Influence of beef genotypes on animal performance, carcass traits, meat quality, and sensory characteristics in grazing or feedlot-finished steers.

A 2-yr study was conducted to evaluate the effects of beef genotypes and feeding systems on performance, carcass traits, meat quality, and sensory attributes. A 2×2 factorial experiment was used to randomly allocate 60 steers in year 1 (YR1) and 44 steers in year 2 (YR2). The two beef genotypes evaluated were Red Angus (RA), and RA x Akaushi (AK) crossbreed. The steers were allotted to two finishing feeding systems: grazing, a multi-species forage mixture (GRASS) and feedlot finishing, conventional total mixed ration (GRAIN). All steers were slaughtered on the same day, at 26 and 18 mo of age (GRASS and GRAIN, respectively), and carcass data were collected 48 h postmortem. Growth and slaughter characteristics were significantly impacted by the finishing system (P < 0.01), with the best results presented by GRAIN. Beef genotype affected dressing percent (P < 0.01), ribeye area (P = 0.04), and marbling score (P = 0.01). The AK steers had a tendency (P = 0.09) for lower total gain; however, carcass quality scores were greater compared to RA. There was a genotype by system interaction for USDA yield grade (P < 0.01), where it was lower in GRASS compared to GRAIN in both genotypes, and no difference was observed between the two genotypes for any GRASS or GRAIN systems. There was no difference in meat quality or sensory attributes (P > 0.10) between the two genotypes, except that steaks from AK tended to be juicier than RA (P = 0.06). Thawing loss and color variables were impacted by the finishing system (P < 0.01). L* (lightness) and hue angle presented greater values while a* (redness), b* (yellowness), and chroma presented lower values in GRAIN compared to GRASS. Sensory attributes were scored better in GRAIN than GRASS beef (P < 0.01). There was a genotype by system interaction for flavor (P = 0.02), where beef from RA had a lower flavor rating in GRASS than in GRAIN, and no difference was observed for AK. Within each system, no difference was observed for flavor between RA and AK. Beef from steers in GRASS had greater (P < 0.01) WBSF than those from GRAIN. These results indicate that steers from GRAIN had superior performance and carcass merit and that AK enhanced these traits to a greater degree compared to RA. Furthermore, the beef finishing system had a marked impact on the steaks' sensory attributes and consumer acceptability. The favorable results for texture and juiciness in GRAIN, which likely impacted overall acceptability, may be related to high marbling.

Carcass parameters and meat quality in meat-goat kids finished on chicory, birdsfoot trefoil, or red clover pastures.

This study was conducted during the 2009 and 2010 grazing seasons to assess carcass parameters and chevon (goat meat) quality when meat-goat kids (n=72) were finished on pastures of red clover (Trifolium pratense L.; RCL), birdsfoot trefoil (Lotus corniculatus L.; BFT), or chicory (Cichorium intybus L.; CHIC). Final live weight (P<0.05) and carcass weight (P=0.10) were greater when goats were finished on RCL compared to CHIC with BFT being intermediate. Ribeye area, backfat thickness, body wall thickness, internal fat score, and leg score were not different (P>0.10) among treatments when adjusted for the covariate of carcass weight. Finishing meat-goat kids on RCL, BFT, or CHIC impacted concentrations of fatty acids (FAs) 18:1 trans-10, 18:1 cis-11, 18:2, 18:3 polyunsaturated fatty acids (PUFAs), omega-6, omega-3, and PUFA:saturated fatty acid ratio in longissimus lumborum samples. Finishing meat-goat kids on CHIC, RCL, or BFT pastures produced carcass weights acceptable for most ethnic markets in the USA.

Meat goat kids finished on alfalfa, red clover or orchardgrass pastures: carcass merit and meat quality.

This experiment was conducted in 2005-2007 to evaluate carcass and chevon (goat meat) quality parameters when meat-goat kids (n=72) were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pratense L.; RCG); or orchardgrass (Dactylis glomerata L.; OGR) pastures. Carcass conformation score was greater (P=0.08) when meat-goat kids were finished on ALF compared to OGR with RCG intermediate. Chevon meat samples from goats finished on the three pasture treatments did not differ in ash, intramuscular fat, or crude protein content or in concentrations of omega6 and omega3 fatty acids, or the omega6 to omega3 ratio. Goats finished on OGR had higher (P<0.001) 18:1 trans-11 fatty acids (FA) compared to ALF or RCG. Overall, meat-goat kids finished on ALF, RCG, or ORG produced desirable carcass weights for most niche markets in the USA. Chevon is a low-fat meat option with high desirable fatty acids for human diets.

Carcass merit and meat quality in Suffolk lambs, Katahdin lambs, and meat-goat kids finished on a grass-legume pasture with and without supplementation.

