350 animals (682 steers, 74 pure breed and 52 F1-cross sires and 542 dams). The coefficient matrix was inverted to examine standard errors of prediction. Estimated breeding value is the sum of the estimate of genetic deviation and the weighted (fractions) …

Go to article

Direct Responses To Selection For Increased Litter Size, Decreased Age At Puberty, Or Random Selection Following Selection For Ovulation Rate In Swine, W. R. Lamberson, R. K. Johnson, D. R. Zimmerman, T. E. Long Aug 1991

Direct Responses To Selection For Increased Litter Size, Decreased Age At Puberty, Or Random Selection Following Selection For Ovulation Rate In Swine, W. R. Lamberson, R. K. Johnson, D. R. Zimmerman, T. E. Long

Department of Animal Science: Faculty Publications

Nine generations of selection for high ovulation rate were followed by two generations of random selection and then eight generations of selection for increased litter size at birth, decreased age at puberty, or continued random selection in the high ovulation rate line. A control line was maintained with random selection. Line means were regressed on generation number and on cumulative selection differentials to estimate responses to selection and realized heritabilities. Genetic parameters also were estimated by mixedmodel procedures, and genetic trends were estimated with an animal model. Response to selection for ovulation rate was about 3.7 eggs. Response in litter …

Go to article

Derivative-Free Restricted Maximum Likelihood Estimation In Animal Models With A Sparse Matrix Solver, K. G. Boldman, L. Dale Van Vleck Jun 1991

Derivative-Free Restricted Maximum Likelihood Estimation In Animal Models With A Sparse Matrix Solver, K. G. Boldman, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Estimation of (co)variance components by derivative-free REML requires repeated evaluation of the log-likelihood function of the data. Gaussian elimination of the augmented mixed model coefficient matrix is often used to evaluate the likelihood function, but it can be costly for animal models with large coefficient matrices. This study investigated the use of a direct sparse matrix solver to obtain the log-likelihood function. The sparse matrix package SPARSPAK was used to reorder the mixed model equations once and then repeatedly to solve the equations by Cholesky factorization to generate the terms required to calculate the likelihood. The animal model used for …

Go to article

Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp May 1991

Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp

Department of Animal Science: Faculty Publications

A genetic correlation near unity between ovulation rate in heifers and later twinning frequency led to consideration of using measures of ovulation rate in heifers for each estrous cycle, beginning at puberty, to increase accuracy of selection for twinning rate. An initial evaluation with a multiple trait animal model for predicting breeding values included six genetic groups: 1) selected Scandinavian bulls, 2) transfers from other populations at the Research Center to a twinning project, 3) early-purchased Holsteins, 4) late-purchased Holsteins, 5) early purchases-other breeds. and 6) late purchases-other breeds. For ovulation and twin measures, heritabilities of .l00 and .070 and …

Go to article

C. R. Henderson: Farm Boy, Athlete, And Scientist, L. Dale Van Vleck Jan 1991

C. R. Henderson: Farm Boy, Athlete, And Scientist, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Charles R. Henderson was proud to be a product of a farm in Page County, Iowa. He was a one man track team in Coin, Iowa, and a brilliant student. He became a world class competitor in track at Iowa State College and, at the same time, compiled a top academic record. His early experiences set the stage for the exceptional contributions of his animal breeding career, which did not begin until he was nearly 40 yr of age, but which spanned 40 yr when he was the acknowledged leader in development of statistical methodology applied to animal breeding. His …

Go to article

Use Of A Simulation Model To Evaluate The Influence Of Reproductive Performance And Management Decisions On Net Income In Beef Production, L. A. Werth, S. M. Azzam, Merlyn K. Nielsen, J. E. Kinder Jan 1991

Use Of A Simulation Model To Evaluate The Influence Of Reproductive Performance And Management Decisions On Net Income In Beef Production, L. A. Werth, S. M. Azzam, Merlyn K. Nielsen, J. E. Kinder

Department of Animal Science: Faculty Publications

A stochastic dynamic model of reproduction and a deterministic cow-herd economic simulation model were used to evaluate how management decisions and reproductive performance interact to influence net income in a cow-calf operation (1,000 cows) for 1 yr of production. The stochastic model was used to determine herd performance when length of breeding season (45, 70, or 120 d) interacted with three postpartum intervals of an estrus (48, 65, or 90 d) and three conception rates at first service (60, 70, or 80%). Short, moderate, and long postpartum intervals were used to reflect differences in reproductive performance. In addition, replacement heifers …

