The reliability of using different in vitro-derived measures of sperm quality to predict boar fertility was examined. On three occasions during a 20-wk period of breeding, special collections of the first sperm-rich fraction of the ejaculate from six boars were carried out. After in vitro capacitation procedures, three dilutions (5 x 10(5), 1.25 x 10(5), and 3.125 x 10(4) sperm/mL) of these semen samples were used in a standardized in vitro fertilization (IVF) test with oocytes recovered from prepubertal slaughterhouse ovaries and matured in vitro. Routine assessments of sperm motility, concentration, and morphology were also carried out for all collections used for AI during the 20-wk period. Semen from the same ejaculate, processed according to normal commercial practice using the AndroHEP extender, was used to inseminate equal numbers of recently weaned sows with either 3 x 10(9) or 2 x 10(9) total sperm, three times during the estrous period. Data from a total of 444 sows were used to determine boar fertility; between 12 and 54 sows were bred with each semen dose across the six boars. All measures of sperm fertilizing ability in vitro were different among boars (all P < .05) and use of different semen dilutions for IVF allowed further discrimination of apparent sperm quality among boars. The laboratory evaluation of semen collected during the period of breeding indicated effects of boar on ejaculate volume, total number of sperm per ejaculate, motility, and the percentage of sperm with normal morphology (all P < .01). Sperm dose used in AI had no effect on farrowing rate (80.7 vs 81.5%), but the lower AI dose resulted in a reduction (P < .05) in total numbers born (10.8 vs 10.0). For all three semen dilutions, estimated potential embryo production rate accounted for up to 70% of the variation in litter size obtained with 3 x 10(9) sperm per AI dose, and the number of sperm attached per oocyte was a major factor accounting for variation in litter size obtained with 2 x 10(9) sperm per AI dose. These IVF variables may, therefore, be effective indicators of boar sperm quality for use in AI. With 2 x 10(9) sperm per AI dose, the percentage of sperm with normal morphology also explained a large part of the variance in litter size born (R2 = .59), indicating that morphological characteristics are a useful measure of semen quality.

No abstract

A total of 913 boned pork loins were selected in a commercial cutting operation on the basis of color measured by a Colormet surface colorimeter. Color (L, a, b values) at three locations, free water, and ultimate pH were measured on each loin. In addition, the genotype with respect to malignant hyperthermia was determined by a restriction endonuclease assay. Six hundred ninety-three loins were determined to be of normal (NN) genotype, 198 heterozygote (Nn), and 22 homozygote (nn). This distribution reflected the selection strategy and not the incidence in the general population. Meat was darker (P < .01) and free water was reduced (P < .01) in NN loins compared to Nn or nn loins. Ultimate pH was lower (P < .01) in Nn loins than in NN loins. An increase in the incidence of Nn or nn meat samples was observed as the paleness of the loins or their free water content increased, or as the ultimate pH of the meat decreased. Based on this study, approximately 30% of meat classified as PSE on a color basis would come from heterozygote pigs.

Seventy male dairy black and white veal calves were allotted to five treatment groups: MILK, in which animals received exclusively milk replacer; MIX, in which animals received concentrates ad lib and milk replacer during the whole period, more specifically, 750 g of milk powder d−1 starting at week 4; GRAIN, in which animals received milk replacer during the first 4 wk and concentrates during the whole period; MIX+EDTA and GRAIN+EDTA, in which animals received the same diet as their respective controls plus 15 mg of EDTA mg−1 of Fe in the concentrates of the diet starting at week 4 of the experiment. MILK–fed calves had better average daily gains (ADG) than MIX–EDTA–fed or GRAIN+EDTA–fed calves (P < 0.001). However, GRAIN+EDTA–fed calves had lower ADG than GRAIN calves (P < 0.01). The EDTA treatments were without effect (P > 0.10) on feed efficiency and EDTA did not affect N digestibility (P > 0.10) or Fe retention (P > 0.10). Treatments with EDTA lightened the color of the meat (P < 0.01), reduced myoglobin and reduced muscle Fe (P < 0.01). Diet reduced carcass fatness in the following decreasing order: MILK, MIX, GRAIN. Treatments with EDTA had no effect on carcass composition. Key words: Veal, milk-replacer, grain, meat color, chelator

A restriction endonuclease assay (REA) that reveals a C/T transition in the ryanodine receptor gene (ryr-1 locus) was proposed to test swine for malignant hyperthermia. The REA was tested in a heterologous pig population of 1,227 individuals representing Hampshire, Duroc, Landrace, and Yorkshire breeds. Of this group, 713 pigs had been classified on the basis of the halothane challenge and progeny testing into the three possible Hal genotypes (685 negatives, 24 carriers, and 4 susceptibles). The REA confirmed the four susceptibles as T/T, 17/24 carriers as C/T, and 659/685 negatives as C/C. The rest of the sample was constituted of 514 pigs that had not been selected on the basis of the halothane gene. The proportions of C/T and T/T pigs within the breeds represented were 3.2 and 1.6% for Duroc, 27.3 and 1.4% for Landrace, and 17.9 and 1.9% for Yorkshire. No T/T allelic pairs were found in the Hampshire breed, although the sample was very small. Genotypic distribution and allelic frequencies at the ryr-1, Phi, and Pgd loci were reported among the breeds.