The experiment evaluated traditional U.S. sheep (Suffolk), hair sheep (Katahdin), and meat goat (Boer crossbred; Goat) carcass and meat quality parameters when finished on pasture with and without supplemental whole cottonseed (Gossypium hirsutum L.). Supplemented animals had greater ribeye area (P<0.01), body wall thickness (P<0.001), and lean quality score (P<0.05) than unsupplemented animals. Whole cottonseed increased fatty acids (FA) 18:1 trans-10, 18:1 trans-12, 18:2, and Omega6:Omega3 ratio and decreased FA 18:1 trans-11, 18:3, and Omega3 in longissimus muscle (LM). Katahdin LM had greater (P<0.001) intramuscular fat compared to Suffolk and Goat. Goat LM had less (P<0.001) FA 14:0, 18:0, 18:1 t11, 18:3, 20:3n-6, and saturated FA when compared to Suffolk or Katahdin. Carcass weights from pasture-finished sheep and goats would be acceptable for most ethnic markets in the USA. Omega6:Omega3 ratios in chevon and lamb were within the guidelines for meats that can improve human diets and health.

Recirculating elutriator for extracting gastrointestinal nematode larvae from pasture herbage samples.

Gastrointestinal nematode (GIN) parasites present an important limitation to ruminant production worldwide. Methods for quantifying infective larvae of GIN on pastures are generally tedious, time-consuming, and require bulky equipment set-ups. This limitation to expedient data collection is a bottleneck in development of pasture management practices that might reduce pasture infectivity. We modified a soil elutriator concept for extracting GIN larvae from fresh herbage samples. Elutriators were constructed from readily available parts and compared to the Baermann funnel sedimentation method for larvae extraction. More samples could be extracted per day in the elutriator than in a Baermann unit with extraction times of 8 min versus 24h, respectively. Accuracy, measured as maximum recovery of larvae seeded onto herbage samples, did not differ between extraction methods (62.3 vs. 69.8% for elutriator and Baermann, respectively, P>0.05). Larvae recovery from herbage in elutriators showed a strong log(e) relationship with extraction time (r(2)>0.98), which will allow development of accurate correction factors for specific herbages to predict total larvae densities at extraction times less than those needed for maximum recovery. An extraction time of 8 min per sample gave the best compromise of speed, accuracy, and precision as measured by regression confidence bands and root mean square error of analysis of variance. Precision of the elutriator extraction for pasture samples was comparable to published methods and was not affected by forage species or canopy strata. The elutriator method was sensitive enough to detect differences in larvae density as small as 8 larvae g(-1) DM among pasture treatments. Elutriators extracted nematode larvae from herbage samples with accuracy and precision similar to existing methods, but did it much faster. Elutriation shows promise as a rapid method for extracting infective GIN larvae from pasture herbage.

Winter-annual pasture as a supplement for beef cows.

In each of two experiments, 120 pregnant beef cows were stratified by body condition score, BW, breed, and age, randomly divided into six groups of 20, and assigned to one of six 5.1-ha bermudagrass (Cynodon dactylon [L.] Pers.) pastures (two replicates/ treatment) in early January to evaluate the use of winter-annual pasture as a supplement. All cows in Exp. 1 and 2 had ad libitum access to bermudagrass/dallisgrass (Paspalum dilatatum Poir.) hay plus three treatments: 1) a concentrate-based supplement fed 3 d/wk, 2) limit grazing on winter-annual pasture 2 d/wk (7 hr/ d; 0.04 ha x cow(-1) x grazing d(-1)), or 3) limit grazing on winter-annual pasture 3 d/wk (7 hr/d; 0.04 ha x cow(-1) x grazing d(-1)) sod-seeded into a portion of the pasture until mid-May. The seeded portion of pastures in Exp. 1 was planted with a mixture of wheat (Triticum aestivum L.) and rye (Secale cereale L.), but annual ryegrass (Lolium multiflorum Lam.) was added to the seed mixture in Exp. 2. In mid-May, cows were blocked by treatment and the previous sorting factors, randomly assigned to six new groups of 20, and placed on the six perennial pastures until calves were weaned. Groups of cows were exposed to a bull for 60 d beginning in mid-May. In Exp. 1 and 2, limit-grazing winter-annual pasture compared to the concentrate-based supplement or limit grazing 2 vs 3 d/wk did not affect (P > 0.15) cow BW. In Exp. 1, cows limit grazed on winter-annual pasture had a lower (P = 0.05) body condition score than cows fed the concentrate-based supplement in the early spring. However, in Exp. 2, cows limit grazed on winter-annual pasture had higher (P < or = 0.07) body condition score than cows fed the concentrate-based supplement. The conception rate of cows in Exp. 1 and 2 did not differ (P > 0.22) between cows fed concentrate-based supplements and cows limit grazed on winter-annual pasture. In Exp. 2, cows limit grazed 2 d/wk tended to have a greater (P = 0.10) conception rate than cows limit grazed 3 d/wk. In Exp. 1 and 2, birth weight, total gain, BW, and ADG of calves were not affected (P > 0.15) by treatment. We conclude that wheat and rye pasture is a marginal supplement for lactating beef cows. However, cows limit grazed 2 d/wk on winter-annual pasture of wheat, rye, and annual ryegrass as a supplement maintained BW and body condition score as well as cows fed the concentrate-based supplement. But, grazing pasture 3 vs 2 d/wk did not seem to affect performance of cows.

