Charles T. Gaskins

Effects of breed and sire on carcass characteristics and fatty acid profiles of crossbred wagyu and angus steers.

In a two-year experiment, 54 steers sired by seven Wagyu bulls [American Wagyu Association (AWA) sire numbers 331, 384, 388, 411, 429, 433 and 488] and 15 steers sired by two Angus bulls, all out of Angus-Hereford cows, were used to evaluate the effects of sire and breed on carcass characteristics and fatty acid composition. Steers were given ad-libitum access to a high-concentrate diet (15 % alfalfa cubes and 85 % barley supplement) for at least 170 days. Breed and individual sire effects were analysed. Wagyu-sired steers had higher marbling, maturity and quality scores, more estimated kidney, pelvic and heart fat, larger longissimus dorsi muscle areas, lower fat thicknesses and yield grades than Angus-sired steers (p < 0.05). Steers sired by 388, 411 and 433 had lower fat thicknesses than steers sired by Angus, 429 and 488 (p < 0.05). Steers sired by 384 and 388 had higher marbling scores per cm subcutaneous fat than steers sired by Angus, 429 and 488, and lower fat thickness per 100 kg of carcass weight than Angus-sired steers (p < 0.05). For both subcutaneous fat and longissimus dorsi muscle, Wagyu-sired steers had higher (p < 0.05) percentages of 14:0, 14:1, 16:0, 16:1, and lower percentages of 18:0 than Angus-sired steers. The genetic differences in carcass characteristics among Wagyu sires may enable us to select for improved marbling with less fat in the Wagyu breed. Some statistically significant (p < 0.05) but small differences existed in fatty acid profiles between breeds and among sires.

Effects of biological source on cooking and palatability attributes of beef produced for the Japanese market

Boneless beef loin samples from five biological sources (Japanese Wagyu, American Wagyu (3 4 - 7 8 Wagyu), Angus, Longhorn and US Choice) were evaluated for cooking and palatability attributes as shabu-shabu, steaks and roasts. Japanese Wagyu beef was superior in palatability compared to Angus, Longhorn and US Choice beef when prepared as shabu-shabu or as steaks. Very palatable beef was produced for the Japanese market when the Wagyu breed and a controlled, extended feeding period were utilized. The results were more equivocal when the beef was prepared as roasts, but it is unlikely that a substantial demand for roasts will develop in Japan due to high retail costs and traditions in cookery.

The effect of a shortened dry period on intramammary infections during the subsequent lactation.

Several recent studies have investigated the effect of shortened dry periods on milk production in the subsequent lactation. What is lacking from these studies is an understanding of the effect that a shortened dry period has on udder health. Four herds, 156 cows, were studied to determine if a shortened dry period (30 d) had a negative effect on mammary gland health during the subsequent lactation as opposed to cows assigned to a long, 45 or 60 d, dry period. Cows in 2 herds were assigned to either 30- or 60-d dry periods (group I), whereas cows in the other 2 herds were assigned to either 30- or 45-d dry periods (group II). Intramammary instillation of commercial preparations of cephapirin benzathine, 300 mg (dry cow formulation), was given to cows assigned a 45- or 60-d dry period length protocol, and 200 mg (lactating cow formulation) was administered to cows assigned a 30-d dry period. Differences in response variables to dry period length were compared within group. Cure rates for 60- vs. 30-d dry period cows were 72% (28/39) vs. 81% (30/37) and 74% (25/34) and 73% (27/37) for 45- vs. 30-d dry periods. Differences were not statistically significant for either comparison group. The majority of intramammary infections were caused by the minor pathogens, coagulase-negative staphylococci (n = 102) or Corynebacterium bovis (n = 11). Only 11 cows had intramammary infections by major pathogens. The herd average percentage of new intramammary infections ranged from 6 to 9% and did not differ among herds between treatment groups. Linear somatic cell counts were not significantly affected by dry period length during the first 6 to 7 mo of the subsequent lactation. Milk production did differ between groups. Mature equivalent milk production was greater in group I cows given a 60-d dry period (11,942 +/- 2,059 kg) as opposed to those given a 30-d dry period (10,749 +/- 2,321 kg). Cows given a 45-d dry period did not produce more milk than cows with a 30-d dry period in group II. Although shortening the dry period to 30 d did not have untoward effects on mammary gland health as measured by intramammary infections or milk somatic cell counts, production may be adversely affected when dry periods are shortened to 30 d.

Evaluation of candidate gene effects for beef backfat via Bayesian model selection

Candidate gene approaches provide tools for exploring and localizing causative genes affecting quantitative traits and the underlying variation may be better understood by determining the relative magnitudes of effects of their polymorphisms. Diacyglycerol O-acyltransferase 1 (DGAT1), fatty acid binding protein (heart) 3 (FABP3), growth hormone 1 (GH1), leptin (LEP) and thyroglobulin (TG) have been previously identified as genes contributing to genetic control of subcutaneous fat thickness (SFT) in beef cattle. In the present research, Bayesian model selection was used to evaluate effects of these five candidate genes by comparing competing non-nested models and treating candidate gene effects as either random or fixed. The analyses were implemented in SAS to simplify the programming and computation. Phenotypic data were gathered from a F2 population of Wagyu × Limousin cattle. The five candidate genes had significant but varied effects on SFT in this population. Bayesian model selection identified the DGAT1 model as the one with the greatest model probability, whether candidate gene effects were considered random or fixed, and DGAT1 had the greatest additive effect on SFT. The SAS codes developed in the study are freely available and can be downloaded at: http://www.ansci.wsu.edu/programs/.

