B. R. Min

Gastrointestinal Bacterial and Methanogenic Archaea Diversity Dynamics Associated with Condensed Tannin-Containing Pine Bark Diet in Goats Using 16S rDNA Amplicon Pyrosequencing.

Eighteen Kiko-cross meat goats (n = 6) were used to collect gastrointestinal (GI) bacteria and methanogenic archaea for diversity measures when fed condensed tannin-containing pine bark (PB). Three dietary treatments were tested: control diet (0% PB and 30% wheat straw (WS); 0.17% condensed tannins (CT) dry matter (DM)); 15% PB and 15% WS (1.6% CT DM), and 30% PB and 0% WS (3.2% CT DM). A 16S rDNA bacterial tag-encoded FLX amplicon pyrosequencing technique was used to characterize and elucidate changes in GI bacteria and methanogenic archaea diversity among the diets. Proteobacteria was the most dominant phylum in goats with mean relative abundance values ranging from 39.7 (30% PB) to 46.5% (control) and 47.1% (15% PB). Other phyla individually accounted for fewer than 25% of the relative abundance observed. Predominant methanogens were Methanobrevibacter (75, 72, and 49%), Methanosphaera (3.3, 2.3, and 3.4%), and Methanobacteriaceae (1.2, 0.6, and 0.7%) population in control, 15, and 30% PB, respectively. Among methanogens, Methanobrevibacter was linearly decreased (P = 0.05) with increasing PB supplementation. These results indicate that feeding PB selectively altered bacteria and methanogenic archaeal populations in the GI tract of goats.

Effects of pine bark supplementation on performance, rumen fermentation, and carcass characteristics of Kiko crossbred male goats.

Twenty-two Kiko crossbred male goats (Capra hircus; initial BW = 27.5 ± 1.04 kg) were used in a randomized complete block design to determine the effects of feeding pine bark (PB; Pinus taeda L.) on animal performance, rumen fermentation, blood parameters, fecal egg counts (FEC), and carcass characteristics in goats. Experimental treatments included the control diet [0% PB plus 30% wheat straw (WS)], 15% PB plus 15% WS, and 30% PB plus 0% WS (on as-fed basis), where PB replaced WS. Freshly air-dried PB and WS were finely (1.5 to 3.0 mm) ground and incorporated in the grain mixes. Experimental diets provided a total of 1.9, 16.3, and 32 g of condense tannins (CT)/kg DM in 0%, 15%, and 30% PB diets, respectively. The grain mixes were fed daily at 85% of the feed offered, with remaining 15% consisting of Bermuda grass hay (Cynodon dactylon). Animals were fed once a day at 0800 h, and feed offered and refused was monitored for an 83-d performance period. Rumen and blood samples were collected at d 0, 50, and 80 of the study. Carcass traits were assessed after slaughter at the end of performance period. There was no difference in initial BW, hay, and total NDF intake among treatments; however, final BW (P = 0.06), ADG (P < 0.01), grain mix intake (P < 0.001), total DMI (P < 0.001), and G:F (P < 0.04) increased linearly as the PB increased in the diets. Rumen ammonia N, acetate, isovalerate and acetate-to-propionate ratio were reduced linearly (P < 0.05). There was no difference in carcass traits except cold carcass weight (P = 0.06), which tended to increase linearly in goats fed 15% and 30% PB. Breast, sirloin, trim trait, liver, and hide weight increased (linear; P < 0.01) with addition of PB. Blood basophils, alanine transaminase, aspartate aminotransferase, albumin, Na, and Cl concentrations decreased (linear; P < 0.02 to 0.01) as PB supplementation increased. Supplementation of PB reduced (linear; P < 0.01) average FEC. Addition of PB in the diets improved performance, reduced FEC, and favorably modified rumen fermentation.

Effects of breed and harvest age on feed intake, growth, carcass traits, blood metabolites, and lipogenic gene expression in Boer and Kiko goats.

The objectives of this experiment were to determine the effects of 2 different breeds (BR), Boer and Kiko, and 4 post-weaning harvest ages (HA; Days 0, 29, 56, and 85) on growth, carcass traits, blood metabolites, and lipogenic gene expression. Forty-eight goat (Capra hircus) kids (BW = 23.9 ± 1.50 kg; 3 to 4 mo) were used in a 2 × 4 factorial arrangement of treatments. Goats were stratified by BW within BR and randomly assigned to 4 HA. Kids were born between March 15 and April 7 to purebred does, and were represented by at least 3 purebred sires within each BR. They were fed a grain/hay (80:20) diet once per day. At designated HA, randomly pre-assigned goats (n = 6) from each BR were transported to the Meat Science Lab at Mississippi State University, Starkville, MS, and were harvested. There were no interactions (P > 0.10) between BR and HA. Boer tended (P = 0.08) to have greater initial BW, final BW (P = 0.05), and G/F ratio (P = 0.05). Although the 80:20 grain/hay diet was reinforced by adjusting DMI, both BR had similar total DMI, Boer kept that ratio, while Kiko consumed more (P = 0.001) hay (70:30, grain/hay) and had more (P = 0.001) DMI when expressed as g/kg BW. Boer tended to have greater transportation shrink (P = 0.07), HCW (P = 0.08), and cold carcass weights (CCW; P = 0.08), with greater (P = 0.001) carcass fat. No differences (P > 0.10) were observed in carcass shrink, dressing percentage, 12th rib fat thickness, and LM area between the 2 BR. When expressed as percentage empty BW, carcass bone was similar (P = 0.25), whereas muscle percentage (P = 0.02) was greater for Kiko and fat percentage was greater (P = 0.001) for Boer. Fat as a percentage of CCW remained relatively similar (P > 0.10) for both BR for the 2nd and 3rd HA. Differences were more evident (P = 0.01) at the 4th HA. Boer reached targeted harvest weight (29 kg) at the 3rd HA, while fat deposition continued (P = 0.01) during the 4th HA. Breed had no effect (P > 0.10) on meat color (L*, a*, b*) but HA affected (P = 0.001) all color values. Boer had similar 3-hydroxyl-3-methylglutaryl-CoA synthase mRNA abundance, but was greater (P < 0.03) in acetyl CoA carboxylase compared with Kiko. There was no difference (P = 0.52) in total serum fatty acids (FA, mg/mL) between the 2 BR. As animals aged, their total serum FA increased (P < 0.05) and changed to an undesirable profile. Kiko had a greater (P = 0.02) percentage of muscle and less (P = 0.001) fat in the carcass. We concluded that different BR might need different harvest endpoints and feed input according to consumer acceptability.

