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Department of Animal Science: Faculty Publications

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Full-Text Articles in Animal Sciences

Projection Factors For Goat Lactation Records, G. R. Wiggans, L. Dale Van Vleck, F. N. Dickinson Jan 1979

Projection Factors For Goat Lactation Records, G. R. Wiggans, L. Dale Van Vleck, F. N. Dickinson

Department of Animal Science: Faculty Publications

Projection factors based on production on the last day of sampling were developed for dairy goat milk and fat records. The 305-day lactation was divided into 13 stages varying from 10 to 40 days. The shortest stages were in early lactation. Sets of factors were developed for four ages at freshening, two seasons, two levels of herd production, and two breed groups. These classifications were necessary to avoid bias and improve accuracy. Cumulative yield factors also were developed with the same grouping of records. These factors are used when production for the last sample day is not available.

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Expected Economic Responses To Selection For Direct And Fetal Genetic Effects, L. Dale Van Vleck Mar 1978

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 …

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Estimation Of Heritabilities For Weight, Height And Front Cannon Bone Circumference Of Thoroughbreds, R. L. Hintz, H. F. Hintz, L. Dale Van Vleck Jan 1978

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.

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Technical Notes: Economic Weights For Direct And Fetal Genetic Effects In Choosing Sires, L. Dale Van Vleck Jan 1978

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 …

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Effect Of Proportion Of Concentrates In Herd Ration On Lactation Curves, G. R. Wiggans, L. Dale Van Vleck Jan 1978

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 …

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Genetics Of Dairy Goats: A Review, M. U. Iloeje, L. Dale Van Vleck Jan 1978

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.

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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 Jan 1978

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.

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Studies On The Feasibility Of Predicting Feedlot Performance From Certain Laboratory Grain Analyses, M. L. Galyean, D. G. Wagner, R. K. Johnson Jan 1978

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 …

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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 Jan 1978

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.

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Factors Affecting Twinning And Effects Of Twinning In Holstein Dairy Cattle, R. A. Cady, L. Dale Van Vleck Jan 1978

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.

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Factors Influencing Racing Performance Of The Standard-Bred Pacer, R. L. Hintz, L. Dale Van Vleck Jan 1978

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. …

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Breeding For Increased Protein Content In Milk, L. Dale Van Vleck Jan 1978

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 …

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Direct And Indirect Sire Evaluations For Fat Test And Economic Merit, G. R. Ufford, L. Dale Van Vleck Jan 1978

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 …

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Economic Analysis Of Protein Testing For Selection, R. D. Anderson, R. W. Everett, L. Dale Van Vleck Jan 1978

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 …

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Estimation Of Genetic Trends From Cow And Sire Evaluations, R. L. Hintz, R. W. Everett, L. Dale Van Vleck Jan 1978

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 …

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Reproductive And Testicular Characteristics Of Purebred And Crossbred Boars, E. R. Wilson, R. K. Johnson, R. P. Wettemann Nov 1977

Reproductive And Testicular Characteristics Of Purebred And Crossbred Boars, E. R. Wilson, R. K. Johnson, R. P. Wettemann

Department of Animal Science: Faculty Publications

One-hundred-ninety-five Duroc (D), Hampshire (H), Duroc x Hampshire (D x H) and Hampshire x Duroc (H x D) boars were evaluated for reproductive performance. One-hundred- sixteen boars were castrated at approximately 225 days of age to evaluate testicular and epididymidal weights and sperm numbers. Testes from crossbred boars were 95.33 ± 22.81 g heavier (P<.01) and contained 14.41 ± 3.92 billion more sperm (P<.01) than those from purebred boars. Testes from Hampshire boars were 50.40 ± 31.75 g heavier with 6.27 ± 5.45 billion more sperm than those from Durocs. There were no significant differences between breeds for caput-corpus epididymidal measurements. Durocs had 24.55 ± 12.16 billion more sperm (P<.05) in the cauda epididymis than Hampshire boars. Testes weight and testes sperm numbers were significantly correlated with caput-corpus epididymidal and cauda epididymidal sperm numbers. Correlations of testicular and epididymidal characteristics with growth rate and backfat to 100 kg were small and nonsignificant. Twenty 7.5-month to 9-month-old D1 D x H and H x D boars and 19 H boars were each mated to two Yorkshire gilts to evaluate reproductive efficiency. Conception rates were: D, 63.2%; D x H, 67.5%; H x D, 60.0%; and H, 48.6%. Number of embryos 30-days postbreeding was 10.66 ± .49 and 11.25 ± .43 (P>.10) for gilts mated to purebred and crossbred sires, respectively. Twenty-eight of 36 crossbred boars mated each time they were exposed to an estrus gilt but only 11 of 36 of the purebred boars mated each time. None of the crossbred boars failed to mate …