Go to article

Ovulation Rate And Twinning Rate In Cattle: Heritabilities And Genetic Correlation, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp Jan 1991

Ovulation Rate And Twinning Rate In Cattle: Heritabilities And Genetic Correlation, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp

Department of Animal Science: Faculty Publications

Repeated measures of ovulation rate on puberal heifers should be an effective way to select for increased twinning rate. A reliable estimate of the genetic correlation between ovulation and twinning rates is needed to implement such selection and to predict its efficiency. Restricted maximum likelihood was used to estimate genetic correlations from subsets of data collected from the twinning project at the Roman L. Hruska U.S. Meat Animal Research Center. The animal model included numerator relationships among the animals and 6x4 effects of year-season of measurement, age at measurement, and birth group. Genetic correlations between averages of ovulation rates for …

Go to article

Feeding Value Of Grain Sorghum For The Lactating Sow, G. F. Louis, A. J. Lewis, E. R. Peo, Jr. Jan 1991

Feeding Value Of Grain Sorghum For The Lactating Sow, G. F. Louis, A. J. Lewis, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

Two experiments were conducted to investigate the effects of a corn-soybean meal (CSBM) and a sorghum-soybean meal (S-SBM) diet on reproductive performance and nutrient utilization by sows. In Exp. 1,75 sows (39 gilts; 36 primiparous) were fed either a C-SBM or a S-SBM gestation diet from breeding to d 109, On d 110, sows were assigned to lactation diets; half of the sows from each dietary treatment were assigned to a lactation diet based on the opposite grain. Sow weight change from d 54 to farrowing was greater (P < .06) for sows fed S-SBM than for sows fed C-SBM. There was no difference (P > SO) in weight change of sows during lactation. Feed consumption during …

Go to article

Gonadotrophin Concentrations And Ovulation Rates In Suffolk Ewes Actively Or Passively Immunized Against Inhibin Alpha, B. D. Schanbacher, S. R. Schemm, S. M. Rhind Jan 1991

Gonadotrophin Concentrations And Ovulation Rates In Suffolk Ewes Actively Or Passively Immunized Against Inhibin Alpha, B. D. Schanbacher, S. R. Schemm, S. M. Rhind

Department of Animal Science: Faculty Publications

Mature Suffolk ewes were either actively or passively immunized against the synthetic fragment of porcine inhibin alpha, pIα(1-30),to determine the effects on gonadotrophin secretion and ovulation rate. Thirteen control ewes were immunized against human serum albumin, 12 ewes were actively immunized against pIα(1-30)and 36 ewes were passively immunized with pIα(1-30)antiserum. Blood samples were collected at 4-h intervals for 72 h from oestrus-synchronized ewes following the withdrawal of the progestagen pessaries. Mean gonadotrophin concentrations measured during the oestrous cycle of control ewes, ewes actively immunized against pIα(1-30) and ewes passively immunized against pIα(1-30)were similar, but their secretory profiles differed. Serum concentrations …

Go to article

Genotype By Environment Interaction For Holstein Milk Yield In Colombia, Mexico, And Puerto Rico, T. L. Stanton, R. W. Blake, R. L. Quaas, L. Dale Van Vleck, M. J. Carabano Jan 1991

Genotype By Environment Interaction For Holstein Milk Yield In Colombia, Mexico, And Puerto Rico, T. L. Stanton, R. W. Blake, R. L. Quaas, L. Dale Van Vleck, M. J. Carabano

Department of Animal Science: Faculty Publications

Components of (co)variance and genetic parameters were estimated by REML procedures from first lactation mature equivalent Holstein milk records from 54,604 Colombian, Mexican, and Puerto Rican cows and 198,079 US cows. The objective was to determine the cause of heterogeneous daughter response to sire selection for milk yield between the regions. Data from Latin America were partitioned by country and by herd-year SD class for milk to obtain five joint analyses between the US and Latin America, low herd-year SD, high herd year SD, Colombia, and Mexico. Sire and residual variances for milk were 41 and 29% smaller in Latin …

Go to article

Effects Of Trenbolone Acetate On Carcass Characteristics And Serum Testosterone And Cortisol Concentrations In Bulls And Steers On Different Management And Implant Schemes, Steven J. Jones, R. D. Johnson, Chris R. Calkins, M. Dikeman Jan 1991

