Biomedical subjects

T R Famula

Publications and source records attributed to T R Famula.

At least 37 records · Page 2Linked to original sources

PubMed1997

Negative feedback potency of estradiol is increased in orchidectomized sheep during chronic nutrient restriction.

The effect of nutrient restriction on serum concentrations of the gonadotropins, on the pattern of LH secretion, and on sensitivity to estradiol (E2) was assessed in orchidectomized sheep (wethers). Thirty-six wethers (initial weight = 42.3 +/- 0.6 kg) were fed to gain, maintain, or lose body weight (feeding groups G, M, and L, respectively; n = 12 wethers/group). After 7 wk of controlled feeding, G, M, and L wethers weighed 57.0 +/- 1.7, 42.5 +/- 0.6, and 36.6 +/- 0.8 kg, respectively. At the end of controlled feeding, serum concentrations of LH and FSH in M and L wethers were significantly higher than levels in G wethers. During Days 51-54 of controlled feeding, six animals from each feeding group received E2 or vehicle as a continuous infusion. The pattern of LH secretion was assessed 48 h after initiation of infusion. Although E2 infusion did not affect (p > 0.05) LH pulse frequency in G and M wethers, pulse frequency was reduced (p < 0.05) in L wethers receiving E2. These data indicate that serum concentrations of gonadotropins are increased in wethers fed to maintain or lose body weight. In addition, the negative feedback potency of E2 is enhanced during prolonged weight loss.

Animal Nutritional Physiological Phenomena↗

PubMed1997

Heritability of epileptic seizures in the Belgian tervueren.

Survey data were collected on the incidence of epileptic seizures in 997 Belgian tervuerens. The heritability of this disorder was estimated as 0.77 (with a 95 per cent confidence interval spanning from 0.65 to 0.88) using a Bayesian analysis in an ordered categorical threshold model. Single locus models do not appear adequate as an explanation for this inherited seizure disorder. The high heritability estimate suggests that breeders can wage a successful battle against this disorder by breeding unaffected individuals, particularly those from families with no history of seizures.

Age Factors↗

PubMed1997

Effects of milk protein genotypes on the variation for milk production traits of Holstein and Jersey cows in California.

The objectives of this study were to form appropriate composite kappa-beta-alpha(s1)-CN genotypes in order to assess which genotypes were favorably associated with first lactation milk production, fat and protein percentages, and fat and protein production for data of 916 Holstein and 116 Jersey cows. Multiple-trait animal models were used with assumed fixed effects for herd, year and season of calving, age at calving, days open, composite kappa-beta-alpha(s1)-CN genotypes, and beta-LG genotypes. The differences between the beta-LG genotypes for production traits were not statistically significant for either breed. The proportion of phenotypic variance that was due to the composite kappa-beta-alpha(s1)-Cn genotypes was 5% for milk production, 4% for protein production, and 3% for fat percentage. The kappa-beta-alpha(s1)-CN genotype ABA1A2BB was superior to the comparable AAA1A2BB and ABA1A1BB genotypes by 252 and 338 kg for first lactation milk yield, respectively, and 8.7 and 11.5 kg for protein yield, respectively. Thus, neither the beta-CN A2 allele nor the kappa-CN B allele alone had a positive effect on milk and protein production, but the joint effect was strongly positive. These results may be explained by epistatic effects between the kappa-CN and beta-CN loci and possibly by closely linked quantitative trait loci with favorable alleles on the kappa-beta-alpha(s1)-CN BA2B haplotype.

Animals↗

PubMed1996

A threshold model analysis of deafness in Dalmatians.

To elucidate the inheritance of deafness in Dalmatian dogs, 825 dogs in 111 litters were evaluated for abnormalities in hearing through the brainstem auditory evoked response (BAER). Recorded along with their quality of hearing (normal, unilaterally deaf, or bilaterally deaf) were the sex, coat color, eye color and the presence or absence of a color patch. The analysis considered deafness an ordered categorical trait in a threshold model. The underlying, unobservable continuous variate of the threshold model was assumed to be a linear function of sex of dog, coat color (black or liver and white), color patch (presence or absence), eye color, the deafness phenotype of the parents and a random family effect. Twenty-six percent of dogs were deaf in at least one ear. Eye color, color patch, sex and the hearing status of the parents were all significant contributions to deafness. The heritability of deafness, on the continuous unobservable scale, was 0.21. This value was computed after correction for eye color, color patch, parental hearing status and sex, implying that significant genetic variation exists beyond the contribution of several single loci.

