Animal Sciences Commons^™

Utilizing NuTrack To Access The Activity Levels In Pigs With Varying Degrees Of Genetic Potential For Growth And Feed Intake, Dalton Obermier, Melanie Trenahile-Grannemann, Ty B. Schmidt, Tom Rathje, Benny Mote

Department of Animal Science: Faculty Publications

Feed cost accounts for over two-thirds of the variable cost of production. In order to reduce feed costs without sacrificing production numbers, feed efficiency must be improved. Calorie expenditure has been difficult to quantify in the past but is understood to impact residual feed intake (RFI) greatly. The objective of this work was to utilize an advanced computer vision system to evaluate activity levels across sex and sire groups with different expected breeding value combinations for growth and feed intake. A total of 199 pigs from four different sire groups (DNA Genetics Line 600) High Feed Intake/High Growth (HIHG), Low …

Evaluating Equations Estimating Change In Swine Feed Intake During Heat And Cold Stress, R. R. White, P. S. Miller, M. D. Hanigan

Department of Animal Science: Faculty Publications

The objectives of this study were to evaluate heat stress feed intake models for growing swine using a data set assembled from the literature and to develop a series of new equations modeling the influence of the thermal environment and interactions between the thermal environmental and other factors on feed intake. A literature survey was conducted to identify studies assessing intake responses to temperature. The resulting data set comprised 35 studies containing 120 comparisons to thermoneutral intake. Intake as a fraction of thermoneutral intake (FFI) was the primary response variable, where a value of 1 represented no change from thermoneutral …

Effect Of Lysozyme Or Antibiotics On Faecal Zoonotic Pathogens In Nursery Pigs, J E. Wells, E. D. Berry, N Kalchayanand, L A. Rampel, M Kim, W. T. Oliver

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Aims: The objective of this study was to determine the effect of lysozyme and antibiotics on zoonotic pathogen shedding in faeces from nursery pigs housed without and with an indirect disease challenge. Methods and Results: Two replicates of approximately 650 pigs each were weaned and randomly assigned to one of 24 pens in either a nursery room that had been fully disinfected or a nursery room left unclean. Pigs were randomly assigned to control diet (Control), control diet + antibiotics (Antibiotic; chlortetracycline and tiamulin), or control diet + lysozyme (Lysozyme; 100 mg kg ^-1 diet). Rectal swab samples were collected …

A Cooperative Study On The Standardized Total-Tract Digestible Phosphorus Requirement Of Twenty-Kilogram Pigs, O. Adeola, M. J. Azain, S. D. Carter, T. D. Crenshaw, M. J. Estienne, B. J. Kerr, M. D. Lindemann, C. V. Maxwell, P. S. Miller, M. C. Shannon, E. Van Heugten

Department of Animal Science: Faculty Publications

A cooperative study comprising growth performance, bone mineralization, and nutrient balance experiments was conducted at 11 stations to determine the standardized total-tract digestible (STTD) P requirement of 20-kg pigs using broken-line regression analysis. Monocalcium phosphate and limestone were added to a corn–soybean meal–based diet at the expense of cornstarch to establish 6 concentrations of STTD P from 1.54 to 5.15 g/kg in increments of 0.62 g/kg at a constant Ca:total P of 1.52:1.0. Diets were fed to 936 pigs (average initial BW of 19 kg) in 240 pens for 20 replicate pens of barrows and 20 replicate pens of gilts …

Characterizing Linkage Disequilibrium In Pig Populations, Feng-Xing Du, Archie C. Clutter, Michael M. Lohuis

Department of Animal Science: Faculty Publications

Knowledge of the extent and range of linkage disequilibrium (LD), defined as non-random association of alleles at two or more loci, in animal populations is extremely valuable in localizing genes affecting quantitative traits, identifying chromosomal regions under selection, studying population history, and characterizing/managing genetic resources and diversity. Two commonly used LD measures, r² and D’, and their permutation based adjustments, were evaluated using genotypes of more than 6,000 pigs from six commercial lines (two terminal sire lines and four maternal lines) at ~4,500 autosomal SNPs (single nucleotide polymorphisms). The results indicated that permutation only partially removed the dependency of …

