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Department of Animal Science: Faculty Publications

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Full-Text Articles in Animal Sciences

Escape Protein Supplementation Of Yearling Steers Grazing Smooth Brome Pastures, S. J. Anderson, Terry J. Klopfenstein, V. Wilkerson Jan 1988

Escape Protein Supplementation Of Yearling Steers Grazing Smooth Brome Pastures, S. J. Anderson, Terry J. Klopfenstein, V. Wilkerson

Department of Animal Science: Faculty Publications

Two grazing trials utilizing individually supplemented yearling steers were conducted to study the effect of supplemental escape protein on steer performance during the active growth periods, spring and fall, of smooth brome (Bromus inermis). Graded levels (0, .11, .23 and .34 kg x head-1 x d-1) of an equal-protein-basis mixture of bloodmeal and corn gluten meal were offered daily, replacing corn starch, which was used as the negative control. All steers received 582 g supplemental dry matter per day. Supplementation with escape protein improved daily performance in both spring (P<.01) and fall (P<.02). Analysis of pooled data from both trials indicated a linear (P<.01) and quadratic (P<.05) increase in steer performance with increasing level of escape protein in the diet. Analysis of grass samples collected throughout and composited over each trial demonstrated that grass protein was highly degraded in the rumen. Using a modified dacron bag technique, 12-h degradability was found to be 80 to 90% of the potentially digestible protein fraction. Rates of protein degradability were 14 and 11.7%/h. Assuming 5%/h rate of passage, escape protein was calculated to be 9.2 and 13.1% of total protein. As a result of the significant growth response observed above that of the energy-supplemented controls and the high ruminat protein degradabilities of the grass observed in the laboratory, it was concluded that growing ruminants grazing actively growing smooth brome pastures were deficient in metabolizable protein.

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Relationship Between Herd Management Practices In The Midwest On Milk And Fat Yield, Jeffrey F. Keown Jan 1988

Relationship Between Herd Management Practices In The Midwest On Milk And Fat Yield, Jeffrey F. Keown

Department of Animal Science: Faculty Publications

A dairy management survey was conducted in fall 1985 and spring 1986 in the nine-state area served by the Midstates Dairy Records Processing Center in Ames, IA. The questionnaire, consisting of 57 questions with 254 possible choices, was used to survey dairy producers on DHI testing in Arkansas, Illinois, Iowa, Kansas, Missouri, Nebraska, North Dakota, Oklahoma, and South Dakota. The questions covered housing pactices, milking equipment and practices, feeding regimens, calf rearing and feeding, feed additives, various management categories, and artificial insemination usage. The survey responses were merged with the 1985 year end rolling herd production averages from the processing …

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Relative Economic Values Assigned To Milk, Fat Test, And Type In Pricing Of Bull Semen, J. S. Wilder, L. Dale Van Vleck Jan 1988

Relative Economic Values Assigned To Milk, Fat Test, And Type In Pricing Of Bull Semen, J. S. Wilder, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Data on 324 Holstein bulls from the July 1983 USDA Sire Summary and Holstein Association type evaluations were analyzed using multiple regression to determine which traits or combination of traits in a sire evaluation are most important in determining the price of a straw of semen. Over all bull studs, type was a major economic influence in determining price of semen. When bulls with outlier prices ($100 or more) were excluded, relative economic values over all buII studs were 4.31:2.63:1 for milk, type, and fat test. For three bull studs with more than 35 bulls with evaluations for milk, type, …

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Genetic Groups In An Animal Model, R. A. Westell, R. L. Quaas, L. Dale Van Vleck Jan 1988

Genetic Groups In An Animal Model, R. A. Westell, R. L. Quaas, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Rules are presented for assigning coefficients to the genetic group portion(s) of the mixed model equations after transformation to solve directly for total genetic value (group plus animal solutions) simultaneously for sires and cows using an animal model. Inclusion of all known relationships seems to reduce the need for groups to account for genetic selection and genetic trend. Migration of animals into a population, however, results in a need for grouping to account for genetic merit of the migrants. Selection of parents on which records are not available also creates a need for grouping. Group solutions represent the average genetic …

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Effect Of Uni Lateral Hysterectomy And Ovari Ectomy On Puberty, Uterine Size And Embryo Development In Swine, Ying-Tsorn Huang, R. K. Johnson, G. R. Eckhardt Oct 1987

