C. J. Lupton

Medullation in mohair

Abstract Experiments reporting incidence of medullated fiber in mohair were reviewed. Genetics, nutrition, season and disease have been implicated in affecting medullation levels which are variable within fleeces. To measure medullation accurately, representative samples of the whole fleece must be measured. Subjective medullation scores are of limited value since they are not highly correlated with actual measurements of medullation. Progress towards reducing medullated fibers in mohair is possible by selection of animals older than one year of age. The environmental factors nutrition, geographical location and disease have minimal effects on medullated fiber production. Effects of season and management on medullation are not clear.

Impacts of animal science research on United States sheep production and predictions for the future

One hundred years ago, there were more than 48 million sheep in the United States. In 1910, they were valued at

Heritability of juniper consumption in goats

4/head, with 43% of income coming from the sale of sheep, lambs, and meat and 57% coming from wool. Over the years, fluctuations in this ratio have challenged the breeder and researcher alike. By 2007, sheep numbers had declined to 6.2 million, with the average sheep shearing 3.4 kg of wool (representing <10% of income), 0.2 kg more than in 1909 but 0.5 kg less than fleeces in 1955. Sheep operations have declined by more than 170,000 in the past 40 yr. A cursory examination of this information might lead one to conclude that animal science research has made little impact on sheep production in the United States. On the contrary, lamb crops in the new millennium (range = 109 to 115%) are greater than those recorded in the 1920s (85 to 89%) and dressed lamb weights increased from 18 to 32 kg from 1940 to the present. In the past century, researchers conducted thousands of investigations, with progress reported in new, existing, and crossbreed evaluations, quantitative and molecular genetics, selection, nutrition, fiber, meat, hides, milk, growth, physiology, reproduction, endocrinology, management, behavior, the environment, disease, pharmacology, toxicology, and range, pasture, and forage utilization such that a vast amount of new information was accrued. Our understanding of sheep has benefited also from research conducted on other species, and vice versa. Many factors that have contributed to the decline in the sheep industry are not influenced easily by academic research (e.g., low per capita consumption of lamb meat, predation, reluctance to adopt new technologies, cost and availability of laborers with sheep-related skills, and fewer young people pursuing careers in agriculture). The size of the US sheep industry is expected to remain stable, with possible slow growth in the foreseeable future. To remain profitable, producers will take advantage of new (or previously unused) technologies, the desire of the public for things natural, domestic niche and international fiber markets, and the ability of the sheep to control noxious weeds and thrive in suboptimal ecosystems.

Pharmacokinetic differences in exposure to camphor after intraruminal dosing in selectively bred lines of goats

Data from goats (n = 505), collected over a 4-yr period, were used to estimate the heritability of juniper consumption. Juniper consumption was determined by near-infrared spectroscopy on fecal samples (n = 1,080) collected from female Boer-cross goats grazing pastures with a variety of plants, including juniper. The animals with records were progeny of 72 sires. Individual goats had from 1 to 4 observations over a 4-yr period. Predicted juniper consumption for individual observations ranged from -5 to +62% of the diet. Data were analyzed with a mixed model that included management group as a fixed effect, BW as a covariate, and permanent environment, animal, and residual as random effects. Management group was a significant source of variation. Least squares means of juniper consumption, as a percentage of the total intake, for management groups varied from 19 to 47%. Heritability of juniper consumption was 13%. Repeatability of juniper consumption was 31%. These results suggest that progress to selection for goats that will consume greater amounts of juniper is obtainable, but is expected to be slow.

Sulfate supplementation of Angora goats: metabolic and mohair responses.

A pharmacokinetic dosing study with camphor was used to determine whether selection lines of high-juniper-consuming goats (HJC, n = 12) and low-juniper-consuming goats (LJC, n = 12) differed in their respective disposition kinetics. Postdosing plasma camphor concentrations were used to examine whether a timed single blood sample collected after intraruminal administration of camphor would be a useful screening test to aid in the identification of HJC. Yearling female Boer x Spanish goats (n = 24) received a single intraruminal dose of monoterpene cocktail (0.270 g/kg of BW) containing 4 different monoterpenes that represented their composition previously reported for Ashe juniper (Juniperus ashei). Camphor, the predominant monoterpene in Ashe juniper, was 49.6% of the mix and was the monoterpene analyzed for this study. Blood samples were taken at 15 time points from 0 to 8 h after dosing. Concentrations of camphor were measured in plasma using solid phase extraction and gas chromatography/flame-ionization detection analysis. Maximal plasma concentration of camphor was greater for LJC than HJC (P = 0.01), and area under the curve extrapolated to infinity was greater for LJC than HJC (P < 0.01). Total systemic exposure (area under the curve) to camphor was 5 times less in HJC goats. We conclude that 1) HJC goats possess internal mechanisms to reduce the bioavailability of camphor, and 2) a blood sample taken at 45 min or at 60 min after intraruminal administration of camphor may be useful for identifying HJC individual animals from within large populations of goats.