Incidence Of Splayleg Pigs In Nebraska Litter Size Selection Lines, J. W. Holl, R. K. Johnson

Department of Animal Science: Faculty Publications

Genetic parameters for the splayleg (SL) condition were estimated from 37,673 records of pigs from six lines derived from a Large White–Landrace base population. Random selection for 22 generations was practiced in Lines C1 and C2. Line C2 was derived from C1 at Generation 8. Selection lines were as follows: 1) Line I, selected 11 generations for an index of ovulation rate and embryonic survival followed by 11 generations of selection for litter size; 2) Line IOL, derived from Line I at Generation 8 and which underwent eight generations of two-stage selection for ovulation rate and number of fully formed …

National Pork Producers Council Maternal Line Genetic Evaluation: A Comparison Of Growth And Carcass Traits In Terminal Progeny, J. P. Cassidy, O. W. Robison, R. K. Johnson, J. W. Mabry, L. L. Christian, M. D. Tokach, R. K. Miller, R. N. Goodwin

Department of Animal Science: Faculty Publications

The objective of this study was to compare growth and carcass traits of 1,252 progeny of six commercially available dam lines included in the National Pork Producers Council Maternal Line Evaluation Project. Lines compared included one maternal line supplied by each of American Diamond Swine Genetics (ADSG), Danbred NA (DB), two lines supplied by Monsanto Choice Genetics (DK and GPK347), Newsham Hybrids (NH), and Landrace × Large White females supplied by the National Swine Registry (NSR). All females were mated to DB, Duroc-Hampshire terminal sires. Traits analyzed were ADG from 56 to 115 kg live weight, days to 115 kg, …

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 Ne Index Line. Ii. Growth And Carcass Responses Estimated In Pure Line And Crossbred Litters, D. B. Petry, J. W. Holl, R. K. Johnson

Department of Animal Science: Faculty Publications

Our objective was to estimate responses in growth and carcass traits in the NE Index line (I) that was selected for 19 generations for increased litter size. Differences between Line I and the randomly selected control line (C) were estimated in pure line litters and in F₁ and three-way cross litters produced by mating I and C females with males of unrelated lines. Contrasts of means were used to estimate the genetic difference between I and C and interactions of line differences with mating type. In Exp 1, 694 gilts that were retained for breeding, including 538 I and …

Evaluation Of Procedures To Predict Fat-Free Lean In Swine Carcasses, Rodger K. Johnson, E. P. Johnson, R. Goodwin, J. W. Mabry, R. K. Miller, O. W. Robison, H. Sellers, M. D. Tokach

Department of Animal Science: Faculty Publications

The objectives were to develop equations for predicting fat-free lean in swine carcasses and to estimate the prediction bias that was due to genetic group, sex, and dietary lysine level. Barrows and gilts (n = 1,024) from four projects conducted by the National Pork Board were evaluated by six procedures, and their carcass fat-free lean was determined. Pigs of 16 genetic groups were fed within weight groups one of four dietary regimens that differed by 0.45% in lysine content and slaughtered at weights between 89 and 163 kg. Variables in equations included carcass weight and measures of backfat depth and …

The National Pork Producers Council Maternal Line National Genetic Evaluation Program: A Comparison Of Six Maternal Genetic Lines For Female Productivity Measures Over Four Parities, J. S. Moeller, R. K. Johnson, J. W. Mabry, T. J. Baas, O. W. Robison

