Heterophil/lymphocyte response of local Spanish breeds of laying hens to cold stress, heat stress, and water restriction.

Environmental challenges may adversely affect poultry production. Autochthonous breeds are particularly valuable in a climate change context because of adaptation to the local environment. The objective of the present study was to determine the impact of cold stress, water restriction, and heat stress on the stress response quantified by the heterophil to lymphocyte ratio (H/L) of ten local Spanish breeds of laying hens.

Failing the four-gamete test enables exact phasing: the Corners' Algorithm.

Background: Failing the four-gamete test for two polymorphic DNA markers is an indication that two or three rather than four haplotypes segregate in the population. The objective of this paper is to show that when just three haplotypes are segregating, all three haplotypes can be fully and unambiguously phase-resolved.

Theory And Methods: The Corners' Algorithm tests the four corners in a 3 × 3 table of two-locus genotypes.

First-degree relationships and genotyping errors deciphered by a high-density SNP array in a Duroc × Iberian pig cross.

Background: Two individuals with a first-degree relationship share about 50 percent of their alleles. Parent-offspring relationships cannot be homozygous for alternative alleles (genetic exclusion).

Methods: Applying the concept of genetic exclusion to HD arrays typed in animals for experimental purposes or genomic selection allows estimation of the rate of rejection of first-degree relationships as the rate at which two individuals typed for a large number of Single Nucleotide Polymorphisms (SNPs) do not share at least one allele.

Vector space algebra for scaling and centering relationship matrices under non-Hardy-Weinberg equilibrium conditions.

Background: Scales are linear combinations of variables with coefficients that add up to zero and have a similar meaning to "contrast" in the analysis of variance. Scales are necessary in order to incorporate genomic information into relationship matrices for genomic selection. Statistical and biological parameterizations using scales under different assumptions have been proposed to construct alternative genomic relationship matrices.

Prospects for sustainability of pig production in relation to climate change and novel feed resources.

Pig production systems provide multiple benefits to humans. However, the global increase in meat consumption has profound consequences for our earth. This perspective describes two alternative scenarios for improving the sustainability of future pig production systems.

Impact of environmental temperature on production traits in pigs.

There is an urgent need to identify the effects of temperature on production traits. This study aimed to determine the impact of pig production in three environments (T = T, T, and T) on growth curve parameters, body weight gain (DBWG), feed intake (DFI), and feed efficiency during the growing, fattening and finishing stages, and on carcass yield of primal cuts (ham, shoulder, and loin) in 158 Duroc × Iberian pigs. Maturation rate was higher in T than in T (P < 0.

Extent of third-order linkage disequilibrium in a composite line of Iberian pigs.

Background: Previous studies on linkage disequilibrium have investigated second order linkage disequilibrium in animal and plant populations. The objective of this paper was to investigate the genome-wide levels of third order linkage disequilibrium in a composite line founded by admixture of four Iberian pig strains. A model for the generation of third order linkage disequilibrium by population admixture is proposed.

Estimation of Recombination Rate and Maternal Linkage Disequilibrium in Half-Sibs.

A livestock population can be characterized by different population genetic parameters, such as linkage disequilibrium and recombination rate between pairs of genetic markers. The population structure, which may be caused by family stratification, has an influence on the estimates of these parameters. An expectation maximization algorithm has been proposed for estimating these parameters in half-sibs without phasing the progeny.

Genotype by environment interaction and breeding for robustness in livestock.

The increasing size of the human population is projected to result in an increase in meat consumption. However, at the same time, the dominant position of meat as the center of meals is on the decline. Modern objections to the consumption of meat include public concerns with animal welfare in livestock production systems.

Haplotype phasing after joint estimation of recombination and linkage disequilibrium in breeding populations.

A novel method for haplotype phasing in families after joint estimation of recombination fraction and linkage disequilibrium is developed. Results from Monte Carlo computer simulations show that the newly developed E.M.

The relationship between feed intake behaviour with intramuscular fat, cholesterol and fatty acid composition in pork.

The aim of this study was to investigate the phenotypic relationship between feed intake (FI) characteristics with intramuscular fat, cholesterol and fatty acid composition in pork. Data were available on 202 Duroc barrows. Intramuscular fatness was positively correlated with a higher percentage of saturated (SFA) and monounsaturated fatty acids (MUFA), a lower percentage of polyunsaturated (PUFA), omega-3 (ω3) and omega-6 (ω6) fatty acids, and a lower ω6/ω3 and P:S ratio (p < 0.

Gene expression in Sinclair swine with malignant melanoma.

Sinclair swine develop an aggressive form of melanoma, which, in many cases, spontaneously regresses after a complete metastatic phase. We used Affymetrix GeneChip® Porcine Genome Arrays consisting of 24 123 probe sets to compare gene expression in white blood cells (WBCs) and various tissues including the liver, lungs, inguinal lymph nodes and spleen harvested from a Sinclair piglet afflicted by melanoma at birth and exhibiting metastatic lesions at weaning (6 weeks) with those from a full-sibling piglet that showed no incidence of melanoma at birth and weaning. The highest number (3489; ∼14%) of significantly upregulated transcripts (fold change in gene expression ≥2.