Effect Of Uni Lateral Hysterectomy And Ovari Ectomy On Puberty, Uterine Size And Embryo Development In Swine, Ying-Tsorn Huang, R. K. Johnson, G. R. Eckhardt

Department of Animal Science: Faculty Publications

Eighty crossbred gilts were assigned randomly to treatments: 1) removal of an ovary and ipsilateral uterine horn (UHO) at 130 d of age and removal of the remaining ovary and uterine horn 12 d post-puberty; 2) UHO at 130 d of age, mated and reproductive tracts recovered when slaughtered at 30 d of gestation; 3) UHO 12 d post-puberty, mated and slaughtered at 30 d of gestation and 4) unoperated controls that were mated and slaughtered at 30 d of gestation. Age of puberty was not affected by treatments. Gilts in treatment 1 had a mean ovulation rate at the …

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Growth Performance For Four Breeds Of Swine: Crossbred Females And Purebred And Crossbred Boars, D. G. Mclaren, D. S. Buchanan, R. K. Johnson Aug 1987

Growth Performance For Four Breeds Of Swine: Crossbred Females And Purebred And Crossbred Boars, D. G. Mclaren, D. S. Buchanan, R. K. Johnson

Department of Animal Science: Faculty Publications

Purebred and two-breed cross (F1) boars were mated to F1 females to produce all possible three- and four-breed cross pigs involving the Duroc, Yorkshire, Landrace and Spotted breeds. Individual post-weaning average daily gain (ADG), age at 100 kg (AGE) and probed backfat thickness at 100 kg (BE) data were collected on 3,456 pigs. A total of 213 pens with an average of 15.58 pigs per pen was evaluated for post-weaning feed-to-gain ratio (F/G) and average daily feed consumption (ADF). Genotype x environment interactions, specifically breed x year-season farrowed and breed X parity (for ADG), were found to …

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Individual Heterosis And Breed Effects For Postweaning Performance And Carcass Traits In Four Breeds Of Swine, D. G. Mclaren, D. S. Buchanan, R. K. Johnson Jun 1987

Individual Heterosis And Breed Effects For Postweaning Performance And Carcass Traits In Four Breeds Of Swine, D. G. Mclaren, D. S. Buchanan, R. K. Johnson

Department of Animal Science: Faculty Publications

Individual heterosis and direct and maternal breed effects for postweaning average daily gain (ADG), off-test age (AGE) and probed backfat thickness (BF) were estimated from data on 1,664 pigs produced in a complete diallel mating system involving the Duroc, Yorkshire, Landrace and Spotted breeds. The same genetic parameters were estimated for various carcass traits by analyses of data collected on 269 barrow carcasses. Significant breed x environment (i.e., year-season farrowed, parity and sex) interactions were found for ADG, AGE and BF. Specific heterosis estimates for ADG and AGE were all highly significant and reasonably consistent among crosses. Overall heterosis for …

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Genetic Parameters For First Lactation Milk Yields At Three Levels Of Herd Production, J. C. De Veer, L. Dale Van Vleck Mar 1987

Genetic Parameters For First Lactation Milk Yields At Three Levels Of Herd Production, J. C. De Veer, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

A multivariate linear model was used to estimate sire variance and covariance components and residual variance components for first lactation milk yield and logarithms of yield at three herd production levels using Restricted Maximum Likelihood with the Expectation- Maximization algorithm. Data for four separate analyses were 305-d, mature equivalent first lactation milk records from cows sired artificially in the northeastern United States that freshened in 1970, 1971, 1976, and 1984. Respective numbers of records for each year were 42,618, 40,207, 33,581, and 34,196. Corresponding numbers of sires were 298, 289, 305, and 313. Herd production level was defined by mean …

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Aspects Of Selection For Performance In Several Environments With Heterogeneous Variances, D. J. Garrick, L. Dale Van Vleck Feb 1987

Aspects Of Selection For Performance In Several Environments With Heterogeneous Variances, D. J. Garrick, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Dairy cattle evaluation schemes routinely assume homogeneous variance with respect to environment. Increasing evidence suggests the presence of systematic changes in variance components associated with mean level of performance. Best linear unbiased prediction procedures that account for heterogeneity are reviewed. The consequences of incorrectly assuming homogeneity for evaluation are demonstrated for a progeny test and an artificial breeding program that screens dams of sires from heterogeneous populations. Selection assuming homogeneity can be very efficient when heritability, and therefore accuracy of selection, is greatest in the more variable environment. Conversely, appreciable reduction in response results when heritability is greater in the …

