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Biomedical subjects

L D Young

Publications and source records attributed to L D Young.

At least 19 recordsLinked to original sources
PubMed2002

Heterosis and recombination effects on pig growth and carcass traits.

The primary objective was to estimate breed, heterosis, and recombination effects on growth and carcass traits of two different four-breed composite populations of pigs. Experiment 1 (Exp. 1) included purebred and crossbred pigs originating from Yorkshire, Landrace, Large White, and Chester White breeds, and Experiment 2 (Exp. 2) included pigs from Duroc, Hampshire, Pietrain, and Spot breeds. Data were recorded on purebred pigs, two-breed cross pigs, and pigs from generations F1 through F6, where F1 pigs were the first generation of a four-breed cross. Pig weights were recorded at birth and at 14, 28, 56, 70, and 154 d of age. Average daily gain was calculated for intervals between weights, and ultrasonic backfat measurements (A-mode) were taken at 154 d of age. Feed intake was measured between 70 and 154 d of age on mixed pens of boars and barrows. Carcass backfat, length, and loin muscle area were measured on barrows at slaughter. Mixed-model analyses were done separately by experiment, fitting an animal model. Fixed effects included farrowing group and sex for growth traits and farrowing group for carcass traits. For ADFI, a weighted mixed-model analysis was done fitting farrowing group as a fixed effect, sire nested within farrowing group as a random effect, and weighting each observation by the number of pigs in each pen. To test feed efficiency, a second analysis of ADFI was done adding ADG as a covariate in the previous model. Included as covariates in all models were direct, maternal, and maternal grandam breed effects, direct and maternal heterosis effects, and a direct recombination effect. Recombination is the breakup of additive x additive epistatic effects present in purebreds during gamete formation by crossbred parents. Effects of direct heterosis significantly increased weights at birth, 14, 56, 70, and 154 d of age in Exp. 1. Effects of direct heterosis significantly increased ADG from birth to 14, 28 to 56, and 70 to 154 d of age in Exp. 1. In Exp. 2, effect of direct heterosis significantly increased weights and ADG at all ages. In Exp. 1, recombination significantly reduced loin muscle area. In Exp. 2, recombination significantly increased weights at birth, 14, 28, and 56 d, ADFI from 70 to 154 d, and ADFI adjusted for ADG. The correlation between maternal heterosis and recombination effects for all traits in Exp. 1 and Exp. 2 was approximately -0.90. Maternal heterosis and recombination effects were estimable, but greatly confounded.

Adipose Tissue↗
PubMed2002

Heterosis and recombination effects on pig reproductive traits.

The objective was to estimate breed, heterosis, and recombination effects on pig reproductive traits in two different four-breed composite populations. Breeds included Yorkshire, Landrace, Large White, and Chester White in Exp. 1 and Duroc, Hampshire, Pietrain, and Spot in Exp. 2. Data were recorded on purebred pigs, two-breed cross pigs, and pigs from generations F1 through F6, where F1 pigs were the first generation of a four-breed cross. Litter traits were considered a trait of the gilt. There were 868 first parity litters in Exp. 1 and 865 in Exp. 2. Direct heterosis significantly increased sow weight at 110 d of gestation and litter weight at 14 and 28 d (weaning) in both experiments. Direct heterosis significantly increased number of nipples, weight at puberty, lactation weight loss, litter size, and litter birth weight in Exp. 2. Gestation length in Exp. 1 and age at puberty in Exp. 1 and Exp. 2 were significantly decreased by direct heterosis. Maternal heterosis significantly increased age at puberty in Exp. 2 and decreased sow weight at 110 d of gestation in Exp. 1. Recombination significantly increased sow weight at 110 d of gestation and tended to increase total number born and litter birth weight in Exp. 1. Recombination significantly decreased age at puberty in Exp. 2. Litter heterosis significantly increased number of pigs at 14 and 28 d; litter weights at birth, 14, and 28 d; and tended to increase lactation weight loss in Exp. 1. Litter heterosis decreased litter size in Exp. 2. Maternal heterosis and recombination effects had a sampling correlation of -0.97 in Exp. 1 and -0.91 in Exp. 2 for number of fully formed pigs. Therefore, maternal heterosis and recombination effects were summed, and their net effect was tested. This net effect tended to increase number of nipples, lactation weight loss, and litter birth weight and significantly increased number of fully formed pigs in Exp. 1. Direct, maternal, and litter heterosis and recombination effects significantly influenced reproductive traits.