Maximum likelihood estimation of linkage disequilibrium in half-sib families.

Maximum likelihood methods for the estimation of linkage disequilibrium between biallelic DNA-markers in half-sib families (half-sib method) are developed for single and multifamily situations. Monte Carlo computer simulations were carried out for a variety of scenarios regarding sire genotypes, linkage disequilibrium, recombination fraction, family size, and number of families. A double heterozygote sire was simulated with recombination fraction of 0.

Adaptability of pregnant Merino ewes to the cold desert climate in Nevada.

Grazing ability is difficult to record in animals under free-ranging conditions without sophisticated methods. Alternatively, grazing ability may be indirectly inferred from changes in BW and production characteristics during the grazing period. The present study investigated the effect of grazing on resource-limited rangelands on BW, wool characteristics, and offspring weaning weights in nine hundred five 5/8, 7/8, and fullblood Merino ewes of 2 to 7 yr of age during a grazing period of approximately 2.

Swine leukocyte antigen (SLA) diversity in Sinclair and Hanford swine.

The swine leukocyte antigen (SLA) haplotype B is associated with increased penetrance of the tumor traits in Sinclair swine cutaneous melanoma (SSCM). We established a series of SinclairxHanford swine crosses to facilitate genetic mapping of the tumor-associated loci. In this study, the SLA diversity in the founding animals was characterized for effective selection of maximum tumor penetrance in the pedigrees.

Role of selection and inbreeding on the incidence of cutaneous malignant melanoma in Sinclair swine.

This paper reports the quantitative analysis of the historical database of a herd of Sinclair swine affected by cutaneous malignant melanoma. The herd was under partial and non-systematic selection for melanoma susceptibility (animals having at least one tumour during the first 6 weeks of life). Weighted selection differentials for the number of tumours at birth and the number of tumours at 6 weeks were generally positive and between -0.

Inferring unknown genotypes of sires at codominant deoxyribonucleic acid markers in half-sib families.

Deoxyribonucleic acid from sires is usually not available from experiments aimed at QTL mapping for traits of the dam in cow-calf operations and free range sheep populations. In this study, methods to reconstruct sire genotypes using genotype information from large half-sib progeny were developed. The methods are based on 1) all offspring genotypes are compatible with more than 1 genotype for the sire, but 1 of the genotypes is more likely than the others when comparing the proportion of the different genotypes among offspring with its expected values assuming Mendelian inheritance, or 2) all offspring genotypes are compatible with just 1 possible genotype for the sire in the pedigree.

Combining two-stage testing and interval mapping strategies to detect QTL for resistance to bonamiosis in the european flat oyster Ostrea edulis.

We have identified quantitative trait loci (QTL) in the flat oyster (Ostrea edulis) for resistance to Bonamia ostreae, a parasite responsible for the dramatic reduction in the aquaculture of this species. An F(2) family from a cross between a wild oyster and an individual from a family selected for resistance to bonamiosis was cultured with wild oysters injected with the parasite, leading to 20% cumulative mortality. Selective genotyping of 92 out of a total of 550 F(2) progeny (i.

The value of DNA paternity identification in beef cattle: examples from Nevada's free-range ranches.

The feasibility and economic value of DNA paternity identification were investigated and illustrated using Nevada beef cattle operations. A panel of 15 microsatellites was genotyped in 2,196 animals from 8 ranches with a total of 31,571 genotypes. Probabilities of exclusion for each marker within ranch and across ranches were computed.

Behaviour influences cholesterol plasma levels in a pig model.

Little is known about the relationship between feed intake behaviour and cholesterol levels in humans. This can be attributed to the fact that feed intake behaviour in humans is difficult to assess. The relationships between feed intake, feed efficiency and feed intake behaviour, and cholesterol and triglyceride levels were investigated at an average age of 187 days, in a pig model consisting of 202 Duroc barrows.

Modeling inheritance of malignant melanoma with DNA markers in Sinclair swine.

Cutaneous malignant melanoma in Sinclair swine is a hereditary disease that develops in utero or during the first 6 weeks of life. In many cases, the tumors regress and piglets survive the disease. Two different sets of gene(s) might be involved in the disease: tumor initiator (suppressor) locus or loci and loci affecting the aggressiveness of the disease (number and stage of tumors).

Feeding time and feeding rate and its relationship with feed intake, feed efficiency, growth rate, and rate of fat deposition in growing Duroc barrows.

Because feed is the major cost to pork production, management practices and breeding strategies are aimed at optimizing feed intake. Knowledge about the shape of feed intake and feeding behavior curves may be of interest for optimization of lean meat production. This study investigated trends based on daily measurements of feeding behavior in 200 Duroc barrows, originating from 5 sires and 200 dams, during growth.