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Contemporary Groups For Genetic Evaluations, L. Dale Van Vleck Jan 1987

Contemporary Groups For Genetic Evaluations, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Contemporary groups are used to remove biases from genetic evaluations due to differential effects such as management associated with the grouping. Numerous groups, however, can result in small numbers of records per subclass with associated loss of effective number of daughters for sire evaluation and increased prediction error variance. Thus, in practice, mean square error, bias squared plus prediction error variance, may be more meaningful than bias alone or prediction error variance. Considering contemporary groups as fixed removes bias due to association between effects corresponding to contemporary groups and sires. If contemporary groups are considered random, then effective number of …

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Lack Of Evidence Of Cytoplasmic Inheritance In Milk Production Traits Of Dairy Cattle, P. D. Reed, L. Dale Van Vleck Jan 1987

Lack Of Evidence Of Cytoplasmic Inheritance In Milk Production Traits Of Dairy Cattle, P. D. Reed, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Heritability estimates, by year of freshening of daughter, were obtained from daughter-dam and granddaughter-granddam regressions using 61,482 triply matched first lactations of artificially sired Holstein cows obtained from the Northeast Dairy Records Processing Laboratory. After adjusting for herd-yearseason effects, residual effects may include additive and other genetic effects of the animal, maternal effects, cytoplasmic effects, and other environmental effects. Analysis of residuals showed that cytoplasmic effects accounted for no variation in milk and fat yield and fat percent. Weighted yearly heritability estimates and standard errors from daughter on dam regressions were .35 + .01 for milk yield, .30 + .01 …

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Simultaneous Genetic Evaluation Of Sires And Cows For A Large Population Of Dairy Cattle, R. A. Westell, L. Dale Van Vleck Jan 1987

Simultaneous Genetic Evaluation Of Sires And Cows For A Large Population Of Dairy Cattle, R. A. Westell, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

A strategy for simultaneous sire and cow evaluation of genetic merit was implemented. First lactation records of 1,074,971 Holstein cows in 20,065 herds were included. After inclusion of ancestors, there were 1,741,356 equations: 1,505,938 cow, 229,394 herd year- season, 6000 sire, and 24 genetic group equations. All known genetic relationships among animals were considered. Genetic group coefficients were assigned based on animals that had one or more parents unidentified. Mixed model equations from an animal model were transformed to solve for total additive genetic merit. The coefficient matrix was sparse with .00039% nonzero elements. Equations were blocked by herds. A …

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Relationships Between Rate Of Growth, Catheptic Enzymes And Meat Palatability In Young Bulls, Chris R. Calkins, S. C. Seideman, J. D. Crouse Jan 1987

Relationships Between Rate Of Growth, Catheptic Enzymes And Meat Palatability In Young Bulls, Chris R. Calkins, S. C. Seideman, J. D. Crouse

Department of Animal Science: Faculty Publications

Relationships between rate of growth, endogenous muscle enzymes and meat palatability were investigated in 48 young (13 mo) Angus bulls. After backgrounding for 4 mo, bulls were placed on a high-energy diet for 30 d, at which time they were assigned randomly to one of three feeding treatments: 1) high energy (ad libitum-fed), 2) maintenance energy (restriction-fed to maintain body weight) or 3) sub-maintenance energy (restriction-fed to lose .68 kg/d). Cattle were slaughtered after 30 or 60 d on trial. Cathepsins B and H and β-glucuronidase in the longissimus muscle were quantitated at slaughter. Serum hydroxyproline, longissimus muscle collagen, taste-panel …

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Effect Of Protein And Energy Intake By Primiparous Sows During Lactation On Sow And Litter Performance And Sow Serum Thyroxine And Urea Concentrations, J. H. Brendemuhl, A. J. Lewis, E. R. Peo, Jr. Jan 1987

Effect Of Protein And Energy Intake By Primiparous Sows During Lactation On Sow And Litter Performance And Sow Serum Thyroxine And Urea Concentrations, J. H. Brendemuhl, A. J. Lewis, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

The effects of protein and energy intakes by primiparous sows during a 28-day lactation on thyroxine (T4) and urea concentrations in blood serum of sows, and sow and litter performance were examined in two experiments.

