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Full-Text Articles in Life Sciences
The Impact Of Heat Load On Cattle, Angela M. Lees, Veerasamy Sejian, Andrea L. Wallage, Cameron C. Steel, Terry L. Mader, Jarrod C. Lees, John B. Gaughan
The Impact Of Heat Load On Cattle, Angela M. Lees, Veerasamy Sejian, Andrea L. Wallage, Cameron C. Steel, Terry L. Mader, Jarrod C. Lees, John B. Gaughan
Department of Animal Science: Faculty Publications
Heat stress and cold stress have a negative influence on cattle welfare and productivity. There have been some studies investigating the influence of cold stress on cattle, however the emphasis within this review is the influence of heat stress on cattle. The impact of hot weather on cattle is of increasing importance due to the changing global environment. Heat stress is a worldwide phenomenon that is associated with reduced animal productivity and welfare, particularly during the summer months. Animal responses to their thermal environment are extremely varied, however, it is clear that the thermal environment influences the health, productivity, and …
Triennial Reproduction Symposium: Looking Back And Moving Forward—How Reproductive Physiology Has Evolved, Deb L. Hamernik, Andrea S. Cupp, John S. Davis
Triennial Reproduction Symposium: Looking Back And Moving Forward—How Reproductive Physiology Has Evolved, Deb L. Hamernik, Andrea S. Cupp, John S. Davis
Department of Animal Science: Faculty Publications
In honor of the 50th anniversary of the Society for the Study of Reproduction (SSR), a Triennial Reproduction Symposium was cosponsored by SSR and the American Society of Animal Science (ASAS). The Society for the Study of Reproduction was formed in 1967 when a group of reproductive biologists that were members of ASAS met with physician scientists and decided to organize a new scientific society. The goal of SSR was to promote the study of reproduction by fostering interdisciplinary communication among scientists, holding conferences, and publishing meritorious studies. Today after its 50th anniversary, the mission for SSR is to harness …
Genome-Wide Prediction Of Age At Puberty And Reproductive Longevity In Sows, Julie Kathleen Tart, Rodger K. Johnson, Justin W. Bundy, N. N. Ferdinand, A. M. Mcknite, Jennifer R. Wood, Phillip S. Miller, M. F. Rothschild, Matthew L. Spangler, Dorian J. Garrick, Stephen D. Kachman, Daniel C. Ciobanu
Genome-Wide Prediction Of Age At Puberty And Reproductive Longevity In Sows, Julie Kathleen Tart, Rodger K. Johnson, Justin W. Bundy, N. N. Ferdinand, A. M. Mcknite, Jennifer R. Wood, Phillip S. Miller, M. F. Rothschild, Matthew L. Spangler, Dorian J. Garrick, Stephen D. Kachman, Daniel C. Ciobanu
Department of Animal Science: Faculty Publications
Traditional selection for sow reproductive longevity is ineffective due to low heritability and late expression of the trait. Incorporation of DNA markers into selection programs is potentially a more practical approach for improving sow lifetime productivity. Using a resource population of crossbred gilts, we explored pleiotropic sources of variation that influence age at puberty and reproductive longevity. Of the traits recorded before breeding, only age at puberty significantly affected the probability that females would produce a first parity litter. The genetic variance explained by 1-Mb windows of the sow genome, compared across traits, uncovered regions that influence both age at …
Genome-Wide Association Analyses Of Sow Reproduction And Lifetime Productivity, Daniel Ciobanu
Genome-Wide Association Analyses Of Sow Reproduction And Lifetime Productivity, Daniel Ciobanu
Department of Animal Science: Faculty Publications
Concurrent with increased prolificacy, high sow death losses and replacement rates are serious economic and welfare issues facing producers. Reproductive failure is the most frequent reason for culling sows. Lifetime productivity is characterized by moderate heritability and high phenotypic variance and, as a result, substantial genetic variation is expected to exist in most populations. Traditional selection for sow reproductive longevity results is ineffective due to low heritability and late expression of the trait. The primary goal of this research project was to identify DNA markers associated with reproductive and sow lifetime productivity that can be used in nucleus herds to …
Identification Of Markers Associated With Sow Lifetime Productivity For Whole Genomic Selection, Daniel Ciobanu