Effects Of Trenbolone Acetate On Carcass Characteristics And Serum Testosterone And Cortisol Concentrations In Bulls And Steers On Different Management And Implant Schemes, Steven J. Jones, R. D. Johnson, Chris R. Calkins, M. Dikeman

Department of Animal Science: Faculty Publications

The objective of this study was to determine the effects of different implanting schemes on serum testosterone and cortisol concentrations, and carcass traits of bulls and steers implanted with trenbolone acetate (TBA) and zeranol (Z). Twenty Polled Hereford bulls were randomly assigned to one of three treatments after birth. Five calves served as nonimplanted control bulls (NIB). Nine bulls were implanted (IB) with 140 mg of TBA and 36 mg of Z at about 1 mo of age and reimplanted with both compounds 10 wk later. When IB calves were about 21 wk of age, the TBA implant was removed …

Go to article

The Effect Of Cimaterol And Its Withdrawal On Carcass Composition And Meat Tenderness Of Broiler Chickens, B. L. Gwartney, Chris R. Calkins, Steven J. Jones Jan 1991

The Effect Of Cimaterol And Its Withdrawal On Carcass Composition And Meat Tenderness Of Broiler Chickens, B. L. Gwartney, Chris R. Calkins, Steven J. Jones

Department of Animal Science: Faculty Publications

To examine the effects of cimaterol (CIM) and its withdrawal on meat tenderness and carcass composition, 214-old broiler chickens (n = 288) were randomly assigned to one of nine treatments. For Treatments 1 through 6, bids were fed a control diet or a diet containing 1 ppm CIM until slaughter at 35, 42, or 49 d of age. Treatments 7 and 8 consisted of birds fed the CIM diet for 14 d and then withdrawn from CIM for either 7 or 14 d before slaughter (42 or 49 d of age). In Treatment 9, birds were fed the CIM diet …

Go to article

Amino Acid And Energy Interrelationships In Pigs Weighing 20 To 50 Kilograms: Weight And Efficiency Of Weight Gain, L. I. Chiba, A. J. Lewis, E. R. Peo, Jr. Jan 1991

Amino Acid And Energy Interrelationships In Pigs Weighing 20 To 50 Kilograms: Weight And Efficiency Of Weight Gain, L. I. Chiba, A. J. Lewis, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

The relationships between dietary amino acids and DE for pigs weighing 20 to 50 kg were investigated in two experiments

Go to article

Amino Acid And Energy Interrelationships In Pigs Weighing From 20 To 50 Kilograms: Rate And Efficiency Of Protein And Fat Deposition, L. I. Chiba, A. J. Lewis, E. R. Peo, Jr. Jan 1991

Amino Acid And Energy Interrelationships In Pigs Weighing From 20 To 50 Kilograms: Rate And Efficiency Of Protein And Fat Deposition, L. I. Chiba, A. J. Lewis, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

Two experiments were conducted to investigate the relationships between amino acids and DE for pigs weighing 20 to 50 kg. In Exp. 1, there were three dietary lysine levels that were either adjusted (1.50, 2.35 and 3.20 g/Mcal DE) for five DE levels (3.00 to 4.00 Mcal/kg) or unadjusted (.45, .71 and .%% of the diet) for three DE levels (3.50 to 4.00 Mcal/kg). In Exp. 2, diets containing six 1ysine:DE ratios (1.90 to 3.90 g/Mcal) at two DE levels (3.25 and 3.75 Mcal/kg) were fed. Pigs were housed individuiiy, and could eat and drink ad libitum. When pigs weighed …

Go to article

Effects Of Breeding Season Length And Calving Season On Range Beef Cow Productivity, Gene H. Deutscher, J. A. Stotts, Merlyn K. Nielsen Jan 1991

Effects Of Breeding Season Length And Calving Season On Range Beef Cow Productivity, Gene H. Deutscher, J. A. Stotts, Merlyn K. Nielsen

Department of Animal Science: Faculty Publications

A 5-yr study was conducted beginning in 1983 with 460 cows to evaluate the effects of three breeding seasons (30,45, and 70 d in length) and two times of spring calving, March (early) and April (late), on cattle production under Nebraska Sandhills range conditions. Criteria evaluated included pregnancy and weaning percentages, calving date and distribution, cow weights and body condition at four intervals, calf birth and weaning weights, and cow productivity. The 30-d breeding season included a 10-d estrus synchronization and AI period; in the other breeding seasons only natural breeding was used. The same sires were used over the …

