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Department of Animal Science: Faculty Publications

Articles 1081 - 1110 of 1242

Full-Text Articles in Animal Sciences

Age-Season Adjustment Factors For Alpine, Lamancha, Nubian, Saanen, And Toggenburg Dairy Goats, M. U. Iloeje, T. R. Rounsaville, R. E. Mcdowell, G. R. Wiggans, L. Dale Van Vleck Jan 1980

Age-Season Adjustment Factors For Alpine, Lamancha, Nubian, Saanen, And Toggenburg Dairy Goats, M. U. Iloeje, T. R. Rounsaville, R. E. Mcdowell, G. R. Wiggans, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Multiplicative age-season adjustment factors for milk and fat yields of five breeds of dairy goats were estimated by fitting a three-way, mixed classification model containing random effects for does with fixed effects for herd-year-season and age-season for 7544, 1994, 7456, 3307, and 4599 lactation records collected from 1965 to 1976 from Alpine, La- Mancha, Nubian, Saanen, and Toggenburg dairy goats in the United States. These factors reflect changes in milk and fat yields associated with age and season of freshening. As with dairy cattle, these factors indicated that milk records of goats are affected differently in different seasons for a …

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Sire Evaluation By Best Linear Unbiased Prediction For Categorically Scored Type Traits, L. Dale Van Vleck, P. J. Karner Jan 1980

Sire Evaluation By Best Linear Unbiased Prediction For Categorically Scored Type Traits, L. Dale Van Vleck, P. J. Karner

Department of Animal Science: Faculty Publications

Best linear unbiased prediction to predict category frequencies of future progeny of a sire for type traits scored in mutually exclusive categories is described. The method accounts for automatic covariances among categories and is comparable to prediction for multiple traits. The method does not require linearity of measurements and also allows nonlinear economic values to be assigned to each category after frequencies are predicted. Evaluations were for 12 descriptive type traits for 712 Brown Swiss bulls having daughters in more than one herd. Problems in obtaining solutions to the mixed-model equations for multiple traits are discussed.

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Stayability Evaluation As A Categorical Trait And By Considering Other Traits, L. Dale Van Vleck Jan 1980

Stayability Evaluation As A Categorical Trait And By Considering Other Traits, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Correspondence between usual categorical scores where frequencies sum to one and stayability of herd life measured as survival to several age periods is illustrated. The singularity of the variancecovariance matrix of categorically measured traits when each category is a separate trait also is true for stayability, since the measurement for the last period for stayability is always zero, has variance zero, and covariances zero with measurements in preceding periods. Best linear unbiased prediction for stayability of a bull's daughters is achieved by ignoring the last period. A procedure is described for predicting stayability of daughters having variable opportunity for stayability …

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Influence Of Lactobacillus Acidophilus Inoculum On Gnotobiotic And Conventional Pigs, D. S. Pollmann, D. M. Danielson, W. B. Wren, E. R. Peo, Jr., K. M. Shahani Jan 1980

Influence Of Lactobacillus Acidophilus Inoculum On Gnotobiotic And Conventional Pigs, D. S. Pollmann, D. M. Danielson, W. B. Wren, E. R. Peo, Jr., K. M. Shahani

Department of Animal Science: Faculty Publications

Two trials were conducted to determine the effect of L. acidopbilus (bacteria commonly found in probiotics) inoculum on gnotobiotic and conventional pigs. The localization and population levels of L. acidopbilus (LA) in the gastrointestinal (GI) tract of 24 gnotobiotic pigs (12 treated and 12 control) were determined by microbiological techniques.

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Lysine Requirement Of Pigs Weighing 5 To 15 Kg Fed Practical With And Without Added Fat, A. J. Lewis, E. R. Peo, Jr., B. D. Moser, T. D. Crenshaw Jan 1980

Lysine Requirement Of Pigs Weighing 5 To 15 Kg Fed Practical With And Without Added Fat, A. J. Lewis, E. R. Peo, Jr., B. D. Moser, T. D. Crenshaw

Department of Animal Science: Faculty Publications

Weanling crossbred pigs (average weight 5 kg) were fed diets containing two levels of fat and six levels of lysine in a 2 • 6 factorial design to determine the lysine requirement of young pigs fed practical diets with and without added fat. The diets were based on corn and soybean meal and contained either 5% sucrose or 5% lard. Lysine levels ranged from .95% (basal) to 1.45% in .10% increments. The growth trial was 28 days long and pigs were bled at 14 and 28 days. Feed intake (ADFI), weight gain (ADG), feed efficiency (G:F) and changes in plasma …