Feed intake and apparent digestibility of hay-supplemented brassica diets for lambs.

Animal performance on brassica diets often does not reflect laboratory estimates of the nutritive value of the herbage. Hay supplementation of brassica pastures should increase diet DM and fiber intake and dilute anti-quality factors. The optimal hay:brassica ratio needed to achieve desirable animal performance, however, has not been established. Effects of changing the hay:brassica ratio on feed and water intake, apparent digestibility of diets, thyroid status, and anemia were examined in five Dorset-cross wether spring lambs (initial BW 32.8 +/- 3.2 kg). The experimental design was a 5 x 5 Latin square with 21-d periods (7 d of adaptation, 6 d of intake measurement, and an 8-d digestion trial with jugular blood drawn on last day). Diets contained chopped grass hay and tyfon (turnip x Chinese cabbage hybrid) at five hay:tyfon ratios (DM basis): 100:0; 75:25; 50:50; 25:75; and 0:100. As the proportion of tyfon in the diet increased, there were linear increases (P < .05) in ad libitum DMI (922 to 1,359 g/d), total water intake (1.75 to 13.06 L/d), digestible DMI (401 to 952 g/d), and apparent digestibility of DM (55.9 to 86.3%), CP (52.9 to 84.5%), and neutral detergent solubles (57.2 to 88.5%). Hay plus tyfon diets exhibited negative associative effects for apparent digestibility of NDF, ADF, and cellulose. Plasma thyroxine and triiodothyronine, packed cell volume, red blood count, and hemoglobin concentration were not affected by diet. Tyfon influenced DMI and apparent digestibility of diets in a manner similar to that of a concentrate.

Sodium sesquicarbonate for early lactation dairy cows fed corn silage-based diets.

An experiment was conducted to evaluate the effects of dietary sodium sesquicarbonate on milk production and composition, feed intake, ruminal fermentation, and urine pH and composition in 32 multiparous Holstein cows in early lactation. Cows were fed high energy diets of 50% corn silage: 50% concentrate containing 0 or .75% sodium sesquicarbonate (total ration DM basis) for 84 d postpartum. Sodium sesquicarbonate increased milk fat percentage (3.46 vs. 3.27%), milk fat yield (1.39 vs. 1.26 kg), and 4% FCM yield (37.1 vs. 34.7 kg) but did not affect milk yield, milk protein percentage or yield, feed intake, ruminal fluid pH, or ruminal VFA profile. Urine composition was not affected by sodium sesquicarbonate, but urine pH (8.14 vs. 8.04) and total urine output as estimated by creatinine concentration were higher than that of controls. In summary, sodium sesquicarbonate, added as .75% of the ration DM, was effective in improving milk fat percentage, milk fat yield, and 4% FCM yield in early lactation dairy cows fed corn silage-based diets.

Eating and resting salivation in early lactation dairy cows.

Salivation rates were measured by cardial collection in four ruminally fistulated, early lactation cows. Complete diets of 70% concentrate: 30% hay crop silage (dry matter) or an isonitrogenous, isocaloric mixture of 60% concentrate: 40% corn silage were fed ad libitum once daily in a replicated 2 X 2 Latin square design. Thirty-day periods, beginning 2 d postpartum, consisted of 22 d adaptation and 8 d for determination of eating behavior, eating and resting salivation rates, and rumen liquid turnover rate. Diet did not affect eating behavior, salivation rates, saliva volumes produced while eating or resting, or saliva composition, but degree of feed ensalivation (fresh basis) and volume of saliva per bolus were higher for the hay crop silage diet due to its higher dry matter content. Resting salivation rate and volume produced while resting were greater at wk 8 than wk 4 of lactation even when corrected to constant dry matter intake, indicating that adaptation to diet postpartum involved increased basal resting salivation rate. Rumen pH was lower for the hay crop silage diet, but rumen fluid kinetic measurements did not differ with diet or week of lactation.