D. F. Waldron

Fatty acid composition of goat diets vs intramuscular fat

Twenty Boer x Spanish goats, at the age range of 90-118 days, were assigned to two dietary treatments, with 10 animals fed a grain ration (G) and the other 10 grazed in rangeland. The grain ration contained sorghum grain (67.5%), cottonseed hulls, dehydrated alfalfa meal, cottonseed meal, soybean meal, molasses, and mineral and vitamin supplements. Animals were slaughtered at the age range of 206-234 days. Intramuscular fat (IF) and the diet specimens - representative samples of G and the parts of range plants (RPs) that goats were expected to have consumed - were analyzed for fatty acid composition. The percentage of 16:0 was higher in RPs than in G, but not different between IF from range goats and that from grain-fed goats. Total unsaturated fatty acid (UFA) percentage was higher in G than in RPs. The major UFAs were 18:2 and 18:3 in RPs, and 18:1 and 18:2 in G. In IF, 18:1 constituted more than two-thirds of UFAs, regardless of diet type.

Maternal effects for growth traits in beef cattle

Abstract Estimates of direct and maternal heritabilities, the genetic correlation between direct and maternal additive effects, and the permanent environmental variance as a percentage of the phenotypic variance (c2) were reported for weights of beef cattle at birth, weaning, yearling and 18 months. The data consisted of one Hereford and two Angus weight selection herds, analysed separately, recorded from 1969 to 1987 with a grand total of 7291 records. A univariate animal model was used. Direct and maternal heritabilities averaged 0.30 and 0.07 respectively for birth weight, 0.14 and 0.13 for weaning weight, 0.29 and 0.04 for yearling weight, and 0.32 and 0.04 for 18-month weight, whilst c2 terms averaged 0.05, 0.15, 0.03 and 0.01 respectively. Genetic correlations between direct and maternal genetic effects in the Angus data averaged 0.20, 0.03, 0.09 and 0.27, respectively. Genetic correlations in the Hereford data were 0.37, −0.35, 0.97 and 0.95, respectively. Animal models which ignored maternal effects tended to overestimate direct heritability.

Genetic and phenotypic parameter estimates for selection to improve lamb carcass traits

Abstract The variance components needed to calculate genetic and phenotypic parameters for selection to improve carcass composition in white-faced sheep were estimated from a sire model using REML on data from 1602 Romney and Romneycross lambs. The sires were either Romney (n = 60), Border Leicester (n = 18), Poll Dorset (n = 14), or Coopworth (n = 10) with approximately 16 progeny per sire and all dams were Romney. Lambs had an average liveweight of 31.0 kg at an average age of 205 days. Carcasses were dissected into lean, subcutaneous fat, intermuscular fat, bone, and waste. The multivariate mixed linear model included birth date of the lamb as a linear covariate, year-rearing group, breed of sire, sex of lamb, birth rank, and slaughter group as fixed effects, and sire as a random effect. Traits were categorised as either lean, fat, or skeletal dimension indicators. Heritability estimates for lean indicator traits obtained by dissection averaged 0.36. The lean indicator trait with the highest heritabili...

Severe persistent orf in young goats

Orf (contagious ecthyma) is a viral disease of small and wild ruminants, humans, and less frequently other species. In sheep and goats, the disease is characterized by the formation of vesiculo-proliferative lesions in the skin of lips and nostril. Here, a form of generalized orf in 16 goat kids from 2 different locations in west Texas is described. The disease was characterized by multifocal, severe, proliferative dermatitis that persisted from about 2 months of age until the goat kids were euthanized 3 months later. All affected goats were Boer or Boer crosses under 1 year of age. The mean immunoglobulin concentration in sera of affected goats was elevated compared with healthy control goats. Severe to moderate lymphadenomegaly of the nodes draining the areas of the skin affected with orf lesions was present in all 16 goat kids. Suppurative arthritis, chronic fibrinous pneumonia, and premature thymic involution were found in 3, 5, and 7 of the goat kids, respectively. The skin lesions of 3 goat kids were infested with larvae of the opportunistic black garbage fly (Ophira sp.). The orf virus was identified in skin lesions by isolation in Marbin—Darby ovine kidney cells, electron microscopy, and amplification of viral DNA by polymerase chain reaction. The orf virus was not detected in peripheral blood or lymph node mononuclear cells of any of the goats. Cross-neutralization experiments showed that an ovine orf virus antiserum raised in sheep was more effective in neutralizing a sheep orf virus isolate than a caprine orf virus isolate. The clinical and epidemiological characteristics of these orf cases may be the result of susceptibility factors within some individuals of the Boer breed of goats.

