PubMed Health⌕ Search

Biomedical subjects

R L Fernando

Publications and source records attributed to R L Fernando.

42 records · Page 3Linked to original sources
PubMed1986

Correlations between parities for lactation traits in United States dairy goats.

Correlations between parities for milk yield, fat yield, and days in milk were calculated across and within does for five breeds of United States dairy goats; Alpine, LaMancha, Saanen, and Toggenburg, using lactation records to January 1981. Records were initiated during 1966 through 1979 and had between 125 and 305 d in milk. Parities were first through fourth, and fifth or greater. Overall phenotypic correlations between the three lactation traits averaged across breed were .95 between milk and fat yield and about .60 between milk or fat yield and days in milk. Within-herd phenotypic partial correlations between parities 1 and 2 (the two parities with most data) averaged .47 for milk yield, .42 for fat yield, and .07 for days in milk. Components of variance due to herd averaged about 34% for milk yield and for fat yield and 23% for days in milk. Components of variance due to doe/herd averaged 28% for milk yield, 25% for fat yield, and 17% for days in milk. Repeatabilities averaged .42 for milk yield, .38 for fat yield, and .22 for days in milk.

Animals↗
PubMed1984

Effects of intake of a mixed dairy steers on digestion events.

Ruminally cannulated steers were in a 4 X 4 Latin square to determine the effect of amount of feed ingested on fiber digestion and other digestion events. Alfalfa haylage, corn silage, and a corn-soybean meal mix were incorporated in a ratio 45:20:35 (dry matter) and fed at either 100, 85, 70, or 55% of ad libitum intake. Acid-insoluble ash, lanthanum, and chromium-ethylenediaminetetraacetic acid were digestion, particulate, and liquid markers. Apparent digestibility of dry matter, neutral detergent fiber, and cell solubles decreased linearly as feed intake increased. The fiber fraction digested was a larger percentage of the dry matter digested at low than at high intakes of feed. A more rapid rate of cellulose disappearance and a slow rate of passage of particulate matter through the rumen and total digestive tract with decreasing feed intake were key factors responsible for bringing about changes of digestion coefficients. A consistently lower rumen pH of steers at high intakes of feed was thought to account for the slower rate of ruminal fiber disappearance. The lower tract accounted for 11 to 17% of dry matter disappearance, and tended to play a greater role during periods of high feed intake. Rumen and fecal sampling techniques provided similar ruminal rates of solids passage.

Ammonia↗
PubMed1977

The Laurence-Moon-Biedl syndrome in a Singhalese family.

The first published occurrence of the Laurence-Moon-Biedl Syndrome in a Singhalese family is reported. Three members of a family of six with first cousin non-affected parents are described along with studies to indicate that the hypogonadism in this family can be ascribed to hypogonadotrophism. The high incidence of congenital heart disease and genito-urinary abnormalities noted by other is confirmed.

Adolescent↗
PubMedDate not supplied

Sampling genotypes in large pedigrees with loops.

Markov chain Monte Carlo (MCMC) methods have been proposed to overcome computational problems in linkage and segregation analyses. This approach involves sampling genotypes at the marker and trait loci. Scalar-Gibbs is easy to implement, and it is widely used in genetics. However, the Markov chain that corresponds to scalar-Gibbs may not be irreducible when the marker locus has more than two alleles, and even when the chain is irreducible, mixing has been observed to be slow. These problems do not arise if the genotypes are sampled jointly from the entire pedigree. This paper proposes a method to jointly sample genotypes. The method combines the Elston-Stewart algorithm and iterative peeling, and is called the ESIP sampler. For a hypothetical pedigree, genotype probabilities are estimated from samples obtained using ESIP and also scalar-Gibbs. Approximate probabilities were also obtained by iterative peeling. Comparisons of these with exact genotypic probabilities obtained by the Elston-Stewart algorithm showed that ESIP and iterative peeling yielded genotypic probabilities that were very close to the exact values. Nevertheless, estimated probabilities from scalar-Gibbs with a chain of length 235 000, including a burn-in of 200 000 steps, were less accurate than probabilities estimated using ESIP with a chain of length 10 000, with a burn-in of 5 000 steps. The effective chain size (ECS) was estimated from the last 25 000 elements of the chain of length 125 000. For one of the ESIP samplers, the ECS ranged from 21 579 to 22 741, while for the scalar-Gibbs sampler, the ECS ranged from 64 to 671. Genotype probabilities were also estimated for a large real pedigree consisting of 3 223 individuals. For this pedigree, it is not feasible to obtain exact genotype probabilities by the Elston-Stewart algorithm. ESIP and iterative peeling yielded very similar results. However, results from scalar-Gibbs were less accurate.

Algorithms↗