Effects of time on feed and post-mortem aging on palatability and lipid composition of crossbred Wagyu beef

Twenty-seven Wagyu-sired steers were fed for 90 (14 steers) or 170 (13 steers) days to study the effects of time on feed on palatability and fatty acid composition, and the effects of post-mortem aging time (2, 4 or 10 days) on palatability. Hot carcass weight, fat thickness, longissimus dorsi muscle area, yield grade, estimated kidney, pelvic and heart fat and maturity score were increased (p < 0.05) by an additional 80 days on the high concentrate feed, but marbling was not changed (p > 0.05). Feeding the high concentrate diet for 170 days increased Warner-Bratzler shear force values (p < 0.05) and tended to decrease tenderness (p > 0.05), flavor intensity and connective tissue scores. For the 90 day feeding group, 4 days of aging improved connective tissue score (p < 0.05) and tended to increase (p > 0.05) tenderness scores and decrease shear force, compared with 2 days of aging. For the 170 day feeding group, 10 days of aging improved (p < 0.05) shear force and all sensory attributes except flavor intensity, compared to 2 days of aging. An additional 80 days on feed decreased (p < 0.05) stearic acid and total saturated fatty acids (SFA) and generally increased (p < 0.05) monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), MUFA:SFA, and PUFA:SFA in subcutaneous fat and longissimus dorsi muscle. The cholesterol content of fat and muscle increased (p < 0.05) as time on feed increased. Ninety days on a high concentrate diet was adequate for yearling crossbred Wagyu steers to produce highly acceptable carcasses. The additional 80 days on feed produced little or no overall benefit and the steers became overfinished and less tender. Ten days post-mortem aging improved (p < 0.05) all palatability attributes except flavor intensity.

Modeling animal-unit-equivalents for beef cattle

Abstract The process of formalizing objectives and defining assumptions in calculating animal-unit-equivalents (AUE) for different classes of beef cattle is discussed. Relationships among energy demand, forage supply, intake and animal-units are examined. An example is presented of an AUE model with two levels of complexity adapted from a model of total digestible nutrient (TDN) requirements. Standardization of approaches is needed in calculating AUEs, and the stocking variables derived from them. Such formalization improves communication, applicability and contributes to scientific grazing management.

Quantitative genomics of 30 complex phenotypes in Wagyu x Angus F₁ progeny.

In the present study, a total of 91 genes involved in various pathways were investigated for their associations with six carcass traits and twenty-four fatty acid composition phenotypes in a Wagyu×Angus reference population, including 43 Wagyu bulls and their potential 791 F1 progeny. Of the 182 SNPs evaluated, 102 SNPs that were in Hardy-Weinberg equilibrium with minor allele frequencies (MAF>0.15) were selected for parentage assignment and association studies with these quantitative traits. The parentage assignment revealed that 40 of 43 Wagyu sires produced over 96.71% of the calves in the population. Linkage disequilibrium analysis identified 75 of 102 SNPs derived from 54 genes as tagged SNPs. After Bonferroni correction, single-marker analysis revealed a total of 113 significant associations between 44 genes and 29 phenotypes (adjusted P<0.05). Multiple-marker analysis confirmed single-gene associations for 10 traits, but revealed two-gene networks for 9 traits and three-gene networks for 8 traits. Particularly, we observed that TNF (tumor necrosis factor) gene is significantly associated with both beef marbling score (P=0.0016) and palmitic acid (C16:0) (P=0.0043), RCAN1 (regulator of calcineurin 1) with rib-eye area (P=0.0103), ASB3 (ankyrin repeat and SOCS box-containing 3) with backfat (P=0.0392), ABCA1 (ATP-binding cassette A1) with both palmitic acid (C16:0) (P=0.0025) and oleic acid (C18:1n9) (P=0.0114), SLC27A1(solute carrier family 27 A1) with oleic acid (C18:1n9) (P=0.0155), CRH (corticotropin releasing hormone) with both linolenic acid (OMEGA-3) (P=0.0200) and OMEGA 6:3 RATIO (P=0.0054), SLC27A2 (solute carrier family 27 A2) with both linoleic acid (OMEGA-6) (P=0.0121) and FAT (P=0.0333), GNG3 (guanine nucleotide binding protein gamma 3 with desaturase 9 (P=0.0115), and EFEMP1 (EGF containing fibulin-like extracellular matrix protein 1), PLTP (phospholipid transfer protein) and DSEL (dermatan sulfate epimerase-like) with conjugated linoleic acid (P=0.0042-0.0044), respectively, in the Wagyu x Angus F1 population. In addition, we observed an interesting phenomenon that crossbreeding of different breeds might change gene actions to dominant and overdominant modes, thus explaining the origin of heterosis. The present study confirmed that these important families or pathway-based genes are useful targets for improving meat quality traits and healthful beef products in cattle.