Identification Of Markers Associated With Sow Lifetime Productivity For Whole Genomic Selection, Daniel Ciobanu
Department of Animal Science: Faculty Publications
Sows are more productive today than ever before. However, concurrent with increased prolificacy, high sow death losses and replacement rates are serious economic and welfare issues facing producers. Reproductive failure is the most frequent reason for culling sows. Length of productive life is moderately heritable and has high variance; thus, substantial genetic variation is expected to exist in most populations. Genetic improvement in the swine industry occurs from selection in nucleus herds and is then transmitted through the breeding pyramid in the multiplication process. Thus, it is critical to identify selection methods that can be applied in nucleus herds that …
Utilization Of Dried Distillers Grains For Developing Beef Heifers, J. L. Martin, Andrea S. Cupp, Richard J. Rasby, Z. C. Hall, Richard N. Funston
Utilization Of Dried Distillers Grains For Developing Beef Heifers, J. L. Martin, Andrea S. Cupp, Richard J. Rasby, Z. C. Hall, Richard N. Funston
Department of Animal Science: Faculty Publications
A 2-yr study was conducted at 2 locations to determine if supplementing beef heifers with dried distillers grains (DDG) as an energy source affected growth or reproduction. Spring-born crossbred heifers (n = 316) were blocked by age or sire and age and assigned randomly to DDG or control (dried corn gluten feed, whole corn germ, urea) supplement. Heifers received prairie hay in amounts sufficient for ad libitum intake and 0.59% of BW DDG or 0.78% of BW control supplement (DM basis). Supplements were formulated to be isocaloric, but protein degradability differed. Supplemental undegradable intake protein intake from DDG averaged 267 …
Effects Of Pre- And Postpartum Nutrition On Reproduction In Spring Calving Cows And Calf Feedlot Performance, Leslie Aaron Stalker, Don C. Adams, Terry J. Klopfenstein, D. M. Feuz, Richard N. Funston
Effects Of Pre- And Postpartum Nutrition On Reproduction In Spring Calving Cows And Calf Feedlot Performance, Leslie Aaron Stalker, Don C. Adams, Terry J. Klopfenstein, D. M. Feuz, Richard N. Funston
Department of Animal Science: Faculty Publications
Crossbred, spring-calving cows (yr 1, n = 136; yr 2, n = 113; yr 3, n = 113) were used in a 3- yr experiment to evaluate the influence of supplemental protein prepartum and grazing subirrigated meadow postpartum on pregnancy rates and calf feedlot performance. A 2 × 2 factorial arrangement of treatments was used in a switchback design. From December 1 to February 28, cows grazed dormant upland range in 8 pastures (32 ± 2 ha each). The equivalent of 0.45 kg of supplement/cow per d (42% CP) was provided to half of the cows on a pasture basis …
Genetic Relationship Between Milk Score And Litter Weight For Targhee, Columbia, Rambouillet, And Polypay Sheep, R. M. Sawalha, G. D. Snowder, Jeffrey F. Keown, L. Dale Van Vleck
Genetic Relationship Between Milk Score And Litter Weight For Targhee, Columbia, Rambouillet, And Polypay Sheep, R. M. Sawalha, G. D. Snowder, Jeffrey F. Keown, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
This study was conducted to evaluate the relationship between milk score (MS) and litter weight at 70 d (LW) for four sheep breeds in the United States. Milk score is a subjective measure of milk production used to assess milk production of range ewes when milk yield cannot be quantitatively determined. Variance components for MS and LW were estimated for each of Targhee, Columbia, Rambouillet, and Polypay breeds. Data collected from 1990 through 2000 at the U.S. Sheep Exp. Stn. in Dubois, ID, were analyzed with an animal model using REML. There were 13,900 records of MS and LW for …
A Genome Scan For Quantitative Trait Loci And Imprinted Regions Affecting Reproduction In Pigs, J. W. Holl, J. P. Cassady, D. Pomp, R. K. Johnson
A Genome Scan For Quantitative Trait Loci And Imprinted Regions Affecting Reproduction In Pigs, J. W. Holl, J. P. Cassady, D. Pomp, R. K. Johnson
Department of Animal Science: Faculty Publications
Quantitative trait loci for reproductive traits in a three-generation resource population of a cross between low-indexing pigs from a control line and high-indexing pigs from a line selected 10 generations for increased index of ovulation rate and embryonic survival are reported. Phenotypic data were collected in F2 females for birth weight (BWT, n = 428), weaning weight (WWT, n = 405), age at puberty (AP, n = 295), ovulation rate (OR, n = 423), number of fully formed pigs (FF, n = 370), number of pigs born alive (NBA, n = 370), number of mummified pigs (MUM, n = 370), …