Animals↗

PubMed1994

Boar sperm plasma membrane protein profile: Correlation with the zona-free hamster ova bioassay.

This study was designed to compare differences among porcine sperm plasma membrane proteins with the ability of spermatozoa to interact with zona-free hamster ova. Sperm plasma membrane vesicles were recovered from 24 ejaculates from 10 fertile boars, and from cauda epididymal spermatozoa from 3 fertile and 1 very subfertile boar. Solubilized sperm plasma membrane proteins were run on 1D SDS-PAGE gels, transferred to western blots, stained, and analyzed for quantity of protein per band by scanning laser densitometry. Variation in the quantities of individual sperm plasma membrane proteins in the 20 identified bands were statistically compared with the ability of spermatozoa from the same ejaculate to penetrate zona-free hamster ova. The percentages of plasma membrane protein present in 3 bands (90, 84 and 60 kD) were positively correlated with the ability of spermatozoa from the same ejaculate to fuse with zona-free hamster ova (P = 0.002, 0.01, 0.04; R = 0.53, 0.40, 0.38, respectively). The quantities of protein in 2 other bands (69 and 35 kD) were significantly but negatively correlated with the results of the zona-free hamster ova bioassay (P = 0.02, 0.01; R = -0.42, -0.37, respectively). The sperm plasma membrane profiles were quantitatively similar between the ejaculated samples and the fertile epididymal samples. Six epididymal sperm plasma membrane proteins were present in statistically different quantities in the subfertile boar sample and the 3 fertile controls. The 90 kD band positively correlated with the hamster ova bioassay in the ejaculated samples was not detected in the subfertile epididymal sperm plasma membrane sample. These results suggest that protein(s) in one or more of the 3 positively correlated ejaculated sperm plasma membrane protein bands may be involved in sperm-oocyte interaction.

Journal Article↗

PubMed1994

Estimation of genotype effects for milk proteins with animal and sire transmitting ability models.

The objective of this work was to estimate the contribution of milk protein genotype to production traits of Holstein cattle. Two approaches were employed. The first was based on an animal model analysis of milk records in which cows were genotyped for milk protein variants. The second approach was the analysis of PTA of sires in which the sires were genotyped for their milk protein variants. Results of the animal model analysis agreed qualitatively with previously published analyses of cow records, indicating only a minor contribution of milk protein genotype to production traits. Qualitative similarity was also found between the analysis of sire transmitting abilities and the animal model. Algebraic results suggested, however, that an indirect analysis of published sire transmitting abilities does not provide unbiased estimates of differences in milk protein genotypes. Although analysis of PTA is simple, only a direct analysis of genotyped cows with an animal model provides unbiased estimates of genotype differences.

Animals↗

PubMed1993

The contribution of progeny of uncertain paternity to the accuracy of sire evaluation.

Recent advances in statistical methodology now permit the genetic evaluation of animals with uncertain pedigrees. Although widescale practice of these techniques is not likely, implementation will never occur until we characterize the effect of uncertain pedigrees on the accuracy of animal evaluation. This work develops the framework for such a characterization, illustrating the contribution of uncertainly identified records to accuracy of evaluation through a hypothetical example. The effect of including records of uncertain paternity is greatest for sires with few certainly identified progeny. Thus, young sires stand to benefit the most from the inclusion of progeny records with uncertain paternity. In general, as the level of uncertainty in the data is replaced by the inclusion of progeny with certain paternity, the accuracy of evaluation increases. However, situations do arise in which the accuracy unexpectedly declines with the addition of progeny records with certain paternity.

Animals↗

PubMed1992

Simple and rapid inversion of additive relationship matrices incorporating parental uncertainty.

Animals bred in pastoral systems are often part of multiple-sire groups, introducing uncertainty into pedigrees. Genetic evaluation of sires and dams in such instances is complicated by the uncertainty of parenthood. This article defines a simple and rapid algorithm to compute the inverse of a numerator relationship matrix under uncertain parenthood. The algorithm can accommodate inbreeding and uncertainty of parenthood on both paternal and maternal sides of the pedigree.