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Influence Of Picolinic Acid On The Uptake Of Zinc-Amino Acid Complexes By The Everted Rat Gut, D. A. Hill, E. R. Peo, Jr., A. J. Lewis Jan 1987

Influence Of Picolinic Acid On The Uptake Of Zinc-Amino Acid Complexes By The Everted Rat Gut, D. A. Hill, E. R. Peo, Jr., A. J. Lewis

Department of Animal Science: Faculty Publications

Three hundred fifty rats were used in three experiments to: 1) validate the everted gut procedure as an in vitro technique for estimating Zn absorption, 2) determine the effect of increasing ratios of picolinic acid (PA) to Zn on Zn absorption and 3) determine the effect of PA on absorption of Zn and amino acid complexes at pH 6, 7 and 8.

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Effect Of Level Of Protein And Supplemental Choline On Reproductive Performance Of Gilts Fed Sorghum Diets, C. V. Maxwell, R. K. Johnson, W. G. Luce Jan 1987

Effect Of Level Of Protein And Supplemental Choline On Reproductive Performance Of Gilts Fed Sorghum Diets, C. V. Maxwell, R. K. Johnson, W. G. Luce

Department of Animal Science: Faculty Publications

A total of 214 gilts was used (two trials) to determine the effect of protein level and choline supplementation during gestation on weight gain, conception rate and subsequent reproductive performance. The gilts were fed either a 12 or 16% crude protein sorghum-soybean meal diet containing either a high supplemental choline level or no supplemental choline in a 2 • 2 factorial arrangement of treatments Conception rate was not influenced by either protein or choline level. Choline supplementation increased pig weight at 42 d of age (P<.14) and litter weight at 21 (P<.12) and 42 d (P<.1). Gilts fed the 16% protein diet produced larger pigs at 42 d (P<.13) and heavier litters at birth, (P<.l) 21 d (P<.14) and 42 d (P<.05) than gilts fed the 12% protein diet. A larger choline effect on litter size and pig and litter weight was observed for gilts fed the 12% protein diet than for those fed the 16% gestation diet, although the protein-choline interaction was not significant for any traits measured. The incidence of spraddle leg condition was low and was not affected by level of dietary protein or supplemental choline.

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Effect Of Level Of Protein And Supplemental Choline On Reproductive Performance Of Gilts Fed Sorghum Diets, C. V. Maxwell, R. K. Johnson, W. G. Luce Jan 1987

Effect Of Level Of Protein And Supplemental Choline On Reproductive Performance Of Gilts Fed Sorghum Diets, C. V. Maxwell, R. K. Johnson, W. G. Luce

Department of Animal Science: Faculty Publications

A total of 214 gilts was used (two trials) to determine the effect of protein level and choline supplementation during gestation on weight gain, conception rate and subsequent reproductive performance. The gilts were fed either a 12 or 16% crude protein sorghum-soybean meal diet containing either a high supplemental choline level or no supplemental choline in a 2 x 2 factorial arrangement of treatments Conception rate was not influenced by either protein or choline level. Choline supplementation increased pig weight at 42 d of age (P<.14) and litter weight at 21 (P<.12) and 42 d (P<.1). Gilts fed the 16% protein diet produced larger pigs at 42 d (P<.13) and heavier litters at birth, (P<.l) 21 d (P<.14) and 42 d (P<.05) than gilts fed the 12% protein diet. A larger choline effect on litter size and pig and litter weight was observed for gilts fed the 12% protein diet than for those fed the 16% gestation diet, although the protein-choline interaction was not significant for any traits measured. The incidence of spraddle leg condition was low and was not affected by level of dietary protein or supplemental choline.