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Heterosis And Breed Effects In Swine, R. K. Johnson Jan 1980

Heterosis And Breed Effects In Swine, R. K. Johnson

Department of Animal Science: Faculty Publications

An objective of the NC-103 regional swine breeding project is to evaluate inter-population and intra-population performance of domestic and exotic strains of swine. Several cooperating stations have conducted experiments relative to this objective. Projects were not exact replicates, but sufficient overlap allowed combining the information to yield more precise estimates of heterosis and breed effects than was possible from the analyses of data from any single experiment. This publication summarizes data available from NC-103 cooperating stations on breed and heterosis effects in swine. An extensive crossbreeding experiment has been conducted and results published by Canadian researchers Fahmy and Bernard, 1971 …

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Adjustment Of 21-Day Litter Weight For Number Of Pigs Nursed For Purebred And Crossbred Dams, E. R. Wilson, R. K. Johnson Jan 1980

Adjustment Of 21-Day Litter Weight For Number Of Pigs Nursed For Purebred And Crossbred Dams, E. R. Wilson, R. K. Johnson

Department of Animal Science: Faculty Publications

Litter data from two crossbreeding experiments were used to estimate coefficients for regressing 21-day litter weight on litter size at 21-days. Exp. 1 involved 1,003 purebred and Fg gilts of Hampshire, Duroc and Yorkshire breeding and 206 second parity sows of Duroc, Hampshire and Yorkshire breeding; Exp. 2 involved 388 F1 gilts and sows of Duroc, Yorkshire, Landrace and Spot breeding. The linear and quadratic regression coefficients from the gilt data in Exp. 1 were 5.64 ± .29 kg/pig and -.10 ± .02 kg/(pig)2, respectively. For Exp. 2, the regression coefficients were 5.98 ± .71 kg/pig …

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Fragmentation Index Of Raw Muscle As A Tenderness Predictor Of Steaks From Us Good And Us Standard Steer And Bullock Carcasses, Chris R. Calkins, G. W. Davis Jan 1980

Fragmentation Index Of Raw Muscle As A Tenderness Predictor Of Steaks From Us Good And Us Standard Steer And Bullock Carcasses, Chris R. Calkins, G. W. Davis

Department of Animal Science: Faculty Publications

Thirty steer (10 US Good, 20 US Standard) and 10 bullock carcasses (one US Good, nine US Standard) were selected from two commercial meat packing firms and aged for 10 to 14 days in a 2 C cooler. Each carcass was assigned scores for the various USDA quality and yield grade factors during a 48- to 120-hr post-mortem selection period. Steaks containing the longissimus muscle were obtained from the anterior end of the short loin and cooked to 70 C. They were then measured for tenderness with the Warner-Bratzler shear and evaluated by a trained eight-member sensory panel.

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Effect Of Dietary Lactose On Gain, Feed Conversion, Blood, Bone And Intestinal Parameters In Postweaning Rats And Swine, R. L. Moser, E. R. Peo, Jr., T. D. Crenshaw, P. J. Cunningham Jan 1980

Effect Of Dietary Lactose On Gain, Feed Conversion, Blood, Bone And Intestinal Parameters In Postweaning Rats And Swine, R. L. Moser, E. R. Peo, Jr., T. D. Crenshaw, P. J. Cunningham

Department of Animal Science: Faculty Publications

Two trials were conducted to determine the effect of lactose on performance, bone integrity and certain blood constituents in post-weaning rats and swine. The effect of lactose on calcium and phosphorus and percentage ash content of the small intestine was also determined. In both trials, average daily gains were not influenced by the feeding of diets containing 30% lactose. Feed conversion was depressed in both rats and pigs when 30% lactose was fed.