Effect of nitrogen fertilisation on diurnal phenolic concentration and foam strength in forage of hard red wheat (Triticum aestivum L.) cv. Cutter

Frothy bloat is a serious digestive disorder in cattle (Bos taurus L.) grazing winter wheat (Triticum aestivum L.) forage in the southern Great Plains of the USA. Wheat plant metabolism is one of the factors involved in bloat. We determined diurnal and seasonal patterns of total phenolic accumulation and foam strength (a measure of bloat potential) in forage of winter wheat cv. Cutter in response to nitrogen (N) fertilisation when grown at Vernon, Texas, during two growing seasons (November–March) in 2006–07 and 2007–08. The diurnal pattern of phenolic accumulation followed the diurnal pattern of solar radiation, with lower values in the morning and the evening, and maximum values around midday. The range of phenolic concentrations measured was 1.9–6.6 mg/g dry matter (tannic acid equivalent). The diurnal pattern of foam strength was opposite to that of phenolic accumulation and ranged from 15.5 to 21.8 min/cm. Nitrogen fertilisation (33, 67, and 134 kg/ha) had inconsistent effects on diurnal patterns of phenolic accumulation and foam strength. With increased N fertilisation rate, concentrations of total, soluble, and insoluble protein fractions increased, whereas soluble carbohydrate concentrations declined. Phenolic concentrations were higher in January–February 2007 and November–December 2007 than in other months and declined in March of each growing season. Foam strength was higher in late autumn than spring in both growing seasons. The results suggest that diurnal patterns of phenolic accumulation in wheat forage respond to diurnal pattern of solar radiation and are inversely correlated with diurnal patterns of foam strength. Breeding wheat cultivars with enhanced phenolic content in forage may be one approach to reduce bloat incidence in grazing cattle.

The Effect of Forage-Based Meat Goat Production Systems on Live Performance, Carcass Traits and Fatty Acid Composition of Kiko Crossbred Goats

It is hypothesize that combining legume forages with grasses will increase plant protein output as well as animal performance. Two years of winter grazing experiments were conducted at the Caprine Research and Education Unit at George Washington Carver Agricultural Experiment Station, Tuskegee University to develop a profitable and sustainable forage-based meat goats production system. Forty-eight Kiko-crossbred (Capra hircus; 19.6±1.5) meat goats were randomly allocated to 6 groups as following: (1) annual ryegrass/wheat (RW; Lolium multiflorum/Triticum aestivum, respectively) + Berseem clover (BC; Trifolium alexandrinum), (2) RW + Austrian pea (AP; Pisum sativum), (3) RW + Hairy vetch (HV; Vicia villosa) + AP, (4) RW + HV + AP + BC, (5) RW + HV, and (6) annual RW as a control with 2 replicates per treatment during 2 years. An average multi-culture forage dry matter (DM; kg/DM/ha) production during 2 years tended to be (P = 0.07) greater for RW+BC than other forage combinations. Biomass production in February and April were higher (P < 0.01) for RW+BC than RW+HV and RW forage combinations, but there was no forage treatment x year interactions. There were no differences in initial body weight (BW), final BW and average daily gain (ADG) among treatments, with no treatment x year interactions for animal BW changes and ADG. However, hot carcass weight, cold carcass weight, and dressing percentage were greater (P<0.05) for RW+BC and RW +HV+AP than for RW grasses. Sirloin weight was greater (P<0.04) for RW+BC than for RW pasture, while leg weight was greater (P < 0.03) for RW+HV + AP than for RW control. Goats grazed on grasses-based diet (RW), had higher average saturated fatty acids (SFA; P < 0.01) and polyunsaturated fatty acids (PUFA; P<0.05) in intramuscular fat content, but both were lower in mescentric kidney fat (MKF) and subcutaneous fat (P < 0.05-0.01) compared to legume forage-based diets. Goats grazed on grass-based diets, had higher omega-3 and -6 fatty acids in intramuscular fat content (P < 0.05-0.08), but both were lower in subcutaneous fat (P < 0.05-0.01) compared to legume forage-based diets. This is probably due to higher nutritive values of forage diets throughout the winter grazing period. The results produced indicated a greater increase in carcass yield with more desirable fatty acids compositions in intramuscular fat content in meat goats from grass-legume multiple combinations compared to mono-culture forage.