Go to article

Distribution Of Time To First Postpartum Estrus In Beef Cattle, S. M. Azzam, L. A. Werth, J. E. Kinder, Merlyn K. Nielsen Jan 1991

Distribution Of Time To First Postpartum Estrus In Beef Cattle, S. M. Azzam, L. A. Werth, J. E. Kinder, Merlyn K. Nielsen

Department of Animal Science: Faculty Publications

The function of a distribution that describes postpartum interval (PPI) under any experimental treatment is useful for simulation modeling, understanding the effects of stimuli on the endocrine system, and estimating the average PPI in experiments terminated before all animals have expressed estrus. This study was undertaken to compare the fit of three statistical distributions, the Weibull, the log-normal, and the linear hazard rate (LHR), to the empirical distribution of PPI for five treatment regimens: no bull exposure postpartum, bull exposure from 53 d postpartum, bull exposure from 3 d postpartum, and bull exposure from an average of 63 d postpartum …

Go to article

Estimates Of Genetic Selection Differentials And Generation Intervals For Four Paths Of Selection, C. P. Van Tassell, L. Dale Van Vleck Jan 1991

Estimates Of Genetic Selection Differentials And Generation Intervals For Four Paths Of Selection, C. P. Van Tassell, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Estimated genetic values from an animal model based on first lactation milk records for 6OOO AI Holstein sires and 1,074,971 Holstein cows born in 1981 or before were used to estimate average genetic selection differentials and generation intervals for the four paths of selection for each year of birth. Selection differentials for paths of sires of bulls, dams of bulls, sires of cows, and dams of cows averaged over all years were 405, 395, 239, and 42 kg and for the most recent 5 yr 884, 598, 235, and 28 kg. Generation intervals averaged for all years were by path …

Go to article

Heritability Estimates Of Transformations Of Normally Distributed Records, A. L. Destefano, L. Dale Van Vleck Jan 1991

Heritability Estimates Of Transformations Of Normally Distributed Records, A. L. Destefano, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Milk yields were simulated for identical twin and parent-progeny pairs to determine effect of transformations on genetic variance. Use of identical twin pairs excludes variability due to Mendelian sampling and contribution by the other parent present in parent-progeny records. Phenotypic variances of 616,800; 1,439,200, and 2,261,600 and means from 2267 to 13,603 by increments of 2267 were used for linear scale records. Phenotypic variances of .0100O, .01875, and .02750 and means equal to the natural logarithm of the means for linear scale were used for log scale records. Heritability varied from .05 to .95 by increments of .lo. For each …

Go to article

Influence Of Growth Rate And Exposure To Bulls On Age At Puberty In Beef Heifers, M. S. Roberson, M. W. Wolfe, T. T. Stumpf, L. A. Werth, Andrea S. Cupp, N. Kojima, P. L. Wolfe, Roger J. Kittok, J. E. Kinder Jan 1991

Influence Of Growth Rate And Exposure To Bulls On Age At Puberty In Beef Heifers, M. S. Roberson, M. W. Wolfe, T. T. Stumpf, L. A. Werth, Andrea S. Cupp, N. Kojima, P. L. Wolfe, Roger J. Kittok, J. E. Kinder

Department of Animal Science: Faculty Publications

Two experiments were conducted to test the following hypotheses: 1) exposure of beef heifers to sterile bulls increases the proportion of heifers attaining puberty by 14 mo of age and 2) rate of growth interacts with bull exposure to influence age at puberty in beef heifers. In Exp. I, heifers were assigned to one of two treatments: 1) heifers were exposed to bulls (BE approximately 70-d period of exposure) or 2) heifers were isolated from bulls (NE) and served as controls. In Exp. 11, heifers were assigned to either BE or NE treatments (175-d period of exposure to bulls) and …

Go to article

Effects Of Errors In Pedigree On Three Methods Of Estimating Breeding Value For Litter Size, Backfat And Average Daily Gain In Swine, T. E. Long, R. K. Johnson, J. W. Keele Dec 1990

Effects Of Errors In Pedigree On Three Methods Of Estimating Breeding Value For Litter Size, Backfat And Average Daily Gain In Swine, T. E. Long, R. K. Johnson, J. W. Keele