Algorithms↗

PubMed1991

Inheritance of litter size and its components in crosses between the D'man and Sardi breeds of sheep.

Data on ovulation rate, litter size and embryo survival of 364 Sardi (S), D'man (D), S x DS, DS x S, S x D, D X S (F1), F2, D x DS and DS x D ewes mated for first and second lambing to F1 rams were analyzed. Breed group, birth group and season had significant effects on ovulation rate and litter size but not on embryo survival. D'man ewes had the highest ovulation rate (2.79) and litter size (2.00), with an essentially linear increase in each of these variables with percentage of D'man inheritance in the ewe (b = .017 +/- .001 CL and .009 +/- .001 lambs born). Embryo survival was influenced only by the number of ova shed. D'man direct genetic effects were higher (P less than .01) than those of Sardi for ovulation rate (+1.78) and litter size (+1.08) but did not differ for embryo survival (-.07). Maternal effects differed little for any of the three traits. Individual heterosis estimates were negative and significant for ovulation rate but not significant for litter size and embryo survival. Maternal heterosis and epistatic recombination effects were small and not significant for any trait.

Animals↗

PubMed1991

Ovulation rate and pre- and postimplantation survival in mice with a major gene for rapid postweaning gain.

Differences in ovulation rate, embryo survival, litter size, and fertility are presented for four lines of mice that have been selected for growth or are homozygous for a recessive gene (hg) imparting rapid postweaning gain. Two of the lines were hg/hg, one in a growth-neutral and one in a growth-selected background. The remaining two were Hg/Hg (the corresponding normal, dominant allele with no effect on postweaning gain) in the same two backgrounds. Average ovulation rates ranged from 10.9 to 17.1 eggs shed, and litter sizes ranged from 8.6 to 14.0. In the growth-selected background, the hg allele reduced the number of ovulations, implantation, and litter size by nearly three compared with the Hg/Hg controls. The impact of the hg allele in the growth-neutral background was not significant. When males of a different line selected for high litter size were mated to females of the four stocks, more than two additional eggs, implants, and pups were recorded, compared with results of mating to males of the same line as the female.

Alleles↗

PubMed1991

The use of integer programming in dairy sire selection.

A computerized sire selection integer program, IPSIRE, was developed to test the optimality of solutions obtained by using MAXBULL, a popular computerized sire selection aid. The IPSIRE program uses an optimization software package and a compatible spreadsheet; MAXBULL uses linear programming techniques. The computer programs were compared using large and small data sets. Multiple combinations were run, varying the levels requested for PD fat percentage, PD type, and price paid per unit of semen. All other constraints were held constant. The objective function for all combinations maximized PD milk. The IPSIRE program exceeded MAXBULL by an average of $2.5 for PD dollars and 7.3 kg (16.1 lb) for PD milk using the small bull data base. Sire averages for traits PD type, PD fat percentage, and price paid were not different between the two programs. Similar trends were seen using the large bull data base. The IPSIRE program exceeded MAXBULL by an average of $1.2 for PD dollars and 4.1 kg (9.0 lb) for PD milk, whereas sire averages for PD fat percentage, PD type, and price paid were not different between programs. The goal for PD type had the least influence of the three goals on sire averages for PD milk. The goal for price paid had the greatest impact on realized PD milk; higher goals for price paid produced solutions with higher values for realized PD milk. The IPSIRE program required longer computational times for finding solutions that maximized PD milk than MAXBULL.

Animals↗

PubMed1990

Feedlot performance of beef heifers implanted with Synovex-H: effect of melengestrol acetate, ovariectomy or active immunization against GnRH.

