Factors influencing the feeding behavior of goats include grazing management practices, type of vegetation and season, breed and stage of production, group size, and properties of diets fed in confinement. Considerable information has been gathered from visual observation during daylight. However, tools are now available to characterize the feeding behavior of goats while grazing and while in confinement throughout the day. Global positioning system collars can be used to assess horizontal and vertical distances traveled, up or down position of the head, and movement within pasture or rangeland areas. A commercially available leg activity monitor allows estimation of the number of steps and time spent standing, lying, and moving rapidly without grazing. However, these measurements do not directly determine grazing. Therefore, prediction equations based on visual observation must be developed. Classification tree analysis is a robust method in developing these equations because the decision tree can be pruned or expanded to provide the best fit. Another equipment system determines time spent eating, ruminating, and remaining idle from the pattern of jaw movement. In addition to use of n-alkanes as internal markers to estimate digestibility, their profile can provide an indication of the botanical composition of the selected diet. Automated feeding systems for confined goats permit determinations such as number of feeder visits and meals, eating time, and rate and pattern of feed intake. Heart rate measured while goats are in normal production settings can be used to predict total energy expenditure through multiplication by energy expenditure per heartbeat of individual animals. To partition the activity energy cost, an estimate of ME intake or measures of changes in body energy status and milk energy yield are needed to determine other sources of heat to be subtracted from total energy expenditure. These methods create the opportunity to gain a fuller understanding of factors influencing the feeding behavior of goats and the relationships with levels and efficiencies of production. Copyright © 2010. American Society of Animal Science .

Background: Gastrointestinal nematode infection (GNI) is the most important disease affecting the small ruminant industry in U.S. The environmental conditions in the southern United States are ideal for the survival of the most pathogenic gastrointestinal nematode,Haemonchus contortus. Host genetic variation for resistance toH. contortusallows selective breeding for increased resistance of animals. This selection process increases the prevalence of particular alleles in sheep and goats and creates unique genetic patterns in the genome of these species. The aim of this study was to identify loci with divergent allelic frequencies in a candidate gene panel of 100 genes using two different approaches (frequentist and Bayesian) to estimateFst outliers in three different breeds of sheep and goats exposed toH. contortus.Results: Our results for sheep populations showed SNPs under selection inC3AR1,CSF3,SOCS2,NOS2,STAT5B,TGFB2andIL2RAgenes using frequentist and Bayesian approaches. For goats, SNPs inCD1D,ITGA9,IL12A,IL13RA1, CD86andTGFB2genes were under selection. Common signatures of selection in both species were observed inNOS2,TGFB2andTLR4genes. Directional selection was present in all SNPs evaluated in the present study.Conclusions: A total of 13 SNPs within 7 genes of our candidate gene panel related toH. contortusexposure were identified under selection in sheep populations. For goats, 11 SNPs within 7 genes were identified under selection. Results from this study support the hypothesis that resistance toH. contortusis likely to be controlled by many loci. Shared signatures of selection related to mechanisms of immune protection againstH. contortusinfection in sheep and goats could be useful targets in breeding programs aimed to produce resistant animals with low FEC.

Twenty-four yearling Boer × Spanish wethers were used to assess effects of different forages, either fresh (Exp. 1) or as hay (Exp. 2), on feed intake, digestibilities, heat production, and ruminal methane emission. Treatments were: 1) Sericea lespedeza (SER; Lespedeza cuneata), a legume high in condensed tannins (CT; 20% and 15% in fresh forage and hay, respectively), 2) SER supplemented with polyethylene glycol (SER-PEG; 25 g/d), 3) alfalfa (Medicago sativa), a legume low in CT (ALF), and 4) sorghum-sudangrass (Sorghum bicolor), a grass low in CT (GRASS). Experiments were 22 d, which included 16 d for acclimatization followed by a 6-d period for fecal and urine collection, and gas exchange measurement (last 2 d). Intake of OM was 867, 823, 694, and 691 g/d (SEM = 20.1) with fresh forage, and 806, 887, 681, and 607 g/d with hay for SER, SER-PEG, ALF, and GRASS, respectively (SEM = 46.6). Apparent total tract N digestion was greater for SER-PEG vs. SER (P < 0.001) with fresh forage (46.3%, 66.5%, 81.7%, and 73.2%; SEM = 1.71) and hay (49.7%, 71.4%, 65.4%, and 54.8% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.57). Intake of ME was similar among treatments with fresh forage (8.24, 8.06, 7.42, and 7.70 MJ/d; SEM = 0.434) and with hay was greater for SER-PEG than ALF (P < 0.03) and GRASS (P < 0.001) (8.63, 10.40, 8.15, and 6.74 MJ/d for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.655). The number of ciliate protozoa in ruminal fluid was least for SER with fresh forage (P < 0.01) (9.8, 20.1, 21.0, and 33.6 × 10⁵/ml; SEM = 2.76) and hay (P < 0.02) (6.3, 11.4, 13.6, and 12.5 × 10⁵/ml for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.43). Methane emission as a percentage of DE intake was lower (P < 0.01) for SER vs. ALF and GRASS with fresh forage (6.6, 8.3, 9.4, and 9.2%; SEM = 0.64) and hay (4.3, 4.9, 6.4, and 6.7% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.38). In summary, methane emission in this short-term experiment was similar between a legume and grass low in CT as fresh forage and hay. The CT in SER markedly decreased N digestibility and elicited a moderate decline in ruminal methane emission. Supplementation with PEG alleviated the effect of CT on N digestibility but not ruminal methane emission, presumably because of different modes of action. In conclusion, potential of using CT-containing forage as a means of decreasing ruminal methane emission requires further study, such as with longer feeding periods. Copyright © 2012. American Society of Animal Science .