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Effect Of Weight At Castration On Steer Performance In The Feedlot, M. A. Worrell, D. C. Clanton, Chris R. Calkins Jan 1987

Effect Of Weight At Castration On Steer Performance In The Feedlot, M. A. Worrell, D. C. Clanton, Chris R. Calkins

Department of Animal Science: Faculty Publications

One hundred eighty-eight male calves were randomly assigned to one of five treatments at about 6 wk of age to determine the effect of castration at different weights on feedlot performance and carcass characteristics. Calves were castrated at 70, 230. 320 or 410 kg or left intact. All calves received a 36-mg zeranol implant 60 d post-weaning and were re-implanted every 56 d for the duration of the trial (196 d). Animals were slaughtered between 14 and 15 mo of age. Intact males gained faster (P<.05) and were more efficient (P<.05) in converting feed to gain than the castrated males. There were no differences (P>.10) in average daily gain (ADG) or feed efficiency (F/G) for males castrated at …

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Estimation Of Genetic (Co)Variances For Milk Yield In First Three Lactations Using An Animal Model And Restricted Maximum Likelihood, H. Swalve, L. Dale Van Vleck Jan 1987

Estimation Of Genetic (Co)Variances For Milk Yield In First Three Lactations Using An Animal Model And Restricted Maximum Likelihood, H. Swalve, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Genetic relationships among lactation records are of interest because most selection of bulls is on first lactations. Selection also complicates estimation of genetic parameters. Techniques unbiased by selection should be used. Estimation of genetic and environmental (co)variances was done using restricted maximum likelihood with an expectation-maximization algorithm for an animal model. The algorithm involved solving mixed model equations by direct inversion of coefficient matrix that became feasible by neglecting relationships across herds. From data consisting of first to third lactation milk records of New York Holsteins, two computationally manageable subsets were selected of 15 herds each totaling 3070 and 2900 …

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Selection When Traits Have Different Genetic And Phenotypic Variances In Different Environments, L. Dale Van Vleck Jan 1987

Selection When Traits Have Different Genetic And Phenotypic Variances In Different Environments, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Falconer's concept that performance in environment 2 is a different trait from performance in environment 1 allows calculation of expected response in environment 2 if selection is from environment 1. Response to selection in environment 1 and correlated response in environment 2 depend on heritability and phenotypic variance in environment 1, genetic covariance between performance of identical genotypes in the two environments, and selection intensity. If selection is from performance in environment 2, direct response in environment 2 and correlated response in environment 1 also can be calculated. If selection is from animals in both environments and if selected genotypes …

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Factors Influencing Best Annual Racing Time In Finnish Horses, M. Ojala, L. Dale Van Vleck, R. L. Quaas Aug 1986

Factors Influencing Best Annual Racing Time In Finnish Horses, M. Ojala, L. Dale Van Vleck, R. L. Quaas

Department of Animal Science: Faculty Publications

The fixed effects of year of race, season of race, sex, method of start, annual number of starts, length of race and racetrack were evaluated on best annual racing time in Finnish Horses. Data included 1,378 records for 554 horses by 206 sires. Five models were assumed within the age groups from 3 to 6 yr. The annual number of starts, method of start and season of race effects were interrelated. An increase in number of starts was associated with considerable improvement in a horse's best annual racing time. Records should not, however, be adjusted for effect of annual number …

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Lambing Performance Of Morlam And Dorset Ewes Under Accelerated Lambing Systems, L. C. Iniguez, R. L. Quaas, L. Dale Van Vleck Jul 1986

Lambing Performance Of Morlam And Dorset Ewes Under Accelerated Lambing Systems, L. C. Iniguez, R. L. Quaas, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Two accelerated lambing systems, Morlam using Morlam sheep (USDA, Beltsville 1966 to 1975) and Carnal using Dorset ewes (Cornell 1978 to 1981), were evaluated for first lambing ages, interlambing intervals and conception probabilities. Morlam ewes were continuously exposed to rams over the year, while Carnal Dorset ewes were exposed every other month. Morlam lambs were mated as early as 367 d of age and Carnal Dorset lambs as early as 340 d. Early lambing was associated with higher rates of perinatal mortality (P>.05) and smaller litter size (P<.O1). Lambing years among Morlam ewes and season of birth of Carnal Dorset ewes influenced (P<.01) their first lambing ages. Lambing intervals averaged 293 and 303 d among Morlam and Carnal Dorset ewes, respectively. Age at first lambing and season in which the previous lambing occurred with influential factors (P<.01) on lambing intervals of Morlam ewes; longer intervals resulted when ewe lambs were mated at early ages (<12 mo), and when the previous lambing occurred in winter. Estimates of conditional probabilities of conception by month given the occurrence of estrus, reflected seasonal changes in both systems. The overall probability of conception for the Morlain system (P=.16) was relatively higher than that for the Carnal Dorset system (P=.14); numbers of lambings per ewe per yr were 1.28 and 1.21, respectively. Estimates of heritability for age at first lambing, lambing interval and conception probability were. 31, .06 and .30, respectively.