Department of Animal Science: Faculty Publications

Estimated breeding value (EBV) was calculated based on either individual phenotype (SP), an index of individual phenotype and full- and half-sib family averages (SI) or Best Linear Unbiased Prediction (BLUP). Calculations were done with correct data or data with 5, 10, 15 or 20% of the records per generation containing pedigree errors. Traits considered were litter size (LS), backfat (BF) and average daily gain (ADG). When data were correct, BLUP resulted in an advantage in expected genetic gain over SP of 22, 7.2 or 30.8% for LS, BF and ADG, respectively, and over SI of 9.6, 3.8 or 21.4%. When …

Go to article

Alternative Methods Of Selection For Litter Size In Mice: I. Characterization Of Base Population And Development Of Methods, A. C. Clutter, Merlyn K. Nielsen, R. K. Johnson Nov 1990

Alternative Methods Of Selection For Litter Size In Mice: I. Characterization Of Base Population And Development Of Methods, A. C. Clutter, Merlyn K. Nielsen, R. K. Johnson

Department of Animal Science: Faculty Publications

Studies on a base population of mice were used to establish an index of components of litter size and a physiological model for measuring uterine capacity to be used subsequently in a selection experiment evaluating alternative methods for practicing selection to increase litter size. Heritability estimates of litter size, ovulation rate and ova success (fraction of ova resulting in fully formed pups) were .18, .33 and .15, respectively. No significant genetic or phenotypic correlation was found between overall ovulation rate and ova success. Phenotypic means and genetic variances were higher for characteristics measured on the right than on the left …

Go to article

Heterogeneous Within-Herd Variance. 1. Genetic Parameters For First And Second Lactation Milk Yields Of Grade Holstein Cows, T. H. Short, R. W. Blake, R. L. Quaas, L. Dale Van Vleck Jun 1990

Heterogeneous Within-Herd Variance. 1. Genetic Parameters For First And Second Lactation Milk Yields Of Grade Holstein Cows, T. H. Short, R. W. Blake, R. L. Quaas, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Genetic and environmental (co)variance components for 4% FCM yield were simultaneously estimated by REML for grade cows from herds stratified by within-herd SD for 305d mature equivalent milk and time period. Data were lactation records from 299,441 daughters of 2489 AI b d s that calved for the first time from 1970 to 1985 in California, New York, or Texas.
Sire and residual variance components for FCM increased with SD in all time periods and were slightly larger for second than for first lactations. Residual components were of uniform size across time periods within each SD class, but sire components …

Go to article

Heterogeneous Within-Herd Variance. 2. Genetic Relationships Between Milk Yield And Calving Interval In Grade Holstein Cows, T. H. Short, R. W. Blake, R. L. Quaas, L. Dale Van Vleck Jun 1990

Heterogeneous Within-Herd Variance. 2. Genetic Relationships Between Milk Yield And Calving Interval In Grade Holstein Cows, T. H. Short, R. W. Blake, R. L. Quaas, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Genetic and phenotypic (co)variances for mature equivalent yield of 4% FCM and calving interval were simultaneously estimated by REML for grade Holstein cows in first and second parity. Data were 305d mature equivalent lactation records and calving dates for 299,441 daughters of 2489 AI sires first calving from 1970 to 1985 in California, New York, or Texas. Data were divided into three time periods, and herds were partitioned into three within-herd-year phenotypic SD classifications for milk yield. Average FCM yield and calving interval increased with SD in all time periods for both parities. Genetic variance of calving interval showed no …

Go to article

Alternative Animal Models With Maternal Effects And Foster Dams, L. Dale Van Vleck Apr 1990

Alternative Animal Models With Maternal Effects And Foster Dams, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Effects of foster dams can be included in genetic evaluations using animal models with maternal effects in several ways. The alternatives discussed involve minor changes in computing strategies from strategies used with reduced animal models that predict breeding values for direct and maternal effects. The easiest alternative is to assign foster dams to groups by breed and time period and add equations for fixed effects of breed-period. Random and, assumed, independent effects of foster dams can be nested in breed-period groups. If foster dams do not repeat. then those effects can be absorbed into equations for other fixed effects, additive …

Go to article

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 Mar 1990

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.