Responses To 19 Generations Of Litter Size Selection In The Nebraska Index Line. I. Reproductive Responses Estimated In Pure Line And Crossbred Litters, D. B. Petry, Rodger K. Johnson
Responses To 19 Generations Of Litter Size Selection In The Nebraska Index Line. I. Reproductive Responses Estimated In Pure Line And Crossbred Litters, D. B. Petry, Rodger K. Johnson
Department of Animal Science: Faculty Publications
Our objective was to estimate responses in reproductive traits in the Nebraska Index line (I) after 19 generations of selection for increased litter size. Responses were estimated in dams producing pure line, F1, and three-way cross litters. A total of 850 litters were produced over six year-seasons, including 224 pure line litters, 393 F1 litters produced from I and C females mated with DanbredNALandrace (L) or Duroc- Hampshire (T) boars, and 233 litters by F1 L x I and L x C females mated with T boars. Contrasts of means were used to estimate the genetic …
Performance Of Mouse Lines Divergently Selected For Heat Loss When Exposed To Different Environmental Temperatures. I. Reproductive Performance, Pup Survival, And Metabolic Hormones, P. M. Kgwatalala, J. L. Deroin, Merlyn K. Nielsen
Performance Of Mouse Lines Divergently Selected For Heat Loss When Exposed To Different Environmental Temperatures. I. Reproductive Performance, Pup Survival, And Metabolic Hormones, P. M. Kgwatalala, J. L. Deroin, Merlyn K. Nielsen
Department of Animal Science: Faculty Publications
Mouse populations differing in metabolic rate have been developed through selection for high (MH) and low (ML) heat loss, along with the unselected controls (MC). Objectives of the study were to compare the MH, ML, and MC lines for reproductive performance, pup survival, and metabolic hormones when reared at 12, 22, and 31°C, and to search for line × environment interactions. Conception and litter size were recorded on the parent generation mice introduced to the environments at 11 wk of age and bred after a 3-wk acclimatization period. Survival of pups (pre-weaning to 3 wk; post-weaning from 3 to 9 …
Fat Supplementation And Reproduction In Beef Females, Richard N. Funston
Fat Supplementation And Reproduction In Beef Females, Richard N. Funston
Department of Animal Science: Faculty Publications
Inadequate dietary energy intake and poor body condition can negatively affect reproductive function. Supplemental lipids have been used to increase energy density of the diet and may also have direct positive effects on reproduction in beef cattle. Several fatty acid sources have been studied as they relate to reproductive function. Common sources include sunflower, safflower, cottonseed, rice bran, soybeans, fishmeal, animal tallow, and calcium salts of fatty acids. Fats have been fed before and after calving, during the breeding season, and during heifer development. Response to fat has been investigated through measuring body weight and body condition score, age at …
Evaluation Of Gene Expression In Pigs Selected For Enhanced Reproduction Using Differential Display Pcr: Ii. Anterior Pituitary, G. R. Bertani, C. D. Gladney, R. K. Johnson, Daniel Pomp
Evaluation Of Gene Expression In Pigs Selected For Enhanced Reproduction Using Differential Display Pcr: Ii. Anterior Pituitary, G. R. Bertani, C. D. Gladney, R. K. Johnson, Daniel Pomp
Department of Animal Science: Faculty Publications
The objective of this study was to identify differentially expressed genes in the anterior pituitary (AP) of sows selected for enhanced reproductive phenotypes. Selection in the Index (I) line was based on an index of ovulation rate and embryo survival, whereas random selection was used in the Control (C) line. Average numbers of fully formed piglets at birth were 12.5 ± 1.5 and 9.9 ± 2.0 for Line I and C sows used in this study, respectively. In order to induce luteolysis and synchronize follicle development, sows were injected (i.m.) with 2 mL of prostaglandin F2α analog between d …
Identification Of Quantitative Trait Loci Affecting Reproduction In Pigs, J. P. Cassady, R. K. Johnson, Daniel Pomp, G. A. Rohrer, L. Dale Van Vleck, E. K. Spiegel, K. M. Gilson