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Effect Of Lactobacillus Acidophilus On Starter Pigs Fed A Diet Supplemented With Lactose, D. S. Pollmann, D. M. Danielson, E. R. Peo, Jr. Jan 1980

Effect Of Lactobacillus Acidophilus On Starter Pigs Fed A Diet Supplemented With Lactose, D. S. Pollmann, D. M. Danielson, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

Seventy-two crossbred pigs (average initial weight 6 kg) were used to study the effect of L. acidopbilus (lactic acid-producing bacteria common in probiotics) in starter diets on gain, feed conversion, fecal lactobacillus and coliform counts, hematology and serum proteins. The nonmedicated experimental diets were corn-soybean meal (18% crude protein) diets with two levels of lactose (0 and 10%). It has been theorized that lactose is necessary for lactobacilli to colonize in the digestive tract. One-half of the pigs received a 10-ml inoculum daily for 2 weeks via stomach tubes.

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Effect Of Various Levels Of Dietary Calcium And Phosphorus On Performance, Blood, And Bone Parameters In Growing Boars, R. D. Nimmo, E. R. Peo, Jr., B. D. Moser, P. J. Cunningham, D. G. Olson, T. D. Crenshaw Jan 1980

Effect Of Various Levels Of Dietary Calcium And Phosphorus On Performance, Blood, And Bone Parameters In Growing Boars, R. D. Nimmo, E. R. Peo, Jr., B. D. Moser, P. J. Cunningham, D. G. Olson, T. D. Crenshaw

Department of Animal Science: Faculty Publications

Ninety-six 8-kg crossbred boars were initially allotted to three dietary levels of calcium (Ca) and phosphorus (P) - (A) .65% Ca; .50% P; (B) .975% Ca; .75% P and (C) 1.3% Ca; 1.0% P - to determine the effects of the different levels on average daily gain (ADG), average daily feed intake (ADFI), feed to gain (F:G) and certain blood and bone parameters.

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Effects Of Microbial Feed Additives On Performance Of Starter And Growing-Finishing Pigs, D. S. Pollmann, D. M. Danielson, E. R. Peo, Jr. Jan 1980

Effects Of Microbial Feed Additives On Performance Of Starter And Growing-Finishing Pigs, D. S. Pollmann, D. M. Danielson, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

Three trials were conducted to evaluate the effect of lactic acid-producing microbial feed additives (Probiotics) on performance of starting and growing-finishing pigs. Two commercially available probiotics, Probios (L. acidopbilus) and Feed-Mate 68 (Streptococcus faecium type Cernelle 68), were used. In the first of two starter trials, 192 crossbred pigs (initial weight 7 kg) were used in a 2 • 4 factorial arrangement of treatments, with Probios and antibiotics (ASP-250, lincomycin, tylosin) as the main effects.

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Long-Term Effects Of Dietary Additions Of Alfalfa And Tallow On Sow Reproductive Performance, D. S. Pollmann, D. M. Danielson, M. A. Crenshaw, E. R. Peo, Jr. Jan 1980

Long-Term Effects Of Dietary Additions Of Alfalfa And Tallow On Sow Reproductive Performance, D. S. Pollmann, D. M. Danielson, M. A. Crenshaw, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

Eighty-eight crossbred sows were used to evaluate the effects of including sun-cured alfalfa in gestation diets and tallow in lactation diets on reproductive performance for three successive reproductive cycles.

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Response Of Different Genetic Lines Of Boars To Varying Levels Of Dietary Calcium And Phosphorus, R. D. Nimmo, E. R. Peo, Jr., B. D. Moser, P. J. Cunningham, T. D. Crenshaw, D. G. Olson Jan 1980

Response Of Different Genetic Lines Of Boars To Varying Levels Of Dietary Calcium And Phosphorus, R. D. Nimmo, E. R. Peo, Jr., B. D. Moser, P. J. Cunningham, T. D. Crenshaw, D. G. Olson

Department of Animal Science: Faculty Publications

Two experiments were conducted to determine the effect of various levels of dietary calcium (Ca) and phosphorus (P) on performance, soundness and blood and bone parameters of different genetic lines of boars fed under variable environmental conditions. The first experiment compared different genetic lines of boars fed two levels of dietary Ca and P. Forty purebred (Large White) and Nebraska Gene Pool boars were allotted by breed and initial weight to two levels of dietary Ca and P (.65 Ca/.50% P and 1.3% Ca/1.0% P).

