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A total of 689 co-grazing small ruminants along with 446 wild-living birds were tested during two springs and autumns (2007–2009) under two management systems at two Mid-Atlantic locations (~187 km in aerial distance) of the U.S. Fecal shedding of Campylobacter jejuni and Salmonella spp. were, respectively, detected in 9.3% and 3.5% of small ruminants and in 7.4% and 0.2% of wild-living birds. Sheep had a significantly higher prevalence of C. jejuni and Salmonella than goats, but there were no differences due to season, location, or management. Pulsed field gel electrophoresis (PFGE) of isolated strains revealed geographic specificity and genomic diversity of both pathogens from small ruminants. However, C. jejuni strains with indistinguishable PFGE profiles were isolated from one Rock Dove and two European Starlings caught at separate locations. Matching C. jejuni or Salmonella strain profiles were not found between small ruminants and wild-living birds. This study found that sheep pose a greater risk than goats in C. jejuni and Salmonella contamination at co-grazing small ruminant farms. Wild-living birds also are potential carriers of C. jejuni and Salmonella although no evidence of cross-contamination with small ruminants was established.

Objectives of this study were to determine if a redberry juniper-based diet can reduce fecal egg counts (FEC) and increase ivermectin (IVM) efficacy in IVM-resistant Haemonchus contortus. Predominant genera present were Haemonchus (range 45-100%) and Trichostrongylus (range 0-47%). The FEC reduction for IVM in the ewe flock was 25% (95% confidence intervals 79% to -162%) and confirmed IVM resistance. After natural infection was established, Barbados Blackbelly and St. Croix lambs (n=64, 6 months old) were randomly assigned to pens and fed a pelleted treatment diet (4 pens/treatment and 8 lambs/pen) consisting of traditional feed ingredients mixed with either 30% hay (CNTL) or 30% ground juniper leaves and stems (JUN). Lambs were fed during two periods: Period 1 (days 0-28) and Period 2 (days 28-42). On day 28, half of the lambs from each treatment and pen were treated with IVM orally (0.2 mg/kg), creating four treatment groups: lambs fed CNTL or JUN and either not treated (CNTLn, JUNn) or treated (CNTLi, JUNi) with IVM. During Period 1, lambs fed CNTL had greater (P0.001) average daily gain than lambs fed JUN, which was probably caused by the CNTL diet having greater protein and less acid detergent fiber, lignin, and condensed tannins than the JUN diet. Lambs had similar (P0.46) FEC on days 0 and 28, but lambs fed JUN had 69.1% lower (P0.001) FEC on day 15 as compared to lambs fed CNTL. During Period 2, CNTLi lambs had greater (P0.05) average daily gain than JUNn and JUNi lambs. Lambs fed JUN and treated with IVM (JUNi) had 66%, 65%, and 61% lower (P0.05) FEC as compared to CNTLn, CNTLi, and JUNn lambs, respectively. Results suggest that feeding lambs a diet containing 30% redberry juniper reduced FEC and increased IVM efficacy by 65% (JUNi vs. CNTLi). Specific mechanisms involved in increasing IVM efficacy by feeding diets containing bioactive compounds warrants further investigation.

A metabolism (Experiment 1; n = 18) and a pen feeding (Experiment 2; n = 24) study were conducted to determine dry matter intake (DMI); in vivo dry matter (DM), organic matter (OM), nitrogen (N), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility, N use, and performance of three genetic types of meat goats offered high forage diets. In both experiments, 7 mo old castrate male goat kids, equally representing the F 1 Boer × Spanish (BoerX; avg wt 21 kg), Kiko × Spanish (KikoX; avg wt 26 kg) and Spanish (avg wt 20 kg) genetic types, were offered chopped alfalfa ( Medicago sativa L.) hay with an 80% corn ( Zea mays L.)-18% soybean [ Glycine max (L.) Merr.] meal supplement. In Exp. 1, goats were offered alfalfa hay plus supplement at 0.5% BW. Total DMI hay intake among the three breed types was variable, but was higher ( P = 0.05) for KikoX compared to Spanish; BoerX was intermediate. Apparent in vivo digestibility coefficients for DM, OM, N, NDF, and ADF were not different ( P > 0.10). Blood glucose concentrations were similar for Spanish and KikoX (mean 70.3 mg/dl), but both were higher ( P P P > 0.10) among breeds (93 g/d). More research is needed that evaluates forage-supplement interactions, metabolic differences, and physiological changes among meat goats in order to optimize nutrient-use efficiency and performance.