Animals↗
PubMed2000

Kinetics of cellular and cytokine responses in a chimeric mouse model for the study of staphylococcal enterotoxin B pathogenesis.

The mechanisms by which superantigens, such as staphylococcal enterotoxin B (SEB), contribute to microbial pathogenicity have been poorly defined. The study of such pathogenic processes has been hampered by the lack of an adequate animal model. We utilized a previously described murine chimeric model to determine the cytokines and cell populations that might be involved in SEB toxicity. In the absence of bone marrow transplantation (BMT), all total body irradiated (TBI) mice died, while all transplanted mice survived up to 6 months. Compared with non-TBI and non-BMT mice, chimeric mice had an increased percentage of CD11b (Mac-1)-positive splenocytes (17 vs. 59%, P < 0.05) and decreased CD45R-positive (B) cells (33 vs. 6%, P < 0.05) at 6 weeks after BMT. The relative numbers of splenocyte CD4 and CD8 cells were similar in chimeric and normal mice. Susceptibility of chimeric animals to 10 or 100 microg SEB was time-dependent: no mice challenged at 2 weeks post-BMT died, but 15% of mice challenged at 4 weeks and 50% of those challenged at 6-8 weeks died. Compared with TBI and non-BMT C3H/HeJ mice, SEB-challenged chimeric mice at 6-8 weeks had (1) increased splenocyte mRNA expression for: IFN-gamma (3.5 x optimally at 1 h), TNF-alpha (6.5 x at 2 h), IL-6 (4.8 x at 4 h), IL-1beta (8.4 x at 4 h), IL-2 (4.7 x at 4 h), and IL-10 (3 x at 16 h), and (2) increased and earlier peak serum levels of IFN-gamma, IL-6, IL-1beta and IL-2, but no increase in serum TNF-alpha or IL-4. These data support the hypothesis that the decreased percentage of B cells and increased macrophages in chimeric mice lead to enhanced T cell-macrophage interactions after SEB administration and a lethal burst of T cell and macrophage cytokine release. This model will provide insight into cell populations and mechanisms that mediate superantigen-induced toxicity.

Animals↗
PubMed2000

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: I. Effects of ram breed on productivity of ewes of two crossbred populations.

Effects of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds for performance as sires were estimated in the initial phase of a comprehensive evaluation of these breeds as contributors to sheep crossbreeding systems. Objectives were to evaluate the effects of ram breed, ewe breed, season of mating, and two-way interactions. Rams from the five breeds were single-sire-mated with ewes from two breed types to produce lambs over a 3-yr period. Ewes were assigned to one of three distinct 35-d mating seasons initiated each year in August, October, and December. A different sample of six rams per breed was used each year across all three seasons, and each ram was penned with ewes of both breeds. Traits evaluated and number of ewe records were conception rate and litter weaning weight per ewe exposed (n = 3,261) and number born, litter birth weight, average birth weight, number weaned, and litter weaning weight per ewe lambing (n = 2,751). Ram breed and ewe breed interacted (P < .01) for conception rate and litter weaning weight per ewe exposed, implicating mating preferences, particularly of Romanov rams. In mixed groups of ewes exposed to Romanov rams, conception rate was 12.7% lower and litter weight weaned was 8.4 kg lower in the ewe breed presumably less preferred for mating by the rams. On a per ewe exposed basis, Romanov-sired litters produced either the largest or the smallest values for litter weaning weight, depending on the breed of ewe. Effects of ram breed on number born and litter birth weight interacted (P < .05) with season of mating. The largest litters within each ram breed were associated with the October mating season. Montadale and Romanov rams sired larger and heavier litters from August matings than from December matings, whereas the opposite was true for Dorset-sired litters. Texel- and Finnsheep-sired litters were similar in size and weight from August and December matings. Breed of ram differences affected per ewe lambing productivity measurements (P < .01). Differences between ram breeds for ewe productivity were noted, with increased number born and improved survival of crossbred progeny to weaning for Romanov-sired litters. These results may have implications for using these ram breeds as sires in different crossbreeding systems. Structured mating systems or the creation of new composite populations involving these breeds could be used to match the resources, environment, and market of specific production situations.

Animals↗
PubMed1998

Recombinant human interleukin-11 in experimental Pseudomonas aeruginosa sepsis in immunocompromised animals.