Department of Animal Science: Faculty Publications

Litter (n = 8,424) and female performance records were collected in two breed-to-wean production units in order to evaluate genetic line differences for sow longevity and maternal performance over four parities. Lines evaluated were American Diamond Genetics, Danbred North America, Dekalb-Monsanto DK44, Dekalb-Monsanto GPK347, Newsham Hybrids, and National Swine Registry. Females within a line were derived from a minimum of 65 sires, 197 dams (three dams per sire), and a maximum of three daughters per dam, except in the GPK347, which were produced using semen from 12 Nebraska Index boars mated with Dekalb-Monsanto Line 34 females. All lines expressed 100% …

Correlated Response In Placental Efficiency In Swine Selected For An Index Of Components Of Litter Size, H. Mesa, T. J. Safranski, R. K. Johnson, W. R. Lamberson

Department of Animal Science: Faculty Publications

The objective of this study was to evaluate correlated response in placental efficiency to selection for components of litter size. Fourteen generations of selection had resulted in a difference between lines of three fully formed piglets at birth. Gilts from a line selected for an index of components of litter size (S, n =33) and a randomly selected control (C, n =27) were observed at farrowing. At delivery, the umbilical cord of each piglet was double tagged with identically numbered mouse ear tags to allow the piglet’s weight to be matched to the corresponding placental weight. Litter size, placental weight, …

Rapid Communication: Mapping Of The Beta Tropomyosin (Tpm2) Gene To Pig Chromosome 1, J. Sherwood, Daniel C. Gill, M. F. Rothschild

Department of Animal Science: Faculty Publications

Locus. Pig Tropomyosin beta (TPM2) gene.

Genus and Species. Sus Scrofa.

Source and Description of Primers. Primers were derived by using well-conserved regions of published human and mouse sequence (GenBank accession nos. AF209746 and NM_009416). The primers were used to amplify a 1.4-kp fragment of the porcine TPM2 gene covering exons 3 through 8. The porcine cDNA sequence (GenBank accession no. AF420022) showed 95% exonic identity (325 bp) at the nucleotide level to the human skeletal muscle beta tropomyosin (GenBank accession no. X06825). Additionally, pig specific primers were designed to amplify a 246-bp piece that spans exons 3 to …

Rapid Communication: Mapping Of The Ca2+ Atpase Of Fast Twitch 1 Skeletal Muscle Sarcoplasmic Reticulum (Atp2a1) Gene To Porcine Chromosome 3, Daniel C. Ciobanu, Y. Ciobanu, M. F. Rothschild

Department of Animal Science: Faculty Publications

Locus Name. Ca²⁺ ATPase of fast twitch 1 skeletal muscle sarcoplasmic reticulum.

Species. Sus scrofa.

Locus Symbol. ATP2A1.

Source of Primers. Two sets of PCR primers were designed based on human ATP2A1 sequences (Gen- Bank accession numbers U96773 and U96777) available in the GenBank database. Using pig genomic DNA as a template we used set A primers to amplify approximately 1,100 bp spanning exon 1 to exon 2 and set B primers to amplify 1,200 bp gene segment covering some of exon 8 through part of exon 9. These sequences were deposited in GenBank, accession number AY027797-AY027799.

Direct And Correlated Responses To Two-Stage Selection For Ovulation Rate And Number Of Fully Formed Pigs At Birth In Swine, A. Ruiz-Flores, R. K. Johnson

Department of Animal Science: Faculty Publications

Our objectives were to estimate responses and genetic parameters for ovulation rate, number of fully formed pigs at birth, and other production traits following two-stage selection for increased ovulation rate and number of fully formed pigs. Eight generations of selection were practiced in each of two lines. One selection line was derived from a line that previously selected eight generations for an index to increase ovulation rate and embryonic survival (the IOL pigs). The other selection line was derived from the unselected control line of the index selection experiment (the COL pigs). The control line (C) was continued with random …

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

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. …

Effects Of Genetic Type And Protein Levels On Growth Of Swine, O.W. Robison, L. L. Christian, R. Goodwin, R. K. Johnson, J. W. Mabry, R. K. Miller, M. D. Tokach