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Effects Of Twinning On Lactation And Days Open In Holsteins, C. A. Chapin, L. Dale Van Vleck Jan 1980

Effects Of Twinning On Lactation And Days Open In Holsteins, C. A. Chapin, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Effects of twinning on lactation and days open in Holsteins were studied from calving records compiled by member surveys of Eastern Artificial Insemination Cooperative. Records of cows with 305-day mature-equivalent records from the Northeast Dairy Records Processing Laboratory were grouped according to whether the twin calving was associated with dystocia. Records of each cow that had a twin calving were paired with records of a single-calving control herdmate. In the twin group of 175 cows associated with dystocia, twin pregnancy had no effect on production; milk and fat production in the lactation initiated by twinning was depressed (137 kg and …

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Relationships Among Type Traits And Milk Yield Of Brown Swiss Cattle, L. Dale Van Vleck, P. J. Karner, G. R. Wiggans Jan 1980

Relationships Among Type Traits And Milk Yield Of Brown Swiss Cattle, L. Dale Van Vleck, P. J. Karner, G. R. Wiggans

Department of Animal Science: Faculty Publications

Variances and covariances for herdyear, sire, and residual effects were estimated for 10 standard type traits and milk yield from type records on 12,838 Brown Swiss cows and milk records on 5,911 of these. A total of 712 sires and 824 herds was involved. The model was a random two-way, cross-classified model (herd-year and sire of cow) with no interaction. Covariances with descriptive type traits scored in categories as present or absent also were estimated as were variance-covariance matrices for descriptive type traits when each category was a separate trait. Genetic correlations of standard type traits with final classification score …

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Estimating A Genetic Covariance From Least Squares Solutions, G. R. Wiggans, R. L. Quaas, L. Dale Van Vleck Jan 1980

Estimating A Genetic Covariance From Least Squares Solutions, G. R. Wiggans, R. L. Quaas, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

An unbiased and invariant procedure is described for estimating the covariance between effects of two traits or of random variables such as sires in two environments when the residual effects for one trait are not correlated with those of the other trait. When the covariance is desired between two classes in the model, such as sire of fetus and sire of cow, the data can be divided randomly into two sets to allow use of this procedure to estimate the covariance since the residuals in the two data sets would be uncorrelated. The method is to obtain solutions by ordinary …

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Profitability Index For Sires, J. J. Bakker, R. W. Everett, L. Dale Van Vleck Jan 1980

Profitability Index For Sires, J. J. Bakker, R. W. Everett, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

A profitability index for evaluation of sires on predicted lifetime production of daughters and their progeny was developed from sire evaluations for milk yield, fat yield, and stayability. Indexes of milk and stayability for first lactations were used to calculate proofs for stayability in later lactations. Predicted milk yields were adjusted to the actual age when the records would be made. Breed averages, which are required for the procedure, were calculated from records of daughters of 1192 Holstein-Friesian sires in the Northeast Artificial Insemination Sire Comparison. Proofs for stayability through the first lactation and indexes for stayability in later lactations …

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Reproductive Characteristics Of Boars During And After Exposure To Increased Ambient Temperature , R. P. Wettemann, M. E. Wells, R. K. Johnson Nov 1979

Reproductive Characteristics Of Boars During And After Exposure To Increased Ambient Temperature , R. P. Wettemann, M. E. Wells, R. K. Johnson

Department of Animal Science: Faculty Publications

Reproductive performance of 12 11-month-old Yorkshire boars was determined during and after exposure to control or increased ambient temperatures. After 3 weeks adjustment at 23 C in temperature controlled chambers, six boars were heat stressed by exposure to 34.5 ± 1.0 C for 8 hr and 31.0 ± 1.0 C for 16 hr during each 24-hr period and six control boars were maintained at 23.0 ± 1.0 C for 11 weeks. All boars were subsequently exposed to 23 C for 6 weeks. Semen was collected twice weekly before, during and after heat stress and boars were naturally mated with gilts …

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Efficiency Of Gains And Carcass Characteristics Of Swine Of Two Degrees Of Fatness Slaughtered At Three Weights, J. D. Neely, R. K. Johnson, L. E. Walters May 1979

Efficiency Of Gains And Carcass Characteristics Of Swine Of Two Degrees Of Fatness Slaughtered At Three Weights, J. D. Neely, R. K. Johnson, L. E. Walters

Department of Animal Science: Faculty Publications

Two hundred barrows and gilts were slaughtered at 100, 113 and 127 kg live weight. The sample was comprised of 36 litters, of which six litters within each breed of sire (Duroc, Hampshire and Yorkshire) were classified as fat litters (2.36 cm) and six litters classified as lean litters (2.16 cm) on the basis of litter mean backfat probes taken at 68 kg live weight.