Identification Of Quantitative Trait Loci Affecting Reproduction In Pigs, J. P. Cassady, R. K. Johnson, Daniel Pomp, G. A. Rohrer, L. Dale Van Vleck, E. K. Spiegel, K. M. Gilson
Department of Animal Science: Faculty Publications
The objective of this research was to identify chromosomal regions harboring QTL affecting reproduction in pigs. A three-generation resource population was developed by crossing low-indexing pigs from a randomly selected control line (C) with high-indexing pigs of a line selected for increased index of ovulation rate and embryonic survival (I). Differences between Lines I and C at Generation 10 were 6.7 ova and 3.3 fetuses at 50 d of gestation and 3.1 fully formed and 1.6 live pigs at birth. Phenotypic data were collected on F2 females, born in three replicates, for ovulation rate (n = 423), age at …
Candidate Gene Analysis For Loci Affecting Litter Size And Ovulation Rate In Swine, R. C. Linville, Daniel Pomp, R. K. Johnson, M. F. Rothschild
Candidate Gene Analysis For Loci Affecting Litter Size And Ovulation Rate In Swine, R. C. Linville, Daniel Pomp, R. K. Johnson, M. F. Rothschild
Department of Animal Science: Faculty Publications
A candidate gene approach was used to determine whether specific loci explain responses in ovulation rate (OR) and number of fully formed (FF), live (NBA), stillborn, and mummified pigs at birth observed in two lines selected for ovulation rate and litter size compared with a randomly selected control line. Line IOL was selected for an index of OR and embryonic survival for eight generations, followed by eight generations of two-stage selection for OR and litter size. Line C was selected at random for 16 generations. Line COL, derived from line C at Generation 8, underwent eight generations of two-stage selection. …
Genetic Parameters Among Weight, Prolificacy, And Wool Traits Of Columbia, Polypay, Rambouillet, And Targhee Sheep, C. M. Bromley, G. D. Snowder, L. Dale Van Vleck
Genetic Parameters Among Weight, Prolificacy, And Wool Traits Of Columbia, Polypay, Rambouillet, And Targhee Sheep, C. M. Bromley, G. D. Snowder, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Genetic parameters for Columbia, Polypay, Rambouillet, and Targhee sheep were estimated using REML with animal models for prolificacy, weight, and wool traits. All bivariate analyses included a covariance between additive genetic effects for the two traits plus appropriate additional covariances. Number of observations by breed ranged from 5,140 to 7,095 for prolificacy traits, from 7,750 to 9,530 for weight traits, and from 4,603 to 34,746 for wool traits. Heritability estimates ranged from .03 to .11 for prolificacy traits (litter size at birth and litter size at weaning), from .09 to .26 for weight traits (birth weight and average daily gain), …
Genetic Parameters For Sex-Specific Traits In Beef Cattle, R. K. Splan, Larry V. Cundiff, L. Dale Van Vleck
Genetic Parameters For Sex-Specific Traits In Beef Cattle, R. K. Splan, Larry V. Cundiff, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
Data from 3,593 beef heifers and 4,079 of their steer paternal half-sibs were used to estimate genetic parameters of and among female growth and reproductive traits and male carcass traits. Estimates of heritability for adjusted 205-d weight, adjusted 365-d weight, age at puberty, calving rate, and calving difficulty measured on females were .16, .38, .47, .19, and .18, respectively; estimates for calving rate and calving difficulty were expressed on a normal scale. Estimates of heritability for hot carcass weight; retail product percentage; fat percentage; bone percentage; rib eye area; kidney, pelvic, and heart fat percentage; adjusted fat thickness; marbling score; …
Development Of Gilts And Boars For Efficient Reproduction, Donald G. Levis, Vernon D. Leibbrandt, Dale W. Rozeboom
Development Of Gilts And Boars For Efficient Reproduction, Donald G. Levis, Vernon D. Leibbrandt, Dale W. Rozeboom
Department of Animal Science: Faculty Publications
Successful introduction of replacement gilts and boars into the breeding herd is an important aspect of breeding herd efficiency. To attain herd efficiency, females must ovulate adequate numbers of viable ova, express estrus, show willingness to mate, and conceive in a regular manner. Males must produce adequate numbers of fertile spermatozoa, possess ability and show willingness to mate, and produce high-conception rates. If these qualities are properly developed, pregnancy rate and litter size will be maximized.