The therapeutic potential of recombinant human interleukin-11 (rhIL-11) was tested in a neutropenic rat model that mimics the clinical consequences of myelosuppressive chemotherapy complicated by Pseudomonas aeruginosa sepsis. rhIL-11-treated animals (150 micrograms/kg intravenously every 24 h for 3 days) had reduced endotoxin levels (P < .05) and less pulmonary edema fluid (P < .001) and were protected (P < .01) against thinning and necrosis of the intestinal mucosa compared with the control group. The survival rate in rhIL-11-treated animals was 40% (19/47), whereas it was 0 (0 of 19) in the control group (P < .01). The addition of ciprofloxacin (10 mg/kg every 12 h) resulted in a survival rate of 9 (60%) of 15, while the combination of rhIL-11 and ciprofloxacin resulted in 100% survival (15/15; P < .05). These results indicate that rhIL-11 supports mucous membrane integrity of the alimentary tract and decreases the systemic inflammatory response to experimental gram-negative infection in immunocompromised animals.

Animals↗
PubMed1998

Covalent polymyxin B conjugate with human immunoglobulin G as an antiendotoxin reagent.

Polymyxin B (PMB) is a cyclic decapeptide antibiotic which also binds and neutralizes endotoxin. Unfortunately, PMB can be considerably nephrotoxic at clinically utilized doses, thereby limiting its utility as a therapeutic antiendotoxin reagent. We sought to change the pharmacokinetics and toxicity profile of PMB by covalently linking it to a human immunoglobulin G (IgG) carrier. Conjugates of PMB with IgG were prepared by EDAC [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide]-mediated amide formation. Analysis by dot enzyme-linked immunosorbent assay with an anti-PMB monoclonal antibody showed that the purified conjugate contained bound PMB. The IgG-PMB conjugate reacted with lipid A and J5 lipopolysaccharide in Western blot assays in a manner comparable to that of whole antiserum with anti-lipid A reactivity; unconjugated IgG had no reactivity. The PMB bound in the conjugate retained its endotoxin-neutralizing activity compared to that of unbound PMB as evidenced by its dose-dependent inhibition of tumor necrosis factor release by endotoxin-stimulated human monocytes in vitro; unconjugated IgG had no activity. By this assay, the PMB-IgG conjugate was determined to have approximately 3.0 microg of bound functional PMB per 100 microg of total protein of conjugate (five molecules of PMB per IgG molecule). The PMB-IgG conjugate was also bactericidal against clinical strains of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae relative to unconjugated IgG with MBCs of <4 microg of conjugate per ml for each of the tested strains. The conjugate appeared to be nontoxic at the highest doses deliverable and provided statistically significant protection from death to galactosamine-sensitized, lipopolysaccharide-challenged mice in a dose-dependent fashion when administered prophylactically 2 h before challenge. However, neither free PMB nor the PMB-IgG conjugate could protect mice challenged with endotoxin 2 h after administration. This suggests that these reagents can play a role in prophylaxis but not in therapy of sepsis. These experiments demonstrated that the PMB-IgG conjugate retains bound yet functional PMB as evidenced by its endotoxin-neutralizing activity both in vitro and in vivo. Further work is required to define the role that this or related conjugate compounds may play in the prophylaxis of endotoxin-mediated disease.

Anti-Bacterial Agents↗
PubMed1998

Survival, body weights, feed efficiency, and carcass traits of 7/8 White Composite and 1/8 Duroc, 1/8 Meishan, 1/8 Fengjing, or 1/8 Minzhu pigs.

Pigs were the progeny of White Composite boars mated to gilts that were either 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu and the remainder 3/4 White Composite. One-eighth Meishan and 1/8 Fengjing pigs averaged approximately .5 more nipples than 1/8 Duroc pigs and .2 more nipples than 1/8 Minzhu pigs (P < .05), respectively. Duroc, Meishan, and Minzhu crosses did not differ (P > .05) for survival at birth or at 14 and 28 d. Fengjing crosses had a lower survival rate (P < .05) at all three ages than Duroc and Meishan crosses. Duroc crosses were heavier (P < .05) than Chinese crosses at birth. At 56 d, Duroc and Meishan crosses did not differ (P > .05) for BW, but both were heavier (P < .05) than Minzhu crosses. Body weight at 70 d did not differ significantly (P > .05) among breed types. Duroc crosses were heavier (P < .05) than any of the Chinese crosses at 98, 126, and 154 d of age. At 154 d, Fengjing crosses were lighter (P < .05) than Meishan or Minzhu crosses. The effect of breed type was not detected for average probe backfat thickness of gilts at 99.7 kg. Duroc crosses consumed the most feed, and Fengjing crosses consumed the least during each interval and during the total period (P < .05). Feed consumption of Meishan and Minzhu crosses was intermediate to and significantly (P < .05) different from that of Duroc and Fengjing crosses. At 184 d of age, breed types did not differ (P > .16) for measures of carcass fat thickness, marbling score, color score, and firmness score. At 184 d of age, weights of all carcass cuts were heavier (P < .05) for Duroc than for Chinese crosses with the exception of untrimmed loin weight of Minzhu crosses. There were few significant differences among breed types when carcass traits were compared at a constant carcass weight, although Duroc crosses generally were superior. Relative to similar Duroc crosses, these results suggest that 1/8 Chinese pigs would grow less rapidly (P < .05) and produce less weight of trimmed lean cuts at a constant carcass weight.