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Comparison Of Heritability Estimates From Daughter On Dam Regression With Three Models To Account For Production Level Of Dam, J. C. Deveer, L. Dale Van Vleck Apr 1986

Comparison Of Heritability Estimates From Daughter On Dam Regression With Three Models To Account For Production Level Of Dam, J. C. Deveer, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Three models were used to estimate heritabilities for milk yields at different production levels and for different years as twice the regression of daughter residual effects on dam residual effects. The denominator is the residual mean square for dams. The numerator is the difference between the residual term for sum of dam's and daughter's records and sum of residual terms for records of dams and daughters. Model 1 included sire of daughter and herd-year-season of daughters only. Model 2 included sire of daughter, herd-year-season of dam, and herd-year-season of daughter. Model 3 included sire of daughter and herdyear- season of …

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Genetic Parameter Estimates For Reproductive Traits Of Male And Female Littermate Swine, R. O. Bates, D. S. Buchanan, R. K. Johnson, R. P. Wetteman, R. W. Fent, L. K. Hutchens Mar 1986

Genetic Parameter Estimates For Reproductive Traits Of Male And Female Littermate Swine, R. O. Bates, D. S. Buchanan, R. K. Johnson, R. P. Wetteman, R. W. Fent, L. K. Hutchens

Department of Animal Science: Faculty Publications

Reproductive traits of purebred and crossbred pigs produced in a four-breed diallel mating system using the Duroc, Landrace, Spotted and Yorkshire breeds were collected for five consecutive farrowing seasons (two farrowing seasons/year) beginning in fall 1976. Paternal half-sib heritabilities and genetic correlations for testicular traits (120 boars from 36 sires), serum testosterone (TE) and luteinizing hormone (LH) concentrations before and after treatment with gonadotropin releasing hormone (GnRH; 131 boars from 37 sires) and breeding performance traits (151 boars from 38 sires) were estimated. Heritability estimates were generally small to moderate except for sperm/gram testis (SGT), LH concentrations before (LH0) and …

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Approximating Prediction Error Variances For Multiple Trait Sire Evaluations, S. A. Greenhalgh, R. L. Quaas, L. Dale Van Vleck Feb 1986

Approximating Prediction Error Variances For Multiple Trait Sire Evaluations, S. A. Greenhalgh, R. L. Quaas, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

The coefficient matrix for multiple trait (milk, fat, and protein) mixed model equations may be too large to obtain prediction error variances from inverse elements. The commonly used reciprocals of diagonal elements may not be accurate approximations when sire relationships or multiple traits are included since much information is contained in off-diagonal elements. Approximations incorporating increased information from coefficient matrix were compared with actual prediction error variances for multiple trait evaluations for milk, fat, protein, and dollar value (relationships included) of 229 Ayrshire and 248 Brown Swiss bulls. Six approximations were selection index using number of daughter records, inverses of …

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Genetic Change In Milk Yield Estimated From Simultaneous Genetic Evaluation Of Bulls And Cows, L. Dale Van Vleck, R. A. Westell, J. C. Schneider Feb 1986

Genetic Change In Milk Yield Estimated From Simultaneous Genetic Evaluation Of Bulls And Cows, L. Dale Van Vleck, R. A. Westell, J. C. Schneider

Department of Animal Science: Faculty Publications

Genetic trend for milk yield in the artificially sired Holstein population in the northeastern United States was estimated from solutions for simultaneous genetic evaluations of bulls and cows for an animal model using mixed model equations and including all known relationships among the population by years of birth of 1960 to 1980 (1978 for bulls). First lactation milk records of 1,074,971 artificially sired cows sired by 6000 bulls in 20,065 herds were used. Averages of estimated genetic value by year of birth were similar from solutions after 10, 20, and 30 rounds of iteration of the mixed model equations. The …

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Effects Of Adding Fat To The Sow Lactation Diet On Lactation And Rebreeding Performance, G. C. Shurson, M. G. Hogberg, N. Defever, S. V. Radecki, E. R. Miller, Win Butler Jan 1986

Effects Of Adding Fat To The Sow Lactation Diet On Lactation And Rebreeding Performance, G. C. Shurson, M. G. Hogberg, N. Defever, S. V. Radecki, E. R. Miller, Win Butler

