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245 results on '"Vazquez, J.M."'

49. Use of frozen-thawed semen aggravates the summer-autumn infertility of artificially inseminated weaned sows in the Mediterranean region

Author

Bolarin, A., Hernandez, M., Vazquez, J.M., Rodriguez-Martinez, H., Martinez, E.A., and Roca, J.

Subjects
Sows -- Physiological aspects, Artificial insemination -- Research, Ovulation -- Research, Zoology and wildlife conservation
Abstract

Improvement of farrowing rate (FR) and litter size (LS) of sows that are AI with frozen-thawed (FT) semen can hardly be reached without identification of the factors behind the high variability seen among trials. Three experiments using weaned (4-d wean-to-estrus interval) multiparous (parity 2 to 7) sows were conducted to evaluate the effect of period of the year on FR and LS of FT-inseminated sows in southern Spain. Sows were grouped into 2 periods of the year: winter-spring (November to April; WS) and summer-autumn (May to October; SA). Ovarian status was monitored by transrectal ultrasonography to record how long before or after ovulation AI was performed (pre-, peri-, or postovulatory AI) and to determine the onset of estrus-to-ovulation interval (EOI). Inseminations were performed using deep intrauterine AI with 1.5 x [10.sup.9] FT sperm per dose. The first experiment was designed to determine the influence of the period of the year on FR and LS of FT semen. Sows (116 in WS and 100 in SA) were AI at 33 and 39 h after the onset of estrus. The period of the year influenced the FR and LS (P < 0.01). Farrowing rate and LS were least in SA (P < 0.05). This pattern of annual variation was similar to that shown by sows on the same farm currently undergoing AI with liquid semen (cervical AI at 12 and 36 h after the onset of estrus with 3 x [10.sup.9] sperm per dose). However, the FR reduction in SA respect to WS was more substantial in sows artificially inseminated with FT (77.6 vs. 50%, P < 0.001) than those artificially inseminated with liquid semen (83.9 vs. 71.8%, P < 0.05). More pre- and less periovulatory AI were performed in SA sows than in WS (P [greater than or equal to]0.05). Experiment 2 was designed to evaluate whether the period of the year influenced EOI. Ovarian status was transrectal ultrasonography scanned every 6 h after the onset of estrus until the end of ovulation (WS: 30; SA: 31 sows). There were more sows with long EOI (>48 h) in SA than in WS (P [greater than or equal to] 0.05). Experiment 3 aimed to improve the reduced FR and LS recorded in SA sows when using FT semen (Exp. 1) by inducing ovulation with eCG + hCG. A single AI with FT semen was performed 5 h before the expected ovulation (55 sows). As a control, spontaneously ovulating sows (n = 53) were FT-inseminated as in Exp. 1. Hormonal induction of ovulation did not improve FR and LS (P > 0.05). In the Spanish Mediterranean area, a longer EOI during SA negatively influenced the FR and LS of weaned sows after AI. This effect was particularly evident when FT semen was use& These findings were not ameliorated by hormonal induction of ovulation. Key words: fertility, frozen-thawed semen, ovulation, season, swine doi: 10.2527/jas.2009-1941

Published
2009

50. A quantitative trait locus genome scan for porcine muscle fiber traits reveals overdominance and epistasis

Author

Estelle, J., Gil, F., Vazquez, J.M., Latorre, R., Ramirez, G., Barragan, M.C., Folch, J.M., Noguera, J.L., Toro, M.A., and Perez-Enciso, M.

Subjects
Quantitative trait loci -- Research, Muscles -- Genetic aspects, Muscles -- Properties, Swine -- Physiological aspects, Swine -- Genetic aspects, Genetic epistasis -- Research, Dominance (Genetics) -- Research, Histochemistry -- Genetic aspects, Meat -- Quality, Meat -- Genetic aspects, Zoology and wildlife conservation
Abstract

Muscle histochemical characteristics are decisive determinants of meat quality. The relative percentage and diameters of the different muscular fiber types influence crucial aspects of meat such as color, tenderness, and ultimate pH. Despite its relevance, however, the information on muscle fiber genetic architecture is scant, because histochemical muscle characterization is a laborious task. Here we report a complete QTL scan of muscle fiber traits in 160 animals from a [F.sub.2] cross between Iberian and Landrace pigs using 139 markers. We identified 20 genome regions distributed along 15 porcine chromosomes (SSC1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and X) with direct and(or) epistatic effects. Epistasis was frequent and some interactions were highly significant. Chromosomes 10 and 11 seemed to behave as hubs; they harbored 2 individual QTL, but also 6 epistatic regions, Numerous individual QTL effects had cryptic alleles, with opposite effects to phenotypic pure breed differences. Many of the QTL identified here coincided with previous reports for these traits in the literature, and there was overlapping with potential candidate genes and previously reported meat quality QTL. Key words: epistasis, muscle fiber, overdominance, pig, quantitative trait locus

Published
2008

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