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Full-Text Articles in Life Sciences
Expected Economic Responses To Selection For Direct And Fetal Genetic Effects, L. Dale Van Vleck
Expected Economic Responses To Selection For Direct And Fetal Genetic Effects, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Expected responses in direct and fetal genetic values due to selection of heifers or bulls were computed for various combinations of heritabilities of direct and fetal effects, genetic correlations, economic weights, and kinds of relatives' records. If the economic weights are 1:3 for direct and fetal effects, then records of mates of the sire should be used for selection of both heifers and bulls for the heritabilities .16 to .32. If the economic weights are 1:1, use of records of the mates does not appear important for selection of bulls or heifers. Reliable estimates of genetic covariance and variances of …
Factors Affecting Twinning And Effects Of Twinning In Holstein Dairy Cattle, R. A. Cady, L. Dale Van Vleck
Factors Affecting Twinning And Effects Of Twinning In Holstein Dairy Cattle, R. A. Cady, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Data were obtained from 23,978 calving records collected by the Eastern Artificial Insemination Cooperative's Calving Survey. The survey information included breed, parity and size of dam, date of breeding and birth, identification of sire and maternal grandsire, sex, size, and vigor of calf, and difficulty of birth. Due to small numbers of records for non-Holstein breeds, only Holstein records were used in the analyses. As parity increased, the incidence of twinning increased (P<.05). Month of birth (conception) and the size of dam measured within parity did not affect the twinning rate. The heritability of twinning, estimated using the genetic covariance between paternal half-sibs was .05 over all parities and within parity was .06, .03, and .03 for the first, second and third parities, respectively. Length of gestation for twins was 5 days less (P<.05) than for singles. In addition, twins were smaller and weaker, and their birth was accompanied by more dystocia than monoparous calves (P<.05). Neonatal mortality was four times higher (P<.05) for twins as compared to single births. In view of these facts, it does not appear that selection programs designed to increase twinning rates would be desirable for Holstein dairy cattle.
Factors Influencing Racing Performance Of The Standard-Bred Pacer, R. L. Hintz, L. Dale Van Vleck
Factors Influencing Racing Performance Of The Standard-Bred Pacer, R. L. Hintz, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Generalized least squares solutions were used to estimate effects of post position, track condition, purse within class of race, and breaking stride on time at finish of the Standardbred pacer. A total of 30,181 race records made during the 1972 racing season were analyzed. All effects were found to have a significant influence on time at finish. Differences between effects were generally uniform across age groups. Since post position, track condition, purse within class of race, and breaking stride were found to have a substantial influence on racing performance, these factors should be considered when estimating a horse's racing ability. …
Breeding For Increased Protein Content In Milk, L. Dale Van Vleck
Breeding For Increased Protein Content In Milk, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
The principles of selection are reviewed as a basis for discussing selection for protein content of milk. The correlations among components of milk will cause correlated responses in all even when selection is for only one component. Selection for fractional composition of fat or protein would lead to increases in content of fat and protein, but the expected increases in total yields of fat and protein would be much less than if selection were for yield of milk, fat, or protein. Selection should be for milk, fat, and protein yield with relative economic emphasis determined by the net economic value …
Economic Analysis Of Protein Testing For Selection, R. D. Anderson, R. W. Everett, L. Dale Van Vleck
Economic Analysis Of Protein Testing For Selection, R. D. Anderson, R. W. Everett, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
The expected change in dollar return from incorporating milk, fat, and protein records in a selection index (Index 1) was compared to that from an index utilizing just milk and fat records (Index 2) under pricing systems paying for milk, fat, and protein.
Dollar return 1 was superior to dollar return 2 when there was either no payment for protein or high payment for protein. For sire selection the expected changes in dollar return for the two indices were equal at a price for protein of $.88 per kg whereas for cow selection the returns were equal at a protein …
Estimation Of Genetic Trends From Cow And Sire Evaluations, R. L. Hintz, R. W. Everett, L. Dale Van Vleck
Estimation Of Genetic Trends From Cow And Sire Evaluations, R. L. Hintz, R. W. Everett, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Milk production records of Ayrshire, Guernsey, Holstein, Jersey, and Brown Swiss in the Northeast were used to estimate trends in transmitting ability of sires and genetic merit of cows. Genetic trends in the transmitting ability of Artificial Insemination sires for the Ayrshire, Guernsey, Holstein, Jersey, and Brown Swiss breeds averaged 23.7, 14.6, 17.9, 18.3, and 34.7 kg per year.