Extended scrapie incubation time in goats singly heterozygous for PRNP S146 or K222

Scrapie is the transmissible spongiform encephalopathy (TSE) of sheep and goats, and scrapie eradication in sheep is based in part on strong genetic resistance to classical scrapie. Goats may serve as a scrapie reservoir, and to date there has been no experimental inoculation confirming strong genetic resistance in goats. Two prion protein variants (amino acid substitutions S146 and K222) in goats have been significantly underrepresented in scrapie cases though present in scrapie-exposed flocks, and have demonstrated low cell-free protein conversion efficiency to the disease form (PrP(D)). To test degree of genetic resistance conferred in live animals with consistent exposure, we performed the first oral scrapie challenge of goats singly heterozygous for either PRNP S146 or K222. All N146-Q222 homozygotes became clinically scrapie positive by an average of 24months, but all S146 and K222 heterozygotes remain scrapie negative by both rectal biopsy and clinical signs at significantly longer incubation times (P<0.0001 for both comparisons). Recent reports indicate small numbers of S146 and K222 heterozygous goats have become naturally infected with scrapie, suggesting these alleles do not confer complete resistance in the heterozygous state but rather extend incubation. The oral challenge results presented here confirm extended incubation observed in a recent intracerebral challenge of K222 heterozygotes, and to our knowledge provide the first demonstration of extended incubation in S146 heterozygotes. These results suggest longer relevant trace-back histories in scrapie-eradication programs for animals bearing these alleles and strengthen the case for additional challenge experiments in both homozygotes to assess potential scrapie resistance.

Effects of Supplementation on Juniper Intake by Goats

Abstract The potential for winter supplementation to increase juniper intake by goats on rangelands in the Edwards Plateau region of Texas was assessed in two experiments. The first experiment evaluated the effect on juniper intake of either no supplementation (negative control) or supplementation with corn, alfalfa, or cottonseed meal fed at an isonitrogenous protein level of 1.5 g · kg body weight−1 for 12 days. Redberry juniper (Juniperus pinchotii Sudw.) consumption by individually penned Spanish, Boer × Spanish, Spanish × Angora, and Angora goats was measured on days 11 and 12. Each goat received each supplement in a complete 4 × 4 Latin square design. Juniper intake increased for goats supplemented with alfalfa and cottonseed meal (P = 0.001), but not for those supplemented with corn (P = 0.944). Boer × Spanish goats did not differ in levels of consumption (P = 0.085) from the other breeds. A second study investigated the effect of either no supplementation or soybean meal supplementation on juniper consumption by free grazing Angora and Boer × Spanish goats. Forty goats were assigned to four pasture groups by breed and previous juniper intake, and randomly allocated to either the treatment (supplementation) or control (no supplementation) regime in a complete block design. After 4 days of grazing and supplementation, fecal samples were collected to estimate percent of juniper in the diet using near-infrared spectroscopy. Goats were then rotated to another pasture. Juniper intake was highest for goats supplemented with soybean meal (P = 0.034). Breed of goat did not affect intake (P = 0.240). Goats previously categorized as high juniper consumers based upon prior measurements of juniper intake ate more juniper (P = 0.003) than those classified as low consumers. This research indicates that the effectiveness of goats for biological control of juniper can be improved with a high protein, low starch supplement.

Consumer sensory evaluation of plain and seasoned goat meat and beef products.

Plain meat loaves and chili were prepared with ground goat meat or beef containing 15% fat. A consumer sensory panel first rated meat loaf samples for acceptability on a 9-point hedonic scale. Then, meat loaf samples, followed by chili samples, were each evaluated in triangle test for differentiation between goat meat and beef. Acceptability scores were similar for plain goat meat and beef loaves when the goat meat product was served before the beef product, but were lower for the goat meat with reverse serving order. In triangle tests, goat meat was differentiated from beef, whether plain or seasoned products.

Prion gene (PRNP) haplotype variation in United States goat breeds (Open Access publication)

Scrapie eradication efforts cost 18 million dollars annually in the United States and rely heavily upon PRNP genotyping of sheep. Genetic resistance might reduce goat scrapie and limit the risk of goats serving as a scrapie reservoir, so PRNP coding sequences were examined from 446 goats of 10 breeds, 8 of which had not been previously examined at PRNP. The 10 observed alleles were all related to one of two central haplotypes by a single amino acid substitution. At least five of these alleles (M142, R143, S146, H154, and K222) have been associated with increased incubation time or decreased odds of scrapie. To the best of our knowledge, neither S146 nor K222 has been found in any goats with scrapie, though further evaluation will be required to demonstrate true resistance. S146 was more common, present in several breeds at widely varying frequencies, while K222 was observed only in two dairy breeds at low frequency. Overall, this study provides frequency data on PRNP alleles in US goats, shows the pattern of relationships between haplotypes, and demonstrates segregation of multiple scrapieassociated alleles in several breeds not examined before at PRNP.

Sire Influence on Juniper Consumption by Goats

Abstract Goats avoid eating redberry juniper (Juniperus pinchottii Sudw.) when other palatable forages are available but will increase intake of juniper when exposed to the plant for several days. Intake of redberry juniper also differs among breeds and individual goats. Selection based on foraging habits could further improve juniper intake. The purpose of this study was to determine the influence of sires on juniper consumption. Heritability of redberry juniper intake was assessed for 3 years (1997, 1998, 2000) by placing male Boer-Spanish cross goats from 4–8 sires (the number of sires differed among years) in individual pens and feeding juniper (200 g) daily for 2 hours over 5 to 10 days. Feeding juniper was done after weaning kid goats each year. Juniper intake was similar among sire groups within years. Heritability of juniper consumption was low (11%) across the 3 years of this study. Goats increased juniper intake daily while in individual pens. These results suggest that an acceptance of juniper by goats can be conditioned through exposure to the plant after weaning, and that juniper consumption does not appear to be a highly heritable trait.

Heritability of juniper consumption in 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.