The effects on anabolic steroid implantation on feedlot performance and carcass composition and quality were examined in control (CNTRL), ovariectomized (OVX) or melengestrol acetate-fed (MGA) beef heifers or heifers actively immunized against GnRH (Anti-GnRH). Heifers (n = 112) were assigned randomly to a 2 x 4 factorial experiment. The two classes were made up of heifers not implanted and those implanted with Synovex-H. The four treatments were 1) CNTRL, 2) MGA, 3) OVX and 4) Anti-GnRH. Heifers were housed in individual pens and fed a high-energy diet for the 4-mo study. Synovex-H increased final live weight (P less than .005), carcass weight (P less than .005), ADG (P less than .0001) and feed efficiency (P less than .005) but did not alter carcass quality and yield grade (P greater than .05). Synovex-H increased deposition of protein (P less than .0001) and reduced deposition of fat (P less than .0001). Oral administration of MGA had no significant effect on feedlot performance or carcass quality. For heifers not implanted, active immunization against GnRH, but not ovariectomy, depressed ADG (P less than .05) and increased fat deposition (P less than .05) while reducing protein deposition (P less than .05). These effects of active immunization were reversed by concurrent administration of Synovex-H. Feedlot performance and carcass composition of heifers were improved by administration of anabolic steroids. When heifers were housed singly, neither ovariectomy, active immunization against GnRH nor oral administration of MGA improved feedlot performance of heifers implanted with Synovex-H.

Animals↗

PubMed1988

Organ and skeletal growth in mice with a major gene for rapid postweaning growth.

Growth of liver, heart, kidney and femur in mice with a major gene for rapid postweaning growth (hg/hg, line Ch) was compared to that of their normal controls (Hg/-, line CH). Male mice of both lines were sacrificed at 7 day intervals from 21 to 56 days of age. By day 56 mice of line Ch weighed 40.1 g and individuals of line CH weighed 30.2 g. At sacrifice, individuals were weighed, the naso-anal length and tail length measured and the liver, heart and kidney were removed and weighed. The left femur was also removed and its length measured. Significant differences between lines were detected for all traits observed when examined on an uncorrected basis. This significance disappeared when organ weights were adjusted by body weight at sacrifice through covariance analysis. Similarly, there was no significant in femur length across lines when bone lengths were adjusted for naso-anal length. Only differences in tail length remained significant after adjustment for body length. These results suggest that the impact of the hg allele is of a fundamental and general nature, with little impact on specific tissues or functions of growth.

Animals↗

PubMed1987

Energetic efficiency of protein and fat deposition in mice with a major gene for rapid postweaning gain.

Previous research demonstrated the existence of a major gene (hg), expressed as a homozygous recessive, that increases postweaning growth 60% in C57B1/6 mice (line Ch) compared to the same genetic stock without the major gene (line CH). Effects of the hg gene on the partial energetic efficiencies of protein and fat deposition in mice between 21 and 42 d of age were examined by using comparative slaughter data and multiple regression techniques. Efficiency estimates for fat deposition were biologically impossible and unstable, probably as a result of high correlations between the independent variables (multicollinearity). Use of biased regression techniques gave rise to biologically possible estimates for efficiencies of fat and protein gain. However, biased regression procedures introduced subjectivity in an otherwise objective analysis. Since these regression techniques produce biologically possible estimates, the physiological implications of the results are discussed in relation to protein and fat turnover. Although the usefulness of these statistical methods for predictive purposes is not questioned, it is concluded that they do little toward advancing our understanding of energy metabolism. Rather, we suggest that mechanistic models be used wherein specific biological processes are presented separately and effects of energy intake on these processes accommodated explicitly.

Animals↗

PubMed1987

Dietary fat and nitrogen composition of milk from lactating cows.

Effects of dietary fat on milk composition, particularly milk N, were evaluated in lactating dairy cows at two stages of lactation. Complete mixed diets containing 0, 3.5, or 7% of the diet DM as animal fat were fed to 12 cows in a 3 X 3 Latin square. Cows were divided into two status categories based on stage of lactation resulting in two squares of early and two of late lactation cows. Percentages of fat, solids, lactose, and protein were decreased and ash increased in the milk of cows fed the 7% fat diet. Percent of casein N was elevated while nonprotein N was depressed by fat fed in diet. Percentage of solids and protein was higher and lactose lower for cows in late lactation than for those in early lactation. Dietary fat reduced the proportion of short-chain fatty acids in milk fat and increased C18:0 and C18:1 fatty acids. Digestibility of DM, energy, and fiber was not significantly affected by dietary fat, but estimates decreased with increased dietary fat. Cows in late lactation had a higher digestibility of dietary fractions than early lactation cows even though intakes of DM were similar.