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Age-Season Adjustment Factors Considering Herd Feeding Practices, G. R. Wiggans, L. Dale Van Vleck Jun 1977

Age-Season Adjustment Factors Considering Herd Feeding Practices, G. R. Wiggans, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

The influence of percent of net energy in the herd's ration derived from concentrates on age-season effects was studied in New York Holstein Dairy Herd Improvement records. Ten feeding groups were defined by herd-feeding information. There was some increase in milk yield with an increasing proportion of concentrates in the ration. For six of these groups, the two highest, two middle, and two lowest in percent net energy from concentrates, age-season effects were calculated. The trends in age effects and seasonal effects were similar for all groups with the groups having a higher fraction of net energy from concentrates showing …

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Interpolation For Extension Factors, G. R. Wiggans, L. Dale Van Vleck May 1977

Interpolation For Extension Factors, G. R. Wiggans, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

A complete table of extension factors for all lengths of part records can be approximated closely from a much smaller table of reciprocals of the factors. The procedure is to use linear interpolation on the reciprocals from the small table. The required extension factor is the reciprocal of the result of interpolation. This procedure is more accurate than interpolation on the factors themselves since the reciprocals are more nearly linearly related to length of part record than are the extension factors themselves.

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Memorial: Marvel L. Baker May 1977

Memorial: Marvel L. Baker

Department of Animal Science: Faculty Publications

Marvel L. Baker, Professor Emeritus of Animal Science and Dean Emeritus of the College of Agriculture, University of Nebraska-Lincoln died April 20, 1977 after being in poor health for several months.

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An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. I. Phenotypic And Genetic Correlations, L. D. Young, R. K. Johnson, I. T. Omtvedt Apr 1977

An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. I. Phenotypic And Genetic Correlations, L. D. Young, R. K. Johnson, I. T. Omtvedt

Department of Animal Science: Faculty Publications

This study involved the records of 339 purebred Duroc, Hampshire and Yorkshire gilts and 192 two-breed cross gilts resulting from matings among the three breeds. The primary purpose of this paper was to investigate the relationship of prebreeding traits, including the growth of the gilt and her littermates, with subsequent measures of reproduction. Heritabilities were estimated for several traits and in general the estimates were somewhat higher than most estimates in the literature. Genetically, all measures of growth were favorably and moderately to highly correlated to ovulation rate, with the relationship being stronger for traits measured late in growth as …

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An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. Ii. Principal Component Analysis, L. D. Young, R. K. Johnson, I. T. Omtvedt Apr 1977

An Analysis Of The Dependency Structure Between A Gilt's Prebreeding And Reproductive Traits. Ii. Principal Component Analysis, L. D. Young, R. K. Johnson, I. T. Omtvedt

Department of Animal Science: Faculty Publications

Seventeen variables measured before breeding and three measures of reproduction were taken on 339 purebred Duroc, Hampshire and Yorkshire gilts and 192 two-breed cross gilts resulting from matings among these breeds. Eight principal components accounted for 90% of the dependency structure existing among the 17 traits measured before breeding. Two principal components accounted for 97% of the dependency structure existing among the three reproductive traits.