Age Factors↗
PubMed1998

Reproduction of 3/4 White Composite and 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu gilts and sows.

Females were either 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu, and the remainder were 3/4 White Composite. A greater percentage of Fengjing crosses reached puberty than Duroc or Minzhu (P < .05), and Meishan crosses were intermediate and not different (P > .05) from other breed types. After adjusting for differences in percentage detected owing to termination of observation for estrus, breed types ranked Fengjing, Meishan, Minzhu, and Duroc from youngest to oldest at puberty with approximately 14 d between adjacent breed types. Meishan and Fengjing crosses had a greater (P < .05) ovulation rate than Minzhu or Duroc crosses. With the exception of number of fetuses at 100 d and average fetal weight at 60 d, differences among breed types were not detected (P > .05) for litter or uterine traits measured on gilts slaughtered at 60 or 100 d of gestation. Total number of pigs born was greater (P < .05) for 1/4 Fengjing than for 1/4 Duroc gilts. Gestation length, number born alive, number weaned, litter birth weight, or litter weaning weight for gilts did not differ (P > .05) among breed types. Duroc crosses were heavier (P < .01) than Chinese crosses at d 1 and 28 after farrowing, but breed types did not differ (P > .05) for backfat thickness at those times. Breed types did not differ (P > .05) for the ratio of litter gain from 0 to 28 d/total Mcal or any of the component traits in the ratio. Postweaning estrus activity, conception rate, and litter and uterine traits of sows bred for second parity were not affected (P > .05) by breed type. These analyses indicate that crossbred gilts containing 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu will reach puberty earlier, have larger litters, and weigh less at first parity than gilts containing 1/4 Duroc, but they do not have any significant advantage in litter size at second parity.

Animals↗
PubMed1997

Genetic analysis of discrete reproductive traits in sheep using linear and nonlinear models: I. Estimation of genetic parameters.

Repeated records on fertility, litter size, and ovulation rate of Rambouillet ewes and on fertility and litter size of Finnsheep ewes were used to estimate heritabilities and repeatabilities with linear and nonlinear sire and animal models. Linear sire (LSM) and animal models were used with all traits. Nonlinear models were the threshold, Poisson, and negative binomial. Threshold sire (TSM) and animal models were used with all traits. Litter size and ovulation rate were analyzed also with Poisson sire and animal models and with negative binomial sire and animal models. Variance components for linear models were estimated using REML; in the threshold, Poisson, and negative binomial, they were estimated using approximate marginal maximum likelihood. Poisson and negative binomial analyses yielded results difficult to interpret due to problems in variance component estimation. Animal models resulted in slightly greater estimates of heritability for fertility than did sire models, but ovulation rate heritability estimates from sire models were much greater than estimates form animal models. Differences between sire and animal models for heritability estimates for litter size were not consistent. Threshold models resulted in higher heritability estimates for all traits in both breeds and with both sire and animal models. In general, repeatabilities were consistent across models. For example, LSM (TSM) repeatabilities were .10 (.14) for fertility, .20 (.25) for litter size, and .25 (.29) for ovulation rate in the Rambouillet, and .17 (.17) for fertility and .11 (.13 for litter size in the Finnsheep.

Aging↗
PubMed1997

Genetic analysis of discrete reproductive traits in sheep using linear and nonlinear models: II. Goodness of fit and predictive ability.