Widespread anthelmintic resistance in small ruminants has necessitated alternative means of gastrointestinal nematode (GIN) control. The objective was to determine the effectiveness of copper oxide wire particles (COWP) administered as a gelatin capsule or in a feed supplement to control GIN in goats. In four separate experiments, peri-parturient does (n=36), yearling does (n=25), weaned kids (n=72), and yearling bucks (n=16) were randomly assigned to remain untreated or administered 2g COWP in a capsule (in Experiments 1, 2, and 3) or feed supplement (all experiments). Feces and blood were collected every 7 days between Days 0 and 21 (older goats) or Day 42 (kids) for fecal egg counts (FEC) and blood packed cell volume (PCV) analyses. A peri-parturient rise in FEC was evident in the untreated does, but not the COWP-treated does (COWP x date, P

The objectives of this study were to estimate the: (1) the daily manure (feces + urine) outputs by goats and sheep and characterize the nutrient composition, and (2) potential contribution of goats and sheep to the nutrients in the Chesapeake Bay Watershed (Bay) watershed. Manure (feces+ urine) was collected from four 8-month-old mixed-breed hair sheep rams and four 14-month-old meat goat bucks housed in aluminum metabolism crates with rubber-coated expanded metal floors. The animals were fitted with fecal collection bags. Animals were fed a diet of chopped grass hay (75%) and corn/soybean meal concentrates (25%). The animals' numbers in the Chesapeake Bay watershed were obtained from USDA national agricultural animal census database. The manure nutrients excreted by the goats and sheep were compared to those of dairy cows in the watershed to get a feel for the relative impacts. The nitrogen (N), phosphorus (P), and potassium (K) ratios were 8.8:1:6.5 and 8.3:1:6.9, in goat and sheep manure respectively, and over 50% of N and K were in the urine. The goat population in the Bay watershed increased by over 200% between 1997 and 2007, while the sheep population declined by about 10% over the same period of time. Based on the animal census for 2007 in the Bay watershed, the combined N and P excreted by goats and sheep combined were less than 3% of the nutrients excreted by dairy cows.

Pen feeding and metabolism trials were conducted to determine intake, diet digestibility and nitrogen (N) use in three hair sheep breeds with differing growth potential offered an alfalfa hay diet. For pen feeding, 24 6-mo-old wether lambs, equally representing the Barbados Blackbelly, Katahdin, and St. Croix breeds, were paired by breed, placed in 12 enclosed cement-floor pens (2.5 m × 3.5 m), and offered chopped alfalfa (Medicago sativa L.; 17.6% CP, 50.4% NDF, and 36.4% ADF) ad libitum. Lambs were allowed a 14-d adaptation period to pens and diets, and remained on trial for 56 d. Starting body weight (BW) was different (P 0.10) among breeds. Six lambs per breed were used in the metabolism trial. Total DMI was greater (P 0.10) adjusted for body weight (mean: 71 g/kg BW0.75). Coefficients of apparent digestibility for DM (P 0.10) among breeds. Breeds differed in their growth performance in line with breed mature size, and differences were observed in N digestibility and absorption.