Department of Animal Science: Faculty Publications

One-hundred-three multiparous sows were randomly assigned to one of two lactation diets containing either no supplemental animal fat (C) or 10% added fat (F) during two seasons, summer (S) and winter (W), in a 2 X 2 factorial arrangement of treatments. Sows were placed on their respective dietary treatments 1 wk prior to farrowing and were fed these diets ad libitum throughout the 28-d lactation period. Weekly feed intake and total feed intake were not affected by diet or season, while weekly metabolizable energy (ME) intake tended to be higher during wk 1 and 3, and was higher (P<.04) during wk 2 for sows fed diet F. Sow weight loss from farrowing to 21 d of lactation and to weaning (28 d) were unaffected by diet or season. Average pig birth weight was .15 kg higher (P<.O1) for pigs born during S compared with those born in W. Sows receiving diet F had heavier litters at 21 d (P<.01) and heavier average pig 21-d weights (P<.O1). This was primarily due to the 13.1% increase (P<.04) in estimated milk yield and the higher fat concentration (P<.O01) of milk consumed by the pigs nursing sows fed diet F. Interval between weaning and re-breeding was shortened by 5.9 d (P<.01) for sows during W than during S, and tended to be lower for sows fed diet F (7.3 d) compared with that of sows fed diet C (9.7 d). Farrowing percentage was unaffected by diet but tended to be increased during W (78.9%) compared with S (65.1%). No differences between mason or diet were noted on number of pigs born or number of pigs born alive in the subsequent parity. No diet • season interactions were observed, except for crude protein concentration of sow's milk, which was higher in milk from sows fed diet C during season W (P<.04).

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Heritability Estimates For First Lactation Milk Yield Of Registered And Nonregistered Holstein Cows, J. C. Schneider, L. Dale Van Vleck Jan 1986

Heritability Estimates For First Lactation Milk Yield Of Registered And Nonregistered Holstein Cows, J. C. Schneider, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Heritabilities of milk yield and fat test were estimated from first lactation records of 196,672 Holstein daughter-dam pairs separately for registered and nonregistered cows for four milk yield groups and by years of freshening of the daughter. The model included herd-season and sire of the daughter. Heritability estimates were similar for registered and nonregistered cows averaging about .33 for milk yield and .62 for fat test. Estimates of heritability increased slightly over time for both milk yield and fat test. Heritability of fat test was similar for all groups. Heritability estimates for milk yield, however, averaged about .25 in low, …

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Genetic Evaluation Of Holsteins In Columbia, B. Y. Abubakar, R. E. Mcdowell, L. Dale Van Vleck Jan 1986

Genetic Evaluation Of Holsteins In Columbia, B. Y. Abubakar, R. E. Mcdowell, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Original data consisted of 31,777 records of progeny of 1442 sires for calvings between 1975 and 1983. Unadjusted means for milk yield (kg), days in milk, days dry, calving interval, days carried calf, and age at calving were 4281, 267, 88, 421, 145, and 36.6. Estimated total variance for first lactation milk yield by Henderson's method 3 was 1,385,436 kg 2 with sire and error variances accounting for 1.8 and 98.2%. Heritabilities for milk yield, lactation length, age at calving, and days carried calf were .07, .06, 2.59, and .01. High estimate for age was attributed to confounding of sires …

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The Effects Of Rate Of Change In Body Weight On Tissue Development And Meat Quality Of Youthful Bulls, J. D. Crouse, Chris R. Calkins, S. C. Seideman Jan 1986

The Effects Of Rate Of Change In Body Weight On Tissue Development And Meat Quality Of Youthful Bulls, J. D. Crouse, Chris R. Calkins, S. C. Seideman

Department of Animal Science: Faculty Publications

Forty-eight Angus bulls about 13 mo of age were used to study the effects of rate of change in live weight on muscle fiber, collagen and sensory characteristics of meat. Bulls were fed a finishing diet before treatment, and assigned to three treatments: 1) negative, 2) zero or 3) positive weight gain for 30 or 60 d prior to slaughter. Treatments were imposed by adjusting feed intake. Seventy-two hours after slaughter, carcasses were observed for quality and yield grade characteristics and longissimus muscle samples were obtained for fiber type, collagen and sensory characterization. Carcass lean at the 12th rib interface …

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