Department of Animal Science: Faculty Publications

A total of 1,588 pigs representing six genetic lines were included in this study. These lines were selected to represent a wide range of biological types for appetite, rate and composition of gain, and meat quality traits. Each line was fed four different diets differing in lysine content. Barrows and gilts were used in the experiment, and pigs were randomly assigned to come off test at one of three weights (113.6, 131.8, or 150 kg). Rates of increase in weight, backfat thickness, and longissimus muscle area were essentially linear. Genetic type and diet influenced (P < .05) rates of change in weight, backfat thickness, and longissimus muscle area and 10th rib fat depth, carcass longissimus muscle area, and dressing percentage. Genetic type × diet interactions were significant for weight change and 10th rib fat. As off-test-weight class increased fat and longissimus muscle area increased in linear fashion. In general, interactions associated with diet resulted from feeding the diet lowest in lysine. There was little evidence of genetic type × diet interactions. If those interactions that tested significant are real, they are a result of extremes in both genetic type (high fatness) and lysine level (low). Slaughtering pigs at heavier weights results in no change in rate of gain over the feeding period and linear increases in longissimus muscle area and backfat thickness.

Comparison Of Plasma Fsh Concentration In Boars And Gilts From Lines Selected For Ovulation Rate And Embryonal Survival, And Litter Size And Estimation Of (Co)Variance Components For Fsh And Ovulation Rate, R. K. Johnson, J. J. Ford

Department of Animal Science: Faculty Publications

The objective of this research was to determine whether plasma concentration of FSH was genetically correlated with ovulation rate and thus was a useful trait for indirect selection. Blood samples were collected from 619 animals from five lines of pigs. Line I was selected for increased index of ovulation rate and embryonal survival, and Line C was its randomly selected control. Pigs sampled from Lines I and C were from generations 12 and 13. Pigs from three additional lines that were derived from eighth-generation pigs of Lines I and C also were used. These lines were Line C2, a randomly …

Rapid Communication: Porcine Vitamin D-25-Hydroxylase Maps To Chromosome 5, Daniel C. Ciobanu, R. K. Raven, M. F. Rothschild, N. H. Bell

Department of Animal Science: Faculty Publications

Locus Name. Vitamin D-25-hydroxylase.

Species. Sus scrofa.

Locus Symbol. CYP25.

Source of Primers. PCR primers were designed from the published sequence for porcine vitamin D-25-hydroxylase (CYP25) cDNA (GenBank accession no. Y16417). The position of the forward and reverse primers corresponds to 506 to 530 bp and 830 to 854 bp, respectively, of the cDNA. The primer pair amplified a 348-bp fragment of the cDNA and an 862-bp fragment from the pig genomic DNA. The 862-bp fragment (Gen- Bank accession no. AF284378) was subcloned into a pNoTA vector and identity was confirmed by sequencing. Genomic sequences from 1 to 74, …

Comparison Of Plasma Fsh Concentration In Boars And Gilts From Lines Selected For Ovulation Rate And Embryonal Survival, And Litter Size And Estimation Of (Co)Variance Components For Fsh And Ovulation Rate, J. D. Cassady, Rodger K. Dennison, J. J. Ford

Department of Animal Science: Faculty Publications

The objective of this research was to determine whether plasma concentration of FSH was genetically correlated with ovulation rate and thus was a useful trait for indirect selection. Blood samples were collected from 619 animals from five lines of pigs. Line I was selected for increased index of ovulation rate and embryonal survival, and Line C was its randomly selected control. Pigs sampled from Lines I and C were from generations 12 and 13. Pigs from three additional lines that were derived from eighth-generation pigs of Lines I and C also were used. These lines were Line C2, a randomly …

Responses In Ovulation Rate, Embryonal Survival, And Litter Traits In Swine To 14 Generations Of Selection To Increase Litter Size, Rodger K. Johnson, Merlyn K. Nielsen, David S. Casey