Growth traits were evaluated from 9 weeks of age until the designated slaughter weight. Carcasses from the first replication (18 litters) were evaluated for percentage separable lean, fat and bone and those from the second …

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Components Of Variance Associated With Service Sire For Milk Yield And Reproductive Traits, L. P. Johnson, L. Dale Van Vleck Jan 1979

Components Of Variance Associated With Service Sire For Milk Yield And Reproductive Traits, L. P. Johnson, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

The association of service sire or sire of fetus with three milk yield traits and two reproductive intervals were investigated. Two procedures for estimation of variance components, Henderson's Method 1 and Method 3, were applied to a model of herd-year-season, sire of cow, and service sire. Analyses were for sire of calf born to initiate second lactation and service sire of the cow in second lactation. About 11,000 second lactation records on Holstein cows were available after editing for breeding and calving dates. Service sires and sires of cows were required to be in artificial insemination. Estimates by Method 1 …

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Value Of High Fiber Diets For Grand Swine, D. S. Pollmann, D. M. Danielson, E. R. Peo, Jr. Jan 1979

Value Of High Fiber Diets For Grand Swine, D. S. Pollmann, D. M. Danielson, E. R. Peo, Jr.

Department of Animal Science: Faculty Publications

An experiment was conducted to determine the effect of roughages on the utilization of dietary nitrogen, energy and fiber by gravid swine. Water consumption, backfat depletion, pregnancy weight gain, and reproductive performance were used as response criteria.

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Effect Of Graded Levels Of Bambermycins On Turkey Growth Performance, R.J. Grant, P.E. Waibel, T.W. Sullivan, C.L. Quarles Jan 1979

Effect Of Graded Levels Of Bambermycins On Turkey Growth Performance, R.J. Grant, P.E. Waibel, T.W. Sullivan, C.L. Quarles

Department of Animal Science: Faculty Publications

Three experiments were conducted in Minnesota, Nebraska, and Colorado to determine the effect on turkey performance of feeding graded levels of bambermycins (Flavomycin ®1) from one day of age to market weight. The body weight and feed efficiency values are averages for 22-week-old males and 18-week-old females. Bambermycins produced significant (P<.001; P<.05) improvements in body weight or feed efficiency in all three experiments. Composite average body weights at 0, 1.1, 2.2, and 4.4 mg bambermycins/kg diet were 10.40, 10.54, 10.59, and 10.64 kg, respectively. Overall, average feed efficiencies from bambermycins at 0, 1.1, 2.2, and 4.4 mg/kg of diet were 2.76, 2.73, 2.72, and 2.71, respectively.

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Growth Rate Of Thoroughbreds: Effect Of Age Of Dam, Year And Month Of Birth, And Sex Of Foal, R. L. Hintz, H. F. Hintz, L. Dale Van Vleck Jan 1979

Growth Rate Of Thoroughbreds: Effect Of Age Of Dam, Year And Month Of Birth, And Sex Of Foal, R. L. Hintz, H. F. Hintz, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Weight, height, and cannon bone measurements were obtained on 1,992 Thoroughbred foals. Colts were heavier than fillies at birth and the differences increased with age. Dams under 7 years of age and older than 11 years had foals of lighter weight at birth than mares 7 to 11 years of age and the differences persisted at 510 days of age. Foals born in April, May, or June were heavier than foals born in January, February, or March. Year of birth also influenced body weight. The trends for height at withers and cannon circumference were similar to those of body weight.