The performance of linear and nonlinear sire and animal models in the analyses of reproductive traits (fertility, litter size, and ovulation rate) in two sheep populations (Rambouillet and Finnsheep) was compared in terms of goodness of fit and predictive ability. Linear sire (LSM) and animal (LAM) models were used with all traits. Nonlinear models were the threshold, Poisson, and negative binomial. Threshold sire (TSM) and animal (TAM) models were also used with all traits. Litter size and ovulation rate were analyzed also with Poisson and negative binomial sire (PSM and NBSM, respectively) and animal (PAM and NBAM, respectively) models. Variance components were those reported in the companion article. For PAM a new set of variance components derived from estimates found with the linear animal model also was used (PAM-L). Mean squares error (MSE) and correlations between fitted and observed values were used to assess goodness of fit. Predictive ability was assessed by partitioning the data sets for the different traits into two subsets with the restriction that all levels of fixed effects were represented in each subset. Parameters from one subset were employed to predict observations in the other, and then MSE and correlations between observed and predicted values were used as criteria for model comparison. Within estimation procedure, breed, and trait, goodness of fit of sire and animal models was similar. Linear and threshold models resulted in similar fit, and both outperformed Poisson and negative binomial models. In terms of predictive ability, linear and threshold models performed only slightly better than Poisson and negative binomial models. Goodness of fit and predictive ability generally were better when models included permanent environmental effects.

Animals↗
PubMed1996

Potential hazards of combination immunotherapy in the treatment of experimental septic shock.

Using an actual infection model of Pseudomonas aeruginosa sepsis in neutropenic rats, the potential utility of a combination anticytokine approach for the treatment of sepsis was tested. A dimeric tumor necrosis factor binding protein (TNF-BP) consisting of two soluble recombinant human TNF type 1 receptors linked with polyethylene glycol was used with recombinant human interleukin-1 receptor antagonist (IL-1ra). Despite having levels of bacteremia and endotoxemia similar to the control group (survivors, 0/18), 30% of IL-1ra-treated animals survived (P < .05); 31% of TNF-BP-treated animals survived (P < .01). Unexpectedly, the combination of IL-1ra plus TNF-BP proved to be uniformly fatal (survivors, 0/20). Endotoxin (P < .0001) and bacteremia (P < .01) levels were >10-fold higher than levels in animals treated with IL-1ra alone, TNF-BP alone, or placebo. Disseminated microabscesses in major organs were found in animals treated with combination immunotherapy. Combination anticytokine therapy may exacerbate systemic infection and worsen outcome in experimental sepsis.

Animals↗
PubMed1995

Decreases in health care resource utilization in patients with rheumatoid arthritis following a cognitive behavioral intervention.

We previously reported the efficacy of a multicomponent cognitive-behavioral intervention including biofeedback to decrease pain, affective distress, and objective measures of disease activity in patients with rheumatoid arthritis (RA). In the present article we report evidence that this intervention is associated with reductions in RA-related clinic visits and days hospitalized as well as reductions in the costs of these medical services. Data were independently and objectively collected over an 18-month interval as part of a controlled group outcome study. The importance of documenting economic as well as clinical benefits of our treatments in specific patient populations is noted.

Arthritis, Rheumatoid↗
PubMed1995

Factors associated with participation in a preventive cardiology service by patients with coronary heart disease.

A free preventive cardiology service for patients and their asymptomatic family members was established at a large teaching hospital in the southeastern United States to provide medical triage and risk reduction counseling for prevention of coronary heart disease. Patients and families were informed about the service and invited to attend during a personal visit from members of the preventive cardiology consultation service. Our study was designed to explore determinants of decisions to attend the clinic. We conducted telephone interviews with 62 consecutive patients to collect data on individual perceptions of health risks, factors that modify perceptions of health risks and ability to make behavior changes, and actions taken to reduce risk of disease. Of the 62 patients interviewed, 39% had attended the clinic. Patients hospitalized for myocardial infarction or bypass surgery were more likely to attend the clinic than those who had angioplasty or catheterization without bypass surgery.

Adult↗
PubMed1995

Survival, body weights, feed efficiency, and carcass traits of 3/4 white composite and 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu pigs.