July-born F1 Boer x Spanish (BoerX), Nubian, and Spanish buck kids (n = 18) were used in an experiment to evaluate the use of lespedeza hay in goat diets. Bucklings were weaned at 60 d of age and maintained on pasture and in pens, before being assigned to the experiment at 6 months of age. Kids were randomly assigned to six pens and stratified by breed. The two diets were ad libitum: (1) sericea lespedeza [Lespedeza cuneata (Dum.-Cours) G. Don; LESP] hay, or (2) alfalfa (Medicago sativa L.; ALF) hay. All animals received a 16% crude protein (CP) corn/cottonseed-based supplement offered at 0.5% of body weight (BW) per head/d. Total dry matter intake (DMI) was higher (P 0.10) in ADG (mean 79 g/d). Bucks offered the ALF-based diet had higher (P < 0.001) plasma concentrations (mg/dl) of blood urea nitrogen (BUN; 21.1 versus 10.7) and glucose (67.7 versus 59.5) and lower (P < 0.001) creatinine (0.53 versus 0.62 mg/dl) compared to kids offered the LESP-based diet. Blood glucose concentrations were highest (P < 0.001) for Nubian (66.3 mg/dl) and lowest for Boer cross (60.9 mg/dl); Spanish was intermediate (63.6 mg/dl). Creatinine levels were similar among breeds (mean 0.57 mg/dl). More research is needed to evaluate goat breed, forage species, stage of forage maturity, condensed tannins, and supplementation effects on nutrient utilization by finishing goats.

Understanding existing levels of genetic diversity of sheep breeds facilitates in situ and ex situ conservation activities. A comprehensive evaluation of US sheep breeds has not been previously performed; therefore, we evaluated the genetic diversity among and within 28 US sheep breeds. Both major and minor breeds were included in the analysis and consisted of 666 animals from 222 producers located in 38 states. The level of within-breed genetic diversity was variable and not dependent upon status of a breed as a major or minor breed. Bayesian cluster analysis indicated the breeds were grouped more by physiological differences (meat vs. wool production) rather than geographic origin. Results suggest several actionable items to improve in situ and ex situ conservation. The results clearly identify breeds in need of increased in situ and ex situ management (e.g., Hog Island and Karakul) and allow several suggestions for in situ management of flocks. Conversely, several of the breeds appear genetically similar and therefore require less emphasis on collecting germplasm samples for the gene bank. Commercially important breeds (e.g., Rambouillet and Suffolk) were found to have substantial variation, which should enable breeders to proceed, unencumbered by genetic diversity concerns, with selection strategies that maximize profit.

Performance and carcass characteristics of St. Croix lambs fed chopped forage, predominantly guineagrass (Panicum maximum), was evaluated in three 60-d trials. Treatments in trial 1 were chopped guineagrass ad libitum only (CONT), CONT plus coconut meal (COCO) and CONT plus fish meal (FISH). Supplements (SUPP) were offered at the rate of 9 g CP·kg body weight (BW)−1·d−1. Treatments in trial 2 were guineagrass fed ad libitum and molasses fed at the rate of 10 g·kg BW−1·d−1 (MCONT), MCONT plus coconut meal (MCOCO) and MCONT plus fish meal (MFISH), SUPP offered at the rate of 4 g CP·kg BW−1·d−1. Treatments in trial 3 were MCONT and MCONT plus a 3:1 (C3F1) or 1:3 (C1F3) mixture of coconut meal and fish meal offered at 1o g·kg BW−1·d−. In trial 1, CONT (forage only) lambs lost weight (−0.056 kg/d), while SUPP lambs gained slightly (0.024 to 0.133 kg/d). Apparent digestibilities, particularly for N, were improved with SUPP, but were not different between COCO and FISH. With the addition of molasses to all diets in trial 2, weight gains were all positive, were higher in SUPP compared with MCONT (P

Testicular characteristics were measured in a random population of Senepol bulls representing three farms on St. Croix (17°N, 64°W), during a 5 year period. Bulls were maintained on native, tropical grass/legume pasture throughout all stages of development. Scrotal circumference (SC; 317 measurements, 267 bulls) increased in a curvilinear relationship (P < 0.001) with both age (r2 = 0.816) and body weight (r2 = 0.856) and reached a mean maximum SC of 42.4 cm at 6–7 years of age. There was a linear relationship (n=84; P