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Accuracy Of First Lactation Versus All Lactation Sire Evaluations By Best Linear Unbiased Prediction, G. R. Ufford, C. R. Henderson, J. F. Keown, L. Dale Van Vleck Jan 1979

Accuracy Of First Lactation Versus All Lactation Sire Evaluations By Best Linear Unbiased Prediction, G. R. Ufford, C. R. Henderson, J. F. Keown, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Variances of errors of prediction for sire evaluations which included only first records and for those with records of all lactations were compared for bulls of Ayrshire, Guernsey, Jersey, and Brown Swiss breeds used by artificial insemination with daughters having Dairy Herd Improvement records processed at the New York Dairy Records Processing Laboratory. The model for best linear unbiased prediction included fixed effects of sire group and herd-year-season of freshening and random effects of sires within group, sire-by-herd interaction (to account for environmental correlation among paternal sisters), cow within sire and herd, and residual. Variances of solutions for group effects …

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Computing Algorithms For Sire Evaluation With All Lactation Records And Natural Service Sires, G. R. Ufford, C. R. Henderson, L. Dale Van Vleck Jan 1979

Computing Algorithms For Sire Evaluation With All Lactation Records And Natural Service Sires, G. R. Ufford, C. R. Henderson, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Models for sire evaluation by best linear unbiased prediction procedures which consider all lactation records, an environmental correlation among paternal half-sisters in the same herd, herd-yearseason effects, genetic groups, and sires within groups are described. The computing algorithms are outlined briefly. Attention is drawn to a mimeographed publication of 46 pages (12) which describes in detail the computing algorithms for a model including an interaction between sire and herd (the environmental correlation) and a model which does not include the environmental correlation.

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Genetic And Herd-Year Variation In Type Traits Of Brown Swiss Cows, A. M. Moreno, G. R. Wiggans, L. Dale Van Vleck Jan 1979

Genetic And Herd-Year Variation In Type Traits Of Brown Swiss Cows, A. M. Moreno, G. R. Wiggans, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Type classification records of 15,697 Brown Swiss cows by 1955 sires in 852 herds were analyzed with a cross-classified (herd-year and sire of cow) model. Fractions of variance due to herd-year effects ranged from 8% for mammary system to 17% for body capacity. Within herd-year heritabilities ranged from 24% for feet and legs to 43% for final score. Descriptive traits were analyzed by the same model except that each category was treated as a binomial variable. Proportions of variance due to herd-year effects for the descriptive traits were generally below 10%. Heritabilities were generally below 15%.

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An Approximate Procedure For Determining Prediction Error Variances Of Sire Evaluations, G. R. Ufford, C. R. Henderson, L. Dale Van Vleck Jan 1979

An Approximate Procedure For Determining Prediction Error Variances Of Sire Evaluations, G. R. Ufford, C. R. Henderson, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Prediction errors of sire evaluations can be obtained directly from the inverse of the appropriate coefficient matrix. Considerably more effort is required to obtain the inverse in practical situations than can be justified for publication of a confidence figure. An approximate prediction error variance, k/(n + 20), is used currently in the Northeast Artificial Insemination Sire Comparison where n is the number of daughters and k is an appropriate breed constant corresponding to the residual variance. This procedure, however, does not account for distribution of sires across herds nor several lactations per daughter. Thus, the diagonal elements of the sire …

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Extending Partial Lactation Milk And Fat Records With A Function Of Last-Sample Production, G. R. Wiggans, L. Dale Van Vleck Jan 1979

Extending Partial Lactation Milk And Fat Records With A Function Of Last-Sample Production, G. R. Wiggans, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Holstein production records (364,328) from the Northeast were used to develop a procedure to extend in-progress and terminated records. A function was developed involving last-sample production which accounts for systematic influences in estimating remaining yield, which is yield from day of last sample to day 305. Last-sample production was used because remaining yield is estimated more accurately from last-sample production than from cumulative yield. The function is: estimated 305-day yield = yield in first n days + [(b1 + b2n) last production + (b3 + b4√n)/last production)] • (305-n). The coefficients (b's) were estimated …

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Fluctuations In Sire Evaluations, D. C. Bolgiano, L. Dale Van Vleck, R. W. Everett Jan 1979

Fluctuations In Sire Evaluations, D. C. Bolgiano, L. Dale Van Vleck, R. W. Everett

Department of Animal Science: Faculty Publications

Large fluctuations in an artificial insemination sire's evaluations concern both dairymen and artificial insemination studs. Characteristics of three bulls with high initial values which dropped on later evaluations were compared with those of 17 "normal" bulls. Characteristics included genetic yield, management, genetic trend, environmental trend, and size of herds where daughters freshened, genetic merit of mates, and average age at freshening of daughters in first lactation. Evidence suggests that fluctuations are from preferential treatment of daughters of some sires as well as randomness inherent in methods of sampling and evaluating sires.

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