Go to article

Absorption Of Equations For Non-Parents For An Animal Model With Maternal Effects And Genetic Groups, L. Dale Van Vleck Feb 1990

Absorption Of Equations For Non-Parents For An Animal Model With Maternal Effects And Genetic Groups, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Rules for forming the mixed-model equations for the reduced animal model with all relationships and including maternal effects have been set out by Quaas and Pollak. They also have shown how to simplify the mixed-model equations when genetic group effects are included in the model with what has become known as the Q-P transformation. Westell has given rules for calculating the coefficients for the Q-P transformed equations that are associated with the inverse of the numerator relationship matrix and genetic group effects. Those rules can be extended to include maternal effects and genetic groups for maternal as well as direct …

Go to article

Genotype By Environment Interactions For Milk And Fat Production Across Regions Of The United States, M. J. Carabano, K. M. Wade, L. Dale Van Vleck Jan 1990

Genotype By Environment Interactions For Milk And Fat Production Across Regions Of The United States, M. J. Carabano, K. M. Wade, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

(Co)variance components for regional production of milk, fat, and fat percentage were estimated via multiple-trait REML using DHIA data from California, New York, and Wisconsin. Data consisted of registered and grade first lactation yields of Holstein cattle from 1970 through 1984. Records were limited to daughters from sires common to the pairs of states analyzed. Averaged numbers of records from California, New York, and Wisconsin were 419,185, 460,296, and 449,866. Genetic correlations between New York and Wisconsin for milk, fat, and fat percentage (.99, .98, and .99) were larger than those between California and New York (.95, .95, and .98) …

Go to article

Breeding Value Prediction With Maternal Genetic Groups, L. Dale Van Vleck Jan 1990

Breeding Value Prediction With Maternal Genetic Groups, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

For models with only additive direct genetic effects, the rules of Westell combined with the Q-P transformation can be used to calculate the coefficients of mixed-model equations corresponding to the inverse elements of the numerator relationship matrix and group effects that are used to account for selection on ancestors that do not have records. Groups generally can be assigned on the basis of most recent ancestors without records. When maternal effects are in the model, most recent female ancestors without records contribute maternal effects to their progeny. If the vectors for additive direct and maternal effects do not include the …

Go to article

Differences In Cathepsin B + L And Calcium-Dependent Protease Activities Among Breed Type And Their Relationship To Beef Tenderness, M. Johnson, Chris R. Calkins, R. D. Huffman, D. D. Johnson, D. D. Hargrove Jan 1990

Differences In Cathepsin B + L And Calcium-Dependent Protease Activities Among Breed Type And Their Relationship To Beef Tenderness, M. Johnson, Chris R. Calkins, R. D. Huffman, D. D. Johnson, D. D. Hargrove

Department of Animal Science: Faculty Publications

Activities of acidic proteases (cathepsin B + L) and neutral, calcium-dependent proteases (CDP) were quantified to determine whether differences in proteolytic activity could explain differences in meat tenderness among breed types. Steers (n = 32) of known percentage Angus (A) and Brahman (B) breeding were used to establish differences in meat tendemess (A; 3/4A-1/4B; 1/2A-1/2B; 1/4A-3/4B). Samples were removed from the longissimus muscle within 1 h postmortem and within 2 h were frozen for subsequent determination of cathepsin B + L, CDP-I, CDP-II and CDP-inhibitor activities. Warner- Bratzler shear (WBS) was assessed after 1, 5 and 10 d of postmortem …

Go to article

Myofibrillar Protein Turnover In Feed-Restricted And Realimented Beef Cattle, Steven J. Jones, D. Starkey, Chris R. Calkins, J.D. Crouse Jan 1990

Myofibrillar Protein Turnover In Feed-Restricted And Realimented Beef Cattle, Steven J. Jones, D. Starkey, Chris R. Calkins, J.D. Crouse

Department of Animal Science: Faculty Publications

The objective of this study was to determine the effect of feed restriction and repletion on myofibrillar protein turnover in cattle. Crossbred steer calves (n = 12) about 310 d of age were assigned randomly to a diet of corn and silage that was 1) provided ad libitum for 146 d (ALC) or 2) restricted so steers gained .2 kg/d for 80 d but received ad libitum access to feed thereafter for 66 d (RFC). At 27, 55, 97, 118 and 146 d a 24-h urine sample and a blood sample were obtained. Urine was analyzed for Nτ-methylhistidine …

Go to article

First Prev Next Last