Estrus, ovulation, conception and embryo survival in confinement-managed gilts of three weight groups.

Puberty, cycling, ovulation, conception and embryo survival were determined for gilts managed by a specific regimen in confinement. At weights of 70 to 80, 91 to 100 and 109 to 116 kg (groups A, B, C, respectively) gilts were (1) moved from rearing pens to pens in a separate broodstock building, (2) housed in groups of eight to 10 with unfamiliar penmates and (3) exposed to boar presence in an adjoining pen. Groups A and B were mated at third estrus; group C was mated at first estrus. For the three groups 76, 79 and 79%, respectively, of allotted gilts mated; of these 21, 13 and 11%, respectively, showed estrus again and were remated. Ten, 10 and 11%, respectively, were not pregnant when slaughtered at 25 to 28 d of postmating. Average days on experiment to first estrus were 14, 15 and 16 for groups A, B and C; mean interval between estrous periods was 21 d. Ovulations (13.3, 12.9 and 12.6) and live embryos (11.6, 11.1 and 10.7, respectively) did not differ significantly among groups. None of the reproduction traits were significantly associated with differences in mean age or weight among the three groups at breeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Electrical Stimulation on Meat Microflora: Observations on Agar Media, in Suspensions and on Beef Carcasses.

Electrical stimulation of beef carcasses did not cause a significant reduction in surface microbial population at three different sampling positions immediately following slaughter. However, significant microbial reduction (P<0.05) was found at position 2 (muscle above aitch bone) but not at position 1 (inside of neck) or position 3 (fat on outside of round) after 72 h of chilling storage. Nine bacterial species from eight different genera commonly associated with meat were inoculated on three different agar media which varied in electrical conductivity. Electrical stimulation of these media caused a reduction in numbers of microorganisms under various voltage and time treatments. Spore-forming bacteria were the most resistant to the electrical treatments. Among the non-spore formers, gram-negative bacteria were more resistant to electrical treatment than gram-positive bacteria. Also, microorganisms inoculated on the lowest resistance medium A revealed greater reduction in numbers than that of the other media with higher resistance. A five log cycle reduction in Escherichia coli , Pseudomonas putrefaciens and Pseudomonas fragi was found in 0.85% saline solution and phosphate buffered saline solution after a 30-V, 5-min treatment, but little change in count was detected in 0 . 1% aqueous peptone or 2.5 M sucrose solution.

The effect of pressurisation of pre-rigor muscle on post-rigor meat characteristics.

Pressurisation of pre-rigor muscles produced very firm meat in muscles which had contracted to as little as 48% of their on-carcass length. Immediate post-treatment pH was 5·81, significantly lower than the controls; however, there was no significant difference at 24 h. Water holding capacity of the treated samples was significantly lower and weep significantly higher than the controls. However, cooking losses for the treated samples were lower, resulting in an over-all loss which was not different between control and treated samples. Warner-Bratzler shear tests and taste panel evaluations indicate a highly significant improvement in tenderness. Scanning electron micrographs show an extensive disruption of the sarcolemma.