Serum and liver concentrations of selected macro-and trace minerals were determined in Senepol cattle at 8 sites (4 each in a high and low rainfall region) during the dry and wet season on St Croix. At each site an average of 15 mature, lactating cows, grazing native grass/legume pastures without supplementation were blood sampled each season. Liver samples were collected (n=51) at slaughter from mature animals originating from the same sites. A preliminary analysis indicated no differences in serum mineral concentrations between mature lactating cows and growing heifers. There were differences between sites for serum magnesium (Mg) (P

Variance and covariance components were estimated for weaning weight from Senepol field data for use in the reduced animal model for a maternally influenced trait. The 4,634 weaning records were used to evaluate 113 sires and 1,406 dams on the island of St. Croix. Estimates of direct additive genetic variance (sigma 2A), maternal additive genetic variance (sigma 2M), covariance between direct and maternal additive genetic effects (sigma AM), permanent maternal environmental variance (sigma 2PE), and residual variance (sigma 2 epsilon) were calculated by equating variances estimated from a sire-dam model and a sire-maternal grandsire model, with and without the inverse of the numerator relationship matrix (A-1), to their expectations. Estimates were sigma 2A, 139.05 and 138.14 kg2; sigma 2M, 307.04 and 288.90 kg2; sigma AM, -117.57 and -103.76 kg2; sigma 2PE, -258.35 and -243.40 kg2; and sigma 2 epsilon, 588.18 and 577.72 kg2 with and without A-1, respectively. Heritability estimates for direct additive (h2A) were .211 and .210 with and without A-1, respectively. Heritability estimates for maternal additive (h2M) were .47 and .44 with and without A-1, respectively. Correlations between direct and maternal (IAM) effects were -.57 and -.52 with and without A-1, respectively.

Data (3,710 observations) were collected from two farms by the Virgin Islands Agricultural Experiment Station from 1978 to 1987. Data were analyzed to determine the adequacy of standard Beef Improvement Federation (BIF) age of dam (AOD) and calf sex (SEX) adjustment factors for 205-d weaning weight (WWT) for use on Senepol cattle. The mixed model contained the random effect of contemporary group (CG) and the fixed effects of SEX (bull and heifer), AOD (2 to 11+ yr), and SEX by AOD interaction. In the least squares analysis, CG, SEX, and AOD were highly significant for WWT. The interaction of SEX by AOD was not significant. Estimates of AOD adjustment factors indicate that 2-, 3-, 4- and 11 +-yr-old dams are being overadjusted using BIF correction factors. Adjustments developed by this analysis more adequately fit the Senepol data.

Two experiments were conducted to evaluate differences in testicular, seminal and hematological characteristics in adapted (Senepol) and nonadapted (Holstein) Bos taurus bulls under the semi-arid environmental conditions of St. Croix, Virgin Islands (17 degrees N, 64 degrees W). In Experiment 1 mature, sexually-rested Senepol (n=10) and Holstein (n=9) bulls of similar age (37 months) and body weight (715 kg) and grazing on adjacent native pastures, were tested on the same day in July (28.8 degrees C mean ambient temperature, 81.5% humidity). Senepol bulls had lower (P0.01) rectal temperatures (39.3 vs 40.0 degrees C) and higher (P0.01) packed cell volumes (41.4 vs 35.2%) than Holstein bulls. Scrotal circumference was 3 cm larger (P0.1) and testis tone firmer (P0.001) in Senepol compared to Holstein bulls. Ejaculates, obtained by electroejaculation, contained 3.2x10(9) more spermatozoa with fewer abnormal tails and detached acrosomes in Senepol than in Holstein bulls (P0.05). In Experiment 2, Senepol (n=42) and Holstein (n=30) bulls, representing 3 beef and 5 dairy farms, were evaluated during the summer (August/September) and winter (February/March). Again, scrotal circumference was larger (P0.05) and testis tone firmer (P0.001) in Senepol than in Holstein bulls, with no effect of season. Seminal fructose was higher (P0.01) in Senepol than in Holstein bulls and decreased (P0.01) during the winter collection. Blood plasma urea nitrogen and glucose were similar between breeds, but urea nitrogen was lower (P0.01) during the summer. Significant (P0.01) breed-by-age interactions were observed for the frequency of spermatozoa with protoplasmic droplets, decreasing in Holstein but not in Senepol bulls. The data point to differences between the adapted and nonadapted breed type in testicular and ejaculate characteristics, but also suggest that season has only a limited impact on bull reproductive function under the environmental conditions in St. Croix.