The first principal component (PCll) from the prebreeding traits was a general measure of growth ability and accounted for 28% of the variation in the 17 measurements. The second principal component (PC12) contrasted slow growing …

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Expected Phenotypic Response In Weaning Weight Of Beef Calves From Selection For Direct And Maternal Genetic Effects, L. Dale Van Vleck, David St. Louis, J. I. Miller Jan 1977

Expected Phenotypic Response In Weaning Weight Of Beef Calves From Selection For Direct And Maternal Genetic Effects, L. Dale Van Vleck, David St. Louis, J. I. Miller

Department of Animal Science: Faculty Publications

An equation is derived to predict expected phenotypic response to selection when the trait under selection is influenced by both direct and maternal genetic effects. The expected phenotypic response after the i+lth generation of selection is Pi+1 = (i+l){Delta}D + i{Delta}M + {Delta}MC where {Delta}D and {Delta}M are the averages of the genetic selection differentials of the parents for the direct and maternal effects and {Delta}MC is the maternal genetic selection differential for selected females. An example, corresponding to published reports of genetic variances and covariance for direct and maternal effects on weaning weight, illustrates the importance of the covariance …

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Reproductive Performance Of Swine Bred To Produce Purebred And Two-Breed Cross Litters, L. D. Young, R. K. Johnson, I. T. Omtvedt Dec 1976

Reproductive Performance Of Swine Bred To Produce Purebred And Two-Breed Cross Litters, L. D. Young, R. K. Johnson, I. T. Omtvedt

Department of Animal Science: Faculty Publications

These data included the records of 818 purebred gilts and sows of Duroc, Hampshire and Yorkshire breeding mated to produce all purebreds and all possible two-way crosses. A total of 212 gilts were slaughtered 30-day postbreeding (72 purebred matings and 140 crossbred matings) to evaluate ovulation rate, number of live embryos, average embryo length and embryo survival rate. A total of 450 litters (161 purebred and 289 crossbred) were farrowed to evaluate litter size, litter weight and average pig weight at O, 21 and 42 days postfarrowing. Litters were farrowed in the spring and fall of 1971 and 1973 and …

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Characterization Of Biological Types Of Cattle Iii. Carcass Composition, Quality And Palatability, R. M. Koch, M. E. Dikeman, D. M. Allen, M. May, J. D. Crouse, D. R. Campion Oct 1976

Characterization Of Biological Types Of Cattle Iii. Carcass Composition, Quality And Palatability, R. M. Koch, M. E. Dikeman, D. M. Allen, M. May, J. D. Crouse, D. R. Campion

Department of Animal Science: Faculty Publications

Composition and quality characteristics of 1,121 steer carcasses obtained after mating Hereford and Angus cows to Hereford, Angus, Jersey, South Devon, Limousin, Charolais and Simmental sires were compared at a (1) constant age, (2) constant weight, and (3) constant percentage of fat in the longissimus muscle. Taste panel evaluation was made on a subsample of 496 carcasses. Growth rate of retail product, fat trim and bone differed significantly among sire breed groups. Breed group differences in relative proportions of retail product, fat trim and bone were largest when compared at a constant carcass weight and smallest when compared at equal …

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Dairy Cattle Breeding: Contributions Of Research On Field Data, L. Dale Van Vleck Sep 1976

Dairy Cattle Breeding: Contributions Of Research On Field Data, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Papers about dairy cattle breeding published in the Journal of Dairy Science from 1960 through 1975 were categorized according to whether the data came from institutional herds or from field collection and also according to whether the research was done with support of a regional project. Most project papers involved institutional data. The vast majority of non-project papers made use of field data. Nearly all papers classified as theoretical were also associated with field data or field recommendations. The major impact of breeding research projects with field data has been from improved genetic evaluation for production and from development of …

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Effects Of Levels Of Crude Protein On Performance Of Growing Boars, W. G. Luce, R. K. Johnson, L. E. Walters May 1976

Effects Of Levels Of Crude Protein On Performance Of Growing Boars, W. G. Luce, R. K. Johnson, L. E. Walters

Department of Animal Science: Faculty Publications

Two trials involving 216 growing boars were conducted to study the effects of different levels of crude protein on daily gains, feed efficiency, feed intake and estimated carcass characteristics. The boars were fed either a 16, 18 or 20% crude protein ration from 23.8 to 55.8 kg (period 1). Upon completion of period 1, the protein level was reduced 2% for each treatment (14, 16 and 18%, respectively) from 55.8 to 99.6 kg (period 2).