Variances Of Additive And Dominance Genetic Effects For Ovulation And Twinning Rates In A Population Selected For Twinning, L. Dale Van Vleck, K. E. Gregory
Variances Of Additive And Dominance Genetic Effects For Ovulation And Twinning Rates In A Population Selected For Twinning, L. Dale Van Vleck, K. E. Gregory
Department of Animal Science: Faculty Publications
Estimates of variances due to additive and dominance genetic effects and permanent and temporary environmental effects were obtained for ovulation and twinning rates from a composite population selected for twinning rate. Measures of ovulation rate after 11 mo of age on 2,317 heifers with a total of 19,209 measures were used. Twinning measures were on 1,522 first-parity cows, 1,311 later-parity cows with a total of 3,571 measures, and 1,704 all-parity cows with 5,100 measures. Models included fixed effects of year-season-age at calving for twinning, and year-season of birth, age in months, and calendar month of measurement for ovulation rate. Four …
Genetic Trend And Environmental Effects In A Population Of Cattle Selected For Twinning, L. Dale Van Vleck, K. E. Gregory
Genetic Trend And Environmental Effects In A Population Of Cattle Selected For Twinning, L. Dale Van Vleck, K. E. Gregory
Department of Animal Science: Faculty Publications
A selection experiment was established in 1981 to increase twinning rate in cattle. Results reported are through 1993 calf crops. Estimates of genetic parameters for a two-trait twinning and ovulation rate model with genetic groups were as follows: heritabilities of .03 for twinning and .07 for ovulation rates with a genetic correlation of nearly 1.00 and fractional permanent environmental variances of .06 for twinning and .05 for ovulation rate. Corresponding estimates when group effects were ignored were as follows: heritabilities of .08 and .08 and fractional permanent environmental variances of .02 and .04 for twinning and ovulation rates, respectively. Twinning …
Ten Generations Of Selection For Predicted Weight Of Testes In Swine: Direct Response And Correlated Response In Body Weight, Backfat, Age At Puberty, And Ovulation Rate, Rodger K. Johnson, Gregg R. Eckardt, Thomas A. Rathje, Denise K. Drudik
Ten Generations Of Selection For Predicted Weight Of Testes In Swine: Direct Response And Correlated Response In Body Weight, Backfat, Age At Puberty, And Ovulation Rate, Rodger K. Johnson, Gregg R. Eckardt, Thomas A. Rathje, Denise K. Drudik
Department of Animal Science: Faculty Publications
Selection for predicted weight of testes at 150 d of age (PWT) was practiced for 10 generations to determine the effect on reproductive and growth traits in swine. Mass selection among boars (line TS) or random selection (line C) was practiced beginning with the F3 generation of a Large White x Landrace composite population. Population size in each line was 40 to 45 litters by 15 sires per generation. Responses were estimated by regressions on cumulative selection differentials for PWT and on generation number and by mixed-model derivative-free REML procedures. The realized heritability of PWT was .35 ± .02 and …
Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp
Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp
Department of Animal Science: Faculty Publications
A genetic correlation near unity between ovulation rate in heifers and later twinning frequency led to consideration of using measures of ovulation rate in heifers for each estrous cycle, beginning at puberty, to increase accuracy of selection for twinning rate. An initial evaluation with a multiple trait animal model for predicting breeding values included six genetic groups: 1) selected Scandinavian bulls, 2) transfers from other populations at the Research Center to a twinning project, 3) early-purchased Holsteins, 4) late-purchased Holsteins, 5) early purchases-other breeds. and 6) late purchases-other breeds. For ovulation and twin measures, heritabilities of .l00 and .070 and …
Index Selection For Components Of Litter Size In Swine: Response To Five Generations Of Selection, S. M. Neal, R. K. Johnson, R. J. Kittock
Index Selection For Components Of Litter Size In Swine: Response To Five Generations Of Selection, S. M. Neal, R. K. Johnson, R. J. Kittock
Department of Animal Science: Faculty Publications
