Biomedical subjects
Publications and source records attributed to A P Grifo.
Based on data from 33 sheep, bacterial concentrations per gram of rumen contents were correlated highly with total bacterial numbers (r = .99). Diets ranged from all forage to 90% concentrate. Similar data were obtained from cattle fed a corn silage diet (r = .95); however, the slope of the regression lines differed between species. Weight of rumen contents was correlated poorly with total bacterial numbers.
Based on results from eight experiments, no overall difference was found between roll tube and three- and five-tube most-probable-number (MPN) methods for estimating total numbers of ruminal bacteria. However, standard errors for the replicate means within an experiment were higher with the MPN procedures. Visual growth and pH were the criteria used for scoring the MPN tubes. Total numbers were significantly higher in MPN medium containing 40% ruminal fluid, as compared with a complete medium without ruminal fluid. By using a broth medium containing ball-milled cellulose and soluble carbohydrates as energy sources, it was possible to estimate both total and cellulolytic ruminal bacterial numbers in the same MPN series. Disappearance of cellulose and decrease in pH were used to determine growth. Values did not differ from those obtained in separate MPN assays. By using this method, diurnal changes in total and cellulolytic bacterial numbers were estimated in sheep fed forage or a concentrate-type diet.
Three experiments were conducted to evaluate the effect of exposure of the uterus to semen at least 3 wk before breeding on subsequent reproductive performance. In Exp. 1, uterine exposure to semen was performed three times. At least 3 wk elapsed between each treatment. Control gilts received saline infusion. All gilts were bred by artificial insemination using semen from the same boars used for semen treatment. At farrowing, significantly more (10.35 vs 8.39) pigs/litter were produced by semen-treated gilts than controls. However, due to a disease outbreak (porcine parvovirus) during the last two-thirds of the farrowing period, live pigs born and litter size at 2 wk were not statistically different between the two groups. Gilts that farrowed were rebred and no difference in their reproductive performance for second litters was noted. For Exp. 2 and 3, a single semen treatment was given using freeze-thaw killed semen at estrus before breeding. Within both Exp. 2 and 3, semen-treated gilts had a larger average litter size, but no significant differences were detected. When data for nondiseased animals in Exp. 1 and animals in Exp. 2 and 3 were pooled, it was found that total pigs born (P less than .01), live pigs born (P less than .01) and live litter birth weight (P less than .1) were all greater in semen-treated gilts than in controls. Thus, these results indicate that reproductive efficiency in gilts can be improved by intrauterine treatment with boar semen before insemination to elicit conception.
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A study of 10 mature crossbred, ovariectomized gilts was conducted to determine whether riboflavin secretion by porcine uteri is regulated by estrogen and progesterone. A second experiment was performed to determine whether secretion of riboflavin occurs in pregnant animals in a temporal and quantitative pattern similar to that in nonpregnant animals. In the hormonal induction experiment, it was found that animals receiving daily injections of estrogen for 5 days followed by a daily injection of a combination of estrogen and progesterone were able to secrete riboflavin in quantities comparable to those secreted by intact animals. Additionally, it was found that the secretion of riboflavin appeared to be related to onsetn of treatment with progesterone in that riboflavin secretion increased in a time-related pattern after the beginning of progesterone treatment. In a second experiment, pregnant animals secreted riboflavin in their uterine secretions in quantities and in a time pattern similar to those found in nonpregnant animals. Nonpregnant gilts in the 8th day of an estrous cycle were used for comparison to the pregnant animals in this experiment, and the quantity of riboflavin uterine secretions in the nonpregnant animals was similar to that found on day 8 in the pregnant animals. Taken together, these two experiments indicate that riboflavin is secreted under hormonal regulation by the uterus in both pregnant and nonpregnant pigs at a precisely controlled time in the progestational phase.
Porcine allantoic and amniotic fluids from early, mid and late pregnancy were analyzed for protein constituents and ability to suppress phytohemagglutinin (PHA)-induced lymphocyte transformation. All fetal fluids contained alpha-fetoprotein as evaluated by polyacrylamide gel electrophoresis (PAGE), with the highest concentrations appearing in mid-pregnancy amniotic fluids. In addition, allantoic fluids from mid-pregnancy contained proteins assumed to be secreted by the uterus. Both allantoic and amniotic fluids from mid-pregnancy were suppressive to PHA-induced lymphocyte transformation (P<.01). Thus it was concluded that substances, potentially able to suppress the immune response locally, exist within porcine fetal fluids, but it was not determined whether this material is of solely fetal or maternal origin, or a combination.
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