The pattern of testicular and epididymal development of 93 Bos indicus cross bulls aged between 4 and 27 months was measured by means of semi-quantitative histology. In the testis, weight and seminiferous tubule diameter developed in a curvilinear fashion and the lumen formed during the period of rapid testicular growth. Epididymal development followed an ascending pattern, progressing from the cauda to the caput, and varied from curvilinear growth in the proximal regions to a more linear growth distally. After differentiation, mean tubular diameters, corrected for tissue shrinkage, were 207, 373, 353 and 405 μm for testis, caput, corpus and cauda, respectively, and epithelial heights were 66.9, 92.5 and 76.7 μm in caput, corpus and cauda, respectively. Contemporary Friesian bull calves had greater testicular and epididymal weights and tubular dimensions than Bos indicus cross bulls of similar age when compared on a liveweight basis. Despite a similar pattern of reproductive development in both strains, these results suggest a delayed and slower rate of sexual maturation in Bos indicus cross bulls.

Scrotal insulation for 48 h raised subcutaneous scrotal temperature by 4 degrees C in hybrid Bos indicus X Bos taurus bulls. The incidence of decapitated spermatozoa in the ejaculate increased significantly between 6 and 14 days and that of protoplasmic droplets and tail abnormalities between 20 and 23 days after insulation, respectively. Simultaneously, the percentages of spermatozoa with lost and damaged acrosomes increased significantly 12-17 days after insulation. At slaughter 23 days after scrotal insulation sperm production rates and gonadal reserves had not been affected by insulation, but epididymal reserves were markedly reduced, particularly in the cauda. Elevated testicular temperature therefore had an effect on immature spermatozoa in the caput epididymidis and on spermatids, but it is suggested that selective sperm resorption in the rete testis and excurrent ducts may prevent some of these changes being expressed in the ejaculate.

Reproductive development was monitored in 13 1 2 Brahman (BX), 20 3 4 BX, 8 1 2 Sahiwal (SX) and 11 3 4 SX crossbred bulls between one and two years of age. Liveweight increased during wet season (0.7 kg/day) and decreased during dry season conditions (-0.25 kg/day). Scrotal circumference (SC) increased from 18.6 to 25.0 cm, but decreased slightly during the later stages of the dry season. First ejaculates containing 50 x 10(6) spermatozoa were obtained from 25% of the bulls at 15.3 months of age and from 84% by two years of age. Sperm motility and morphology showed no consistent pattern, but number of sperm per ejaculate increased and seminal fructose concentrations decreased with advancing age. Significant genotype differences were noted for SC and seminal characteristics. Estimated age and liveweight at puberty were 570, 563, 578 and 542 days, and 251, 265, 247 and 256 kg for 1 2 BX, 3 4 BX, 1 2 SX and 3 4 SX bulls, respectively.

Ten mature Bos indicus cross bulls were unilaterally vasoligated and the scrotum was insulated for 48 hours in six of the animals (treated). Semen was collected at 2-day intervals by electroejaculation, until the reproductive tract was recovered at slaughter either 14, 20 or 26 days after treatment. Decapitate spermatozoa and spermatozoa with proto-plasmic droplets increased significantly (P < 0.01) over pre-treatment values at 12 to 16 and 16 to 20 days, respectively, after insulation. Vasoligation and scrotal insulation had no effect on testicular sperm reserves, but epididymal sperm reserves on the ligated side were significantly (P < 0.05) reduced in the caput and increased in corpus and cauda. Total numbers of spermatozoa recovered from the patent side (epididymal sperm reserves and ejaculatory sperm output) exceeded sperm reserves recovered from the ligated side at 20 (28.2 vs. 23.2 × 109) and 26 days (47.1 vs. 18.7 × 109) after treatment in the insulated bulls. The percentage of decapitate spermatozoa was higher and the proportion of spermatozoa with protoplasmic droplets was consistently lower in the ligated cauda epididymidis. These findings are discussed in relation to likely alterations in epididymal function following scrotal insulation.