Average daily gain increased linearly (P<.01) and feed required per unit gain decreased quadratically (P<.05) as the percent protein in the diet increased from 16 to 20% in period 1 and 14 to 18% in period 2. Average daily feed intake was similar for boars on each treatment. Scanned backfat thickness decreased linearly (P<.01) and scanned longissimus muscle area increased linearly (P<.05) as protein in the diet increased.

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Postweaning Performance And Carcass Merit Of Purebred And Two-Breed Cross Pigs, L. D. Young, R. K. Johnson, I. T. Omtvedt, L. E. Walters May 1976

Postweaning Performance And Carcass Merit Of Purebred And Two-Breed Cross Pigs, L. D. Young, R. K. Johnson, I. T. Omtvedt, L. E. Walters

Department of Animal Science: Faculty Publications

The feedlot records of 2,111 purebred and crossbred pigs representing all purebred and all possible two-way crosses of Duroc, Hampshire and Yorkshire were analyzed to evaluate average daily gain on test, age at 100 kg, average backfat probe of gilts, average daily feed consumption and feed conversion. A random sample of 392 barrows was used to evaluate carcass traits. The data were analyzed to determine breed of sire and breed of dam effects, to evaluate differences between reciprocal crosses and to estimate heterosis.

Breed of sire and breed of dam effects were significant for many of the traits evaluated. Straightbred …

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Availability Of Trypotophan In Some Feedstuffs For Swine, Pedro H. Rivera L., E. R. Peo, Jr., T. Stahly, B. D. Moser, P. J. Cunningham Jan 1976

Availability Of Trypotophan In Some Feedstuffs For Swine, Pedro H. Rivera L., E. R. Peo, Jr., T. Stahly, B. D. Moser, P. J. Cunningham

Department of Animal Science: Faculty Publications

Two experiments were conducted to determine the availability of tryptophan (Try) from corn (NC), opaque-2 corn (OC), milo (M) and freeze dried alfalfa (FDA) when fed to swine. The first experiment consisted of a growth trial involving 96 baby pigs and eight treatments. The basal diet containing .06% Try and 24.5% protein was supplemented with .015%, .030% and .045% L-Try. These four diets were used to establish a standard curve for growth. The other treatments were formed by adding the feedstuffs as the source of Try to the basal diet. Availabilities were determined by comparing growth responses. Try availabilities from …

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Sire Comparisons For Holsteins In Mexico Versus The United States And Canada, R. E. Mcdowell, G. R. Wiggans, J. K. Camoens, L. Dale Van Vleck, D. G. St. Louis Jul 1975

Sire Comparisons For Holsteins In Mexico Versus The United States And Canada, R. E. Mcdowell, G. R. Wiggans, J. K. Camoens, L. Dale Van Vleck, D. G. St. Louis

Department of Animal Science: Faculty Publications

Henderson's mixed model procedure was used to determine sire comparisons for Holstein sires from the United States, Canada, or local bred in 48 Mexican herds. For sires with five or more daughters, 74% of the sires in artificial insemination from the United States had plus values compared to 34% from Canada, 44% from the local stud, and 40% for local bred sires. Genetic correlations with Mexican sire comparisons were Northeast Artificial Insemination Sire Comparison with >20 daughters in Mexico .86, with 10 to 20 daughters .71, United States Department of Agriculture (USDA) proof >10 daughters .81, and Canada Northeast Artificial …

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Factors Affecting Performance Of Holsteins In Subtropical Regions Of Mexico, R. E. Mcdowell, J. K. Camoens, L. Dale Van Vleck, E. Christensen, E. Cabello Frias Jul 1975

Factors Affecting Performance Of Holsteins In Subtropical Regions Of Mexico, R. E. Mcdowell, J. K. Camoens, L. Dale Van Vleck, E. Christensen, E. Cabello Frias

Department of Animal Science: Faculty Publications

Effects of herd, year, age, season, and their interactions on milk yield, lactation length, and reproductive efficiency for purebred and high grade Holsteins were determined by analysis of variance of 17,255 lactation records from 48 herds in Mexico. Herds differed in all traits. Herd average milk yield ranged from 2620 to 7670 kg. Years, ages, and seasons were important to milk yield, but these variables had little influence on lactation length, days open, days dry, and calving interval. Most two-, three-, and four-way interactions for milk yield and days in milk were of importance. Main effects and interactions accounted for …

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