Animals↗

PubMed1986

Maintenance energy requirement and net energetic efficiency in mice with a major gene for rapid postweaning gain.

Previous research in this laboratory demonstrated the existence of a major gene (hg), expressed as a homozygous recessive, which increases postweaning growth by 60% in C57Bl/6 mice (line Ch) compared to the same genetic stock without the major gene (line CH). The effect of the hg gene on the maintenance energy requirement and net energetic efficiency of mice between 21 and 42 d of age was examined in a comparative slaughter experiment. Regressions of changes in body energy per kilogram0.75 on metabolizable energy intake per kilogram0.75 indicated that the maintenance energy requirements averaged 164 kcal/(kg0.75 X d) and 155 kcal/(kg0.75 X d) for lines CH and Ch, respectively. Net efficiency of energy utilization was 38.5 and 49.5% for lines CH and Ch, respectively. Ad libitum-fed mice of line Ch gained 46% more total body energy per unit of metabolic body weight (kilogram0.75) than ad libitum-fed mice from line CH while their energy intake per kilogram0.75 was equal. It was estimated that the decreased maintenance energy requirement and increased net energetic efficiency accounted for approximately 25 and 75%, respectively, of the increased energy gain of ad libitum-fed mice of line Ch as compared to CH. The increased energy gain of line Ch was largely (78%) due to an increase fat energy deposition. Regressions of fat energy gain per kilogram0.75 on metabolizable energy intake per kilogram0.75 indicated that the increased fat energy gain was due to an increased efficiency of fat deposition and/or an increased proportion of metabolizable energy available for gain used for fat gain.

Animals↗

PubMed1986

Efficiency of growth in mice with a major gene for rapid postweaning gain.

Previous research in this laboratory demonstrated the existence of a major gene (hg), inherited as a homozygous recessive, which increases postweaning growth by 40 to 50% in C57Bl/6 mice (Ch) compared to the same genetic stock without the major gene (CH). Although its effect has not been previously evaluated, this single recessive allele is also in a line of mice selected for rapid postweaning gain for over 70 generations. Gh represents that line of mice with the major gene for growth (hg) in the growth-selected background and GH the growth-selected background without the major gene. Total body weight, daily weight gain, feed consumption and gain/feed, measured daily from 21 to 42 d of age, were all significantly greater (p less than .01) in the two lines with the hg/hg genotype (Ch and Gh) compared with their respective control lines (CH and GH). Differences in body composition at 42 d of age between CH compared with Ch and GH compared with Gh were accounted for by difference in body weight. Gross and net energetic efficiency, calculated assuming a similar maintenance energy requirement, were improved (P less than .01) in Ch and Gh compared to CH and GH, respectively. The results demonstrated that hg influences growth in growth-neutral and growth-selected backgrounds. The gene also alters energy metabolism by increasing energetic efficiency of growth and(or) decreasing maintenance energy requirement.

Age Factors↗

PubMed1986

Fertility, embryo survival and litter size in lines of Targhee sheep selected for weaning weight or litter size.

Conception rate, prenatal survival and litter size were recorded for 444 ewes of two age groups from five lines of grade Targhee sheep: two unselected control lines, HC1 and DC(C); two lines selected for 20 yr for increased 120-d weight, HW and DH(W); and a line selected for 18 yr for increased multiple births, T. Line T was equal or superior to the control lines in conception rate, prenatal survival and litter size in both age groups, although most of the differences were not significant. The W selected lines were inferior to the C and T lines in fertility and tended to be lower in prenatal survival, among mature ewes, resulting in a significantly lower number of lambs born per corpus luteum in the W lines than in the other two groups. Among yearlings, C ewes were non-significantly lower in fertility than T and W ewes, while W ewes were significantly lower than C and T ewes in prenatal survival. The T line ewes had higher overall reproductive performance than either of the other two groups. Ewes with two ovulations had a significantly higher conception rate than ewes with single ovulations. Gestation period was exceptionally uniform with a coefficient of variation of 1.3% and little difference due either to line or litter size. It was concluded that selection for multiple births improved overall reproductive performance, whereas selection for increased growth rate had an adverse effect on several components of reproduction, leading to a net decline in fitness.

Animals↗