Department of Animal Science: Faculty Publications

Eleven generations of selection for increased index of ovulation rate and embryonal survival rate, followed by three generations of selection for litter size, were practiced. Laparotomy was used to count corpora lutea and fetuses at 50 d of gestation. High-indexing gilts, approximately 30%, were farrowed. Sons of dams in the upper 10% of the distribution were selected. Selection from Generations 12 to 14 was for increased number of fully formed pigs; replacements were from the largest 25% of the litters. A randomly selected control line was maintained. Responses at Generation 11 were approximately 7.4 ova and 3.8 fetuses at 50 …

Genetics Of The Interval From Weaning To Estrus In First-Litter Sows: Correlated Responses, J. Ten Napel, T. H. E. Meuwissen, R. K. Johnson, E. W. Brascamp

Department of Animal Science: Faculty Publications

The objective of this study was to evaluate relationships between rebreeding performance and growth performance (n = 3,777 gilts) and rebreeding performance and reproductive performance (n = 2,242 sows). Our data were from a selection experiment for shorter intervals from weaning to estrus after the first parity (IWE), involving Dutch Landrace pigs, in which a selection line and a control line without selection were maintained for eight generations. Relationships were evaluated before and after transforming IWE to normal interval (NI; IWE &#; 7 d), prolonged interval (PI; IWE > 7 d), and incidence of a prolonged interval (INC). Heritabilities of NI, …

Evidence For Quantitative Trait Loci Affecting Ovulation Rate In Pigs, Thomas A. Rathje, G. A. Rohrer, R. K. Johnson

Department of Animal Science: Faculty Publications

Fifty-five microsatellite markers were scored in an F₂ population of pigs (n = 114 females) developed at the University of Nebraska. The population was produced by crossing a line previously selected for 10 generations using an index of ovulation rate and embryonal survival and a line selected at random. The lines were from a common base population and differed by 6.7 ovulations and 3.1 fetuses at 50 d of gestation. Ovulation rate and number of fully formed and mummified pigs were recorded for each female. Data were analyzed with regression models that included random animal effects. Likelihood-ratio tests were …

Growth Of Testes And Testicular Morphology After Eight Generations Of Selection For Increased Predicted Weight Of Testes At 150 Days Of Age In Boars, R. R. Harder, D. D. Lunstra, R. K. Johnson, Roman L. Hruska

Department of Animal Science: Faculty Publications

Weights of testes and epididymides, body weight, and morphometric measurements of testicular tissue of 75 boars of a line selected for eight generations for predicted weight of testes at 150 d of age and 75 boars of a randomly selected control line were used to evaluate the effects of selection on testicular development at 70, 100, 130, 160, and 450 d of age (n = 15 boars per line per age). Body weights for boars of the select and control line did not differ (P <.05) and the shape of the body growth curve was similar for both lines. Boars of the select line had larger testes than control boars at each age (P < .05), but there was a significant line x age interaction. The percentage increase of the select line mean over the control mean for weight of testes was 37% at 70 d, a maximum of 120% at 100 d, and 25% at 450 d. The percentage of the testes made up of seminiferous tubules differed between lines (P <.01). Lines had similar means of approximately 28% at 70 d and 71% at 450 d, but the mean for the select line was larger between 100 and 160 d of age; the greatest difference was 11.6% (control = 43.7, select = 55.3%) at 100 d. After 70 d of age, select-line boars had a greater percentage of seminiferous tubules with lumens that contained elongated spermatids (P <.lo). The proportion of the testes occupied by Leydig cells was greatest at 70 d, declined sharply between 70 and 130 d with a sharper decline in select-line boars, and then declined more gradually from 130 to 450 d of age. We conclude that selection for weight of testes at 150 d resulted in lower age at puberty for boars of the select line.