Pigs were the progeny of White Composite (WC) boars mated to F1 Duroc x WC, Meishan x WC, Fengjing x WC, and Minzhu x WC gilts. Meishan and Fengjing crosses had more (P < .05) nipples than Duroc and Minzhu crosses. Meishan and Minzhu crosses had a higher survival rate at birth (P < .05) than Duroc and Fengjing crosses, but breed types did not differ significantly (P approximately .29) for survival to 14 or 28 d of age. Duroc crosses were heavier (P < .05) than Fengjing and Minzhu crosses at 0, 28, 56, 70, 98, 126, and 154 d of age; they were heavier (P < .05) than Meishan crosses at 0, 28, 98, 126, and 154 d of age. Chinese crosses had similar weights at most ages, although Meishan crosses were heavier (P < .05) than Fengjing and Minzhu crosses at 126 and 154 d of age. Breed types did not differ significantly (P approximately .27) for feed efficiency during the nursery period. Over the entire finishing period, Duroc-cross gilts (.3310) were less efficient (P < .05) than Meishan (.3436), Fengjing (.3454), or Minzhu crosses (.3466); among barrows Meishan crosses (.3176) were least efficient (P < .05), Fengjing crosses (.3263) were most efficient (P < .05), and Duroc (.3211) and Minzhu (.3209) were intermediate but not significantly different from the Meishan or Fengjing crosses. At a constant age, Duroc crosses had longer carcasses, greater longissimus muscle area, and heavier slaughter weight, carcass weight, and weight of untrimmed cuts and trimmed cuts than the Chinese crosses (P < .05). There were few significant differences among breed types for carcass traits at a constant carcass weight. Results show that, relative to one-half Duroc females, incorporation of one-half Chinese females into a crossbreeding program will result in progeny with a significant decrease in rate of growth (approximately 9% for weight at 154 d of age) and a small, nonsignificant decrease in yield of trimmed lean cuts (approximately 5%) at a constant carcass weight.

Animal Feed↗
PubMed1995

Reproduction of F1 Meishan, Fengjing, Minzhu, and Duroc gilts and sows.

Gilts were the progeny of eight Duroc, nine Meishan, eight Fengjing, and seven Minzhu boars mated to composite (1/4 Chester White, 1/4 Landrace, 1/4 Large White, and 1/4 Yorkshire) females. Age at puberty was youngest (P < .05) for Meishan and Fengjing crosses followed by Minzhu crosses and then Duroc crosses. Fengjing crosses had a higher (P < .05) ovulation rate than Meishan or Minzhu crosses, which had a higher (P < .05) ovulation rate than Duroc crosses. Meishan and Fengjing crosses had larger (P < .05) litters than Duroc crosses at 60 and 100 d of gestation, at birth, and at weaning. Minzhu crosses also had larger (P < .05) litters than Duroc crosses at all stages but were significantly lower than Meishan and Fengjing crosses only for litter size at 100 d of gestation. Duroc crosses were heavier (P < .05) at farrowing than all three Chinese crosses. Breed groups differed (P < .05) for backfat thickness at weaning but not at farrowing. Duroc crosses were the least efficient (P < .05) in converting feed energy into litter gain from birth to weaning; Fengjing crosses were less efficient (P < .05) than Minzhu crosses but neither differed significantly from the intermediate value of the Meishan crosses. Chinese crosses returned to estrus sooner after weaning (P < .05) than Duroc crosses. Ovulation rate at second parity was highest for Fengjing crosses followed by Meishan, Duroc, and Minzhu crosses; difference among nonadjacent means were significant (P < .05). Differences among crosses were not large or significant for number of fetuses at 100 d of gestation at second parity. Results indicate Meishan and Fengjing can be used to produce crossbred gilts that have a higher level of reproductive performance than Duroc crossbred gilts; the reproductive performance of Minzhu crosses would be intermediate. However, the Chinese crosses would not be expected to have an advantage in litter size at second parity.

Animals↗
PubMed1994

Concentrations of inorganic elements in milk of sows selected for high and low serum cholesterol.

Comprehensive information on the composition of the whole spectrum of essential inorganic elements in sow milk is very limited. The objectives of this study were to measure concentrations of major and trace mineral elements in milk of third-generation sows selected for high (H) or low (L) serum cholesterol concentrations at 8 wk of age and to determine correlations between concentrations of milk cholesterol and major and trace mineral elements in sow milk. Twenty-one H and 21 L and 8 contemporary unselected control (U) Chester White x Landrace x Large White x Yorkshire crossbred sows were milked on d 20 or 21 of their first lactation. A standard corn and soybean meal-based diet was fed to all sows during pregnancy and lactation. There were no differences among the sow groups in milk concentrations of Ca, K, Mg, Na, and P, indicating that the genetic selection for serum cholesterol did not affect major mineral contents of the milk. Concentration of S in milk of the H sows was significantly (P < .05) higher than that of the U sows. Effects of genetic group were significant for concentrations of B, Al, Cu, and Mn in the milk, but not for Mo and Zn concentrations. Milk cholesterol concentration was negatively correlated with milk Al (P < .05), B (P < .01), and Mn (P < .05) for pooled data; there was no relationship between milk cholesterol concentration and that of other mineral elements.

Analysis of Variance↗