Genetic trends in the AI cow populations averaged 36.1, 25.4, 26.1, 25.0 and 38.1 kg. The genetic trends of cow populations were less than twice the contribution of sires to genetic trends, indicating that estimating genetic trends in cow populations by …
Technical Notes: Economic Weights For Direct And Fetal Genetic Effects In Choosing Sires, L. Dale Van Vleck
Technical Notes: Economic Weights For Direct And Fetal Genetic Effects In Choosing Sires, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
A procedure is developed to determine the relative economic values of effects of sire of cow and sire of fetus. The economic weights for selection will depend on the time and discount rate. For example, for 10 yr and a 10% discount rate, the relative economic weights are 1.240 and 1.284 for the sire's direct genetic and fetal genetic effects when the fetal effect of the sire affects only the subsequent lactation of the mate of the sire. If the fetal effect is carried over to each future lactation of the mate, the relative economic weights are 1.240 for the …
Effect Of Energy Source Prior To Parturitian And During Lactation On Tissue Lipid, Liver Glycogen And Plasma Levels Of Some Metabolytes In The Newborn Pig, R. Dean Boyd, B. D. Moser, E. R. Peo, Jr., P. J. Cunningham
Effect Of Energy Source Prior To Parturitian And During Lactation On Tissue Lipid, Liver Glycogen And Plasma Levels Of Some Metabolytes In The Newborn Pig, R. Dean Boyd, B. D. Moser, E. R. Peo, Jr., P. J. Cunningham
Department of Animal Science: Faculty Publications
Two experiments were conducted to determine the effect of energy source (carbohydrate or fat), fed to sows prior to parturition and during lactation, on energy storage and some metabolite levels in the neonatal pig which may exert an influence on rate of survival.
Effect Of Proportion Of Concentrates In Herd Ration On Lactation Curves, G. R. Wiggans, L. Dale Van Vleck
Effect Of Proportion Of Concentrates In Herd Ration On Lactation Curves, G. R. Wiggans, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
The proportion of net energy in the herd's ration derived from concentrates as reported to Dairy Herd Improvement was the basis for defining five groups of milk production records from New York and New England. The relative daily milk production by season and stage of lactation was estimated for each group at two ages by a generalized least squares procedure. These solutions showed little variation due to the grouping by proportion of concentrates, but season of freshening and age were important. The mean yield did increase with an increasing proportion of concentrates, and, consequently, extension factors would differ by group …
Effect Of Energy Source Prior To Parturitian And During Lactation On Piglet Survival And Growth And On Milk Lipids, R. Dean Boyd, B. D. Moser, E. R. Peo, Jr., P. J. Cunningham
Effect Of Energy Source Prior To Parturitian And During Lactation On Piglet Survival And Growth And On Milk Lipids, R. Dean Boyd, B. D. Moser, E. R. Peo, Jr., P. J. Cunningham
Department of Animal Science: Faculty Publications
Two experiments were conducted to determine the effect of level and source of energy fed to sows prior to parturition and during lactation on birth weight, gain, and survival of piglets and fat content of the dam's milk.
Studies On The Feasibility Of Predicting Feedlot Performance From Certain Laboratory Grain Analyses, M. L. Galyean, D. G. Wagner, R. K. Johnson
Studies On The Feasibility Of Predicting Feedlot Performance From Certain Laboratory Grain Analyses, M. L. Galyean, D. G. Wagner, R. K. Johnson
Department of Animal Science: Faculty Publications
Data from 14 cattle feeding trials were utilized to study the relationship between several laboratory analyses and animal feed intake (INTAKE), gain (ADG) and feed efficiency (F/G). Laboratory analyses considered were 6, 12 and 24 hr in vitro dry matter disappearance (IV6, IV12, IV24, respectively); in vitro gas production in 1 hr and 6 hr (GP1 and GP6, respectively); and degree of gelatinization (GEL). A multiple regression equation with variables for treatment and trial classification, initial weight and the quadratic effect of initial weight was fit to the data. The effect of initial weight was significant for all three performance …
Estimation Of Heritabilities For Weight, Height And Front Cannon Bone Circumference Of Thoroughbreds, R. L. Hintz, H. F. Hintz, L. Dale Van Vleck
Estimation Of Heritabilities For Weight, Height And Front Cannon Bone Circumference Of Thoroughbreds, R. L. Hintz, H. F. Hintz, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
A total of 19,833 records on 1,992 Thoroughbred foals out of 813 dams and by 365 sires was used to estimate heritability of weight, height at withers, and front cannon bone circumference. Measurement ages ranged from 0 to 174 days. Records were adjusted for the fixed effects of age of dam, sex of foal, and month and year of birth of the foal. Body weight, height at withers and front cannon bone circumference tended to be rather lowly heritable during the first few months but were moderately to strongly heritable by 1 year of age.
Direct And Indirect Sire Evaluations For Fat Test And Economic Merit, G. R. Ufford, L. Dale Van Vleck
Direct And Indirect Sire Evaluations For Fat Test And Economic Merit, G. R. Ufford, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Evaluations for milk, fat yield, and fat test for Holstein sires in artificial insemination were calculated from first lactation records of Holstein daughters by best linear unbiased prediction procedures. Indirect evaluations for fat test also were calculated by adding best linear unbiased predictions for milk and fat yield to breed averages for milk and fat yield to calculate test and then subtracting breed average fat test. The indirect evaluation for test had a simple correlation of .99 with fat test from best linear unbiased prediction. Dollar value indexes were calculated from evaluations for milk yield and from evaluations for fat …
Genetics Of Dairy Goats: A Review, M. U. Iloeje, L. Dale Van Vleck
Genetics Of Dairy Goats: A Review, M. U. Iloeje, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
The literature on genetics of dairy goats was reviewed to point out not only world wide research but also the need for research in the United States to achieve the goal of uniform national genetic evaluations similar to those now available for dairy cattle. The number of breeds studied and the variety of research are remarkable. The numbers of animals and records involved in most studies, however, suggest large sampling variances of estimates.