Selection for an index of ovulation rate (OR) and embryo (fetal) survival rate (ES) to 50 d of gestation (I = 10.6 x OR + 72.6 x ES) was practiced for five generations in a line that was a composite population of the Large White and Landrace breeds of swine. A control line sampled from the same population was selected randomly and mated. Ovulation rate and number of fetuses (FETS) were measured by laparotomy and ES was calculated as FETS/OR. The select line averaged 43 litters by 18 sires and the control line averaged 42 litters by 15 sires per …
Correlated Responses Of Carcass And Reproductive Traits To Selection For Rate Of Lean Growth In Swine, E. R. Cleveland, R. K. Johnson, P. J. Cunningham
Correlated Responses Of Carcass And Reproductive Traits To Selection For Rate Of Lean Growth In Swine, E. R. Cleveland, R. K. Johnson, P. J. Cunningham
Department of Animal Science: Faculty Publications
Mass selection for an index of increased post-weaning average daily gain and decreased backfat thickness was practiced for five generations. Litter size and weight for 221 gilt litters, birth weight and nipple number for 2,242 piglets and weaning weight at 42 d of age for 2,111 pigs were recorded. Carcass measurements were taken on 331 pigs. Differences between means of the lines (select control) were regressed on cumulative selection differential of the index. These regression coefficients were negative (P > .10) for total number born, number born alive, number weaned per litter, nipple number and carcass backfat thickness. Coefficients were …
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
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 …
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
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).
Testicular Growth In Boars Of Different Genetic Lines And Its Relationship To Reproductive Performance , Allan Schinckel, R. K. Johnson, R. A. Pumfrey, Dwane R. Zimmerman
Testicular Growth In Boars Of Different Genetic Lines And Its Relationship To Reproductive Performance , Allan Schinckel, R. K. Johnson, R. A. Pumfrey, Dwane R. Zimmerman
Department of Animal Science: Faculty Publications
Testicular growth of 377 boars was compared by obtaining in situ measurements of testes width and length and excised tissue weights. Two experiments involved a line selected nine generations for ovulation rate (OR) and a control line (CL), and two experiments contained boars of the OR line and two other lines; WL, a Large White-Landrace cross, and a line founded by crossing lines OR and CL and selected six generations for increased average daily gain and decreased backfat (LG line). In situ testes measurements were similar for the OR and CL lines and were curvilinearly related to age. The LG …
The Relationships Between Plasma Progesterone And Lh And The Numbers Of Corpora Lutea And Embryos In Purebred And Crossbred Gilts, R. P. Wettemann, R. K. Johnson, I. T. Omtvedt
The Relationships Between Plasma Progesterone And Lh And The Numbers Of Corpora Lutea And Embryos In Purebred And Crossbred Gilts, R. P. Wettemann, R. K. Johnson, I. T. Omtvedt
Department of Animal Science: Faculty Publications
Relationships between plasma progesterone and luteinizing hormone (LH) and the numbers of corpora lutea and embryos were determined in 133 8-month-old purebred Duroc, Hampshire and Yorkshire gilts and two-breed crosses among the three breeds. The numbers of corpora lutea and normal embryos were determined at slaughteronday 30.8 ± .2 of pregnancy, and progesterone and LH were quantified in plasma obtained the previous day. Progesterone concentrations in plasma were influenced by sire (P<.10), breed of dam (P<.05) and breed of sire x breed of dam (P<.05). Hampshire gilts had higher concentrations of progesterone in plasma than did Durocs (P<.05) and Yorkshires (P<.01). None of the effects in the model was significant for LH. Plasma progesterone and LH had heritability estimates of .48 ± .41 and .29 ± .40, respectively. Most genetic and phenotypic correlations of plasma progesterone and LH with other traits were small. These data indicate that progesterone concentrations in plasma at 30 days of pregnancy are not a satisfactory predictor of the numbers of corpora lutea and embryos. The differences in plasma progesterone between breeds illustrate the need to consider the breed of gilts when selecting animals for the study of luteal function or physiological factors that may influence progesterone concentrations in plasma.
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
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 …
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
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 …