Growth Of Testes And Testicular Morphology After Eight Generations Of Selection For Increased Predicted Weight Of Testes At 150 Days Of Age In Boars, R. R. Harder, D. D. Lunstra, R. K. Johnson, Roman L. Hruska

Department of Animal Science: Faculty Publications

Weights of testes and epididymides, body weight, and morphometric measurements of testicular tissue of 75 boars of a line selected for eight generations for predicted weight of testes at 150 d of age and 75 boars of a randomly selected control line were used to evaluate the effects of selection on testicular development at 70, 100, 130, 160, and 450 d of age (n = 15 boars per line per age). Body weights for boars of the select and control line did not differ (P <.05) and the shape of the body growth curve was similar for both lines. Boars of the select line had larger testes than control boars at each age (P < .05), but there was a significant line x age interaction. The percentage increase of the select line mean over the control mean for weight of testes was 37% at 70 d, a maximum of 120% at 100 d, and 25% at 450 d. The percentage of the testes made up of seminiferous tubules differed between lines (P <.01). Lines had similar means of approximately 28% at 70 d and 71% at 450 d, but the mean for the select line was larger between 100 and 160 d of age; the greatest difference was 11.6% (control = 43.7, select = 55.3%) at 100 d. After 70 d of age, select-line boars had a greater percentage of seminiferous tubules with lumens that contained elongated spermatids (P <.l0). The proportion of the testes occupied by Leydig cells was greatest at 70 d, declined sharply between 70 and 130 d with a sharper decline in select-line boars, and then declined more gradually from 130 to 450 d of age. We conclude that selection for weight of testes at 150 d resulted in lower age at puberty for boars of the select line.

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 …

Effect Of Fat Source In Receiving Diets And Reduced Nocturnal Temperatures On Commingled Feeder Pig Performance, Michael C. Brumm, Ernest R. Peo, Jr.

Department of Animal Science: Faculty Publications

Three experiments using 864 crossbred feeder pigs were conducted to determine the effects of fat sources and a feed flavor in 3-wk receiving diets and a reduced nocturnal temperature regimen on commingled feeder pig performance. In Exp. 1, there was no response to a feed flavor on overall ADG or ADFI. Commingled pigs offered receiving diets containing 5% blended vegetable oil (5B) or 5% tallow (5T) did not differ in overall ADG (.61, .63 vs .61 kg/d) and gain:feed (.315, .307, .310) compared with pigs offered corn-soy diets.

Animal Model Estimation Of Genetic Parameters And Response To Selection For Litter Size And Weight, Growth, And Backfat In Closed Seedstock Populations Of Large White And Landrace Swine, Jose Bento S. Ferraz, Rodger K. Johnson

Department of Animal Science: Faculty Publications

Records from 2,495 litters and 14,605 Landrace and Large White pigs from two farms, but established from the same base population and run as replicated selection lines, were analyzed. Selection within herd was on estimated breeding values weighted by economic values. Animal models and REML procedures were used to estimate genetic, phenotypic, and environmental parameters for the number of pigs born alive (NBA), litter weight at 21 d (LW), average daily gain from approximately 30 to 104 kg (AD GI, and backfat thickness adjusted to 104 kg (BF). Random animal genetic effects ( 01, permanent (NBA and LW) or litter …

Changes In Ovulation Rate, Uterine Capacity, Uterine Dimensions, And Parity Effects With Selection For Litter Size In Swine, Luis L. T. Gama, R. K. Johnson

Department of Animal Science: Faculty Publications

This study was conducted with random samples of pigs of a line (LS) selected for eight generations for litter size and a randomly selected control line (RS) in the Nebraska Gene Pool population and of crosses of these lines with a Large White- Landrace composite line (I) that was selected for an index of ovulation rate and embryonic survival to 50 d of gestation. Two experiments were done to obtain information on ovulation rate, uterine dimensions, and uterine capacity. In Exp. 1, 103 gilts were slaughtered 9 to 16 d after their second estrus to obtain reproductive tracts for evaluation …