Plasma LH and testosterone (T) concentrations were measured before (basal) and two hours after (peak) GnRH stimulation in 52 Bos indicus strain bulls between one and two years of age. The animals comprised 13 1 2 Brahman, 20 3 4 Brahman, 8 1 2 Sahiwal and 11 3 4 Sahiwal cross bulls and samples were collected at approximately seven week intervals. Basal- and peak-T concentrations increased between one and two years of age, and basal LH concentrations decreased; no changes in peak LH were noted over time. Peak-T concentrations were significantly correlated with scrotal circumference (SC), sperm per ejaculate and seminal fructose. Significant genotype differences were noted, Sahiwal cross bulls had higher peak-T concentrations at puberty than Brahman cross bulls.

Serum luteinizing hormone (LH) concentrations were measured at 4, 6, 8 and 10 mo of age in estradiol-17beta (E(2))-treated (n = 4) and contemporary control steers (n = 4). Serum LH was measured in samples collected at 30-min intervals starting at 0600 h for 12 h and for an additional 6 h following luteinizing hormone-releasing hormone (LHRH) injection. Estradiol-17beta suppressed mean serum LH concentrations at all ages (P0.01), but it suppressed pulsatile release of LH only at 4 and 6 mo (P0.01), not 8 and 10 mo of age. Luteinizing hormone release in response to LHRH, expressed as the area under the secretory curve, was larger and LH concentrations returned to pre-LHRH levels later in E(2)-treated steers (P0.01). Peak LH concentrations after LHRH varied with age (P0.05) but not E(2) treatment. These results suggest that E(2) suppression of LH in steers occurs at the hypothalamic level and developmental changes take place within the hypothalamicpituitary axis in absence of androgen feedback from the testis.

Testes and epididymides were collected from 136 young (1.5 to 3.5 years of age) and 33 mature Bos indicus strain bulls, reared under extensive range conditions in the tropics. Testicular and epididymal sperm reserves and weights increased at different rates in the young bulls. Daily sperm production per gram of testis (DSPG) increased significantly before and epididymal sperm reserves after 2.5 years of age. Testicular and epididymal weights increased linearly with bodyweight. Sahiwal cross bulls had higher testicular and epididymal weights, and greater sperm reserves than did Brahman cross bulls at the same age. Testicular and epididymal weights, daily sperm production and epididymal sperm reserves for mature Brahman bulls were 670g, 61g, 4.9 billion and 25.5 billion respectively. Testis weight was highly correlated with total daily sperm production (DSP) and epididymal weight.

Two experiments were conducted to examine the effects of repeated low-dose injections of gonadotropin releasing hormone (GnRH) 30 to 40 d post partum on reproductive characteristics in multiparous suckled Brahman cross cows. In Experiment I, 39 cows were injected (i.v.) with GnRH (5 mug/injection) at 2-h intervals for either 0 (control), 6, 12, or 24 h at 30 to 37 d post partum. GnRH injections for short periods (6h) increased the number of cows exibiting estrus within 45 d of treatment, but cows injected for 24 h failed to exhibit estrus during this period. The period from treatment to first estrus was shorter in the 6-h GnRH group compared to the control group. Injections for 6h significantly (P0.05) increased in serum luteinizing hormone (LH) concentrations 1 d after GnRH treatment. In Experiment II we examined the effect of i.v. GnRH injections (5 mug/injection at 2-h intervals) for 6h in a larger group of cows (n = 70). The days from treatment to first estrus were reduced (P0.05) in GnRH-treated cows; however, first-service conception rates were significantly lower (P0.01) in treated compared to control cows (46.4 and 80.0%, respectively). The results led us to believe that GnRH injections for short periods reduce postpartum interval to first estrus, but fertility at first estrus is lowered.