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The objective of this study was to evaluate the effect on the estimates of heritability and permanent environmental effects as a proportion of phenotypic variance for FAMACHA score, fecal worm egg count and hematocrit value when year-round records are used. Records from 1008 Dorper sheep in a private South African flock comprised 17,711 FAMACHA scores, 6837 fecal worm egg counts (FEC; practically only Haemonchus contortus ), and 4209 hematocrit (packed cell volume-PCV) values that were collected from 1997 to 2000. Animal models were used to conduct single-trait analyses. Data were analyzed in two sets: 1) warm season records only and 2) year-round records. Treatment (with anthelmintic) status was investigated as a 2-level fixed effect in both sets; additionally records of treated sheep were removed for another analysis of both data sets. In analyses of warm season records, estimates of heritability and permanent environmental variance as a proportion of phenotypic variance for FAMACHA score were 0.33 ± 0.03 and 0.04 ± 0.02, respectively, when treatment status was modeled, and 0.41 ± 0.02 and 0, respectively, when treated records were excluded from the analysis. Heritability estimates for PCV were 0.22 ± 0.06 (treatment status modeled) and 0.28 ± 0.07 (treated records excluded), while permanent environmental variance as a proportion of phenotypic variance was, respectively, 0.13 ± 0.05 and 0.09 ± 0.06. Fecal worm egg count heritability estimates were 0.10 ± 0.03 (treatment status modeled) and 0.13 ± 0.04 (untreated records only). Permanent environmental variance for FEC was 0.04 ± 0.03 when treated records were excluded and 0.05 ± 0.03 when treatment status was included in the analyses. In analyses of year-round records, estimates of heritability and permanent environmental variance as a proportion of phenotypic variance for FAMACHA score were 0.32 ± 0.03 and 0.03 ± 0.02, respectively (treatment status modeled) and 0.36 ± 0.03 and 0.02 ± 0.02 (treated records excluded). Packed cell volume heritability and permanent environmental variance were, respectively, 0.19 ± 0.05 and 0.18 ± 0.05 in the analyses of untreated records, and 0.18 ± 0.04 and 0.15 ± 0.04, when treatment status was modeled. Heritability estimates for FEC were the same (0.11) for untreated records only, and when treated records were included. Permanent environmental variance was 0.04 ± 0.02 (treated records included) and 0.03 ± 0.02 (treated records excluded) for FEC. Collection and inclusion of cool season (that is, outside of the regular worm proliferation season) records in analyses may not substantially change estimates of genetic parameters for these traits.

Despite strong economic opportunities and incentives for small ruminant production, their health and productivity are often severely affected by parasitic disease. To combat these effects, most farms administer anthelmintics to their animals at frequent intervals, and without consideration to principles of sustainable integrated parasite management (SIPM). This has led to growing problems caused by the development of drug-resistant populations of gastrointestinal nematodes (GIN) in much of the world, particularly in Haemonchus contortus . The objectives of this research were to characterize levels of anthelmintic resistance on small ruminant farms located in the mid-Atlantic US and to compare the fecal egg count reduction test (FECRT) and larval development assay (LDA) for detecting resistance. To achieve these objectives, the DrenchRite ® LDA was used to evaluate resistance status to benzimidazoles, ivermectin, moxidectin, and levamisole on 20 goat and 14 sheep farms in the Mid-Atlantic US over a 2-year period. A FECRT was also conducted on 14 of the same farms and on 2 additional farms in which the LDA was not completed. For the LDA and coprocultures, fecal samples were collected rectally from a minimum of 10 individual animals, pooled, and express-mailed to the University of Georgia for analysis. For the FECRT, albendazole, ivermectin, moxidectin, and/or levamisole were tested on each farm. Animals were allocated randomly based on FAMACHA © scores to 2–5 treatment groups, which included an untreated control group. The number of treatment groups on a farm depended on the number of qualified animals present. Haemonchus contortus was the most common parasite recovered from fecal cultures; the mean level across all farms was 79%. Results of the LDA indicated resistance to benzimidazoles, ivermectin, moxidectin, and levamisole on 100%, 82%, 47%, and 24% of farms, respectively. Multi-drug resistance to all 3 drug classes was detected for H. contortus on 18% of farms (1 sheep and 5 goat farms). Of the 16 farms tested by FECRT, resistance to albendazole was present on 8/10 farms, to ivermectin on 4/4 farms, to moxidectin on 7/9 farms and to levamisole on 2/5 farms tested. Results obtained from the FECRT and the LDA (p = 0.51) were similar. The prevalence of resistance found in this study in the mid-Atlantic region of the US is very similar to that reported in an earlier survey of resistance performed in the Southern US, demonstrating that anthelmintic resistance in GIN is a serious problem on small ruminant farms throughout the Eastern US.

In four experiments, 77 naturally-infected Boer crossbred kids and 28 artificially-inoculated Katahdin lambs were used to evaluate the effect of pumpkin seeds (Exp 1; 21 kids), ginger or pumpkin seed drench (Exp 2; 30 kids) and pumpkin seed oil (Exp 3 and 4: 28 lambs and 26 kids, respectively) on gastrointestinal nematode (GIN) indicators. In all experiments, kids and lambs were placed in individual pens and received pre-weighed rations of a commercially pelleted meat goat or sheep diet daily. In Exp 1, kids were supplemented with ground pumpkin seeds (PUM; n = 10) mixed into feed daily at a rate of 5 g/kg body weight (BW) or were not supplemented (CON; n = 11) for 21 days. In Exp 2, kids were orally drenched with water (CON; n = 10), 5 g pumpkin seed/kg BW (PUM; n = 10) or 3 g ginger/kg BW (GIR; n = 10) every other day for 42 days. In Exp 3, lambs were orally drenched with 2 ml/kg water (CON; n = 7), 2.0 ml/kg BW pumpkin seed oil once every 7 days (PUM1; n = 10), or 2.0 ml/kg BW pumpkin seed oil daily for 3 out of every 7 days (PUM2; n = 11) for 28 days. In Exp 4, kids were orally drenched with 2 ml/kg water (CON; n = 13), or 2.0 ml/kg BW pumpkin seed oil (PUM; n = 13) every other day for 35 days. In all experiments, BW, daily feed intake and blood and fecal samples were collected every 7 days. All animals in Exp 2 were harvested at a USDA-inspected abattoir and abomasal and small intestinal contents were collected for total worm counts. The FEC were similar for treatments in all experiments. Treatment influenced PCV ( P 0.05) only in Exp 1 and 4. In Exp 2, at harvest, there was a tendency ( P = 0.08) for CON animals to have a higher number of total GIN than GIR-treated animals, but PUM-treated animals were intermediate. BW were similar for treatments in Exp 1, 2 and 3 while CON animals in Exp 4 had a greater BW than PUM-treated animals on day 7 only and were similar thereafter (treatment by day interaction, P 0.05). In these studies, pumpkin and ginger treatments administered were not effective in reducing FEC in meat goat kids or lambs.

Our objective was to determine whether breed differences existed in response to exposure and treatment of virulent foot rot. Dorset (DS), 1/2 Dorper (DX), 3/4 or greater Dorper (DO), Gulf Coast Native (GC), Katahdin (KA), and St. Croix (SC) mature sheep and lambs were exposed to virulent foot rot in spring 2003. Treatment for foot rot was initiated in 132 lambs and 262 mature sheep in late July. There were eight pasture groups treated, two of which were minimally exposed to foot rot. Treatment included hoof paring, foot bathing with 10% zinc sulfate with surfactant, allowing the zinc sulfate to dry on the foot and moving to a small paddock that had not been exposed to small ruminants for more than 14 d. Foot bathing was repeated every 7 d for a maximum of five treatments. Animals that had not responded (odor or any indication of persistent infection) by then were culled from the flock. As an indication of severity of foot rot for each animal, the number of areas on the foot (interdigital and two digits for each foot), a foot score (0 = no infection found; 1 = infection of digits only; 2 = infection of interdigital area and could include digits), and presence of characteristic odor was recorded. Least squares means for number of areas infected were greater for mature than growing sheep (2.07 ± 0.16 versus 0.88 ± 0.31; P P P P P P P P

The objective of the present study was to compare live animal performance and carcass characteristics of 3/4 or 7/8 Dorper (DO; n = 30), purebred Katahdin (KA; n = 20), purebred St. Croix (SC; n = 17) and purebred Suffolk (SU; n = 10) lambs born in the spring and fall of 2001. After weaning, lambs were supplemented with up to 680 g of a corn-soybean meal supplement while grazing bermudagrass pastures overseeded with ryegrass. Lambs were slaughtered at approximately 210 d of age. From birth to weaning, DO lambs gained faster (P < 0.001) than KA or SC lambs, whereas KA lambs had higher (P < 0.001) ADG than SC lambs. Additionally, DO and SU wethers had greater (P < 0.02) ADG from weaning to slaughter than SC or KA wethers. Suffolk lambs were heavier (P < 0.001) at slaughter and produced heavier (P < 0.001) carcasses than lambs from hair-sheep breeds. Carcasses of KA lambs were fatter (actual fat thickness; P < 0.02) resulting in higher yield grades (P < 0.03) than carcasses of DO, SC, or SU lambs. Carcasses of DO and SU had larger (P < 0.001) longissimus muscle (LM) areas than those of KA or SC carcasses, whereas kidney fat weight and percentage were greater (P < 0.001) in carcasses from KA and SC than DO and SU lambs. Lean maturity was similar (P = 0.32) among breed-types. However, skeletal maturity was greater (P < 0.001) in SU than hair-sheep carcasses. Flank-streaking scores were similar (P = 0.19) among the breed-types, but conformation scores were higher (P < 0.001) for DO and SU carcasses and resulted in higher (P < 0.001) quality grades than SC carcasses. The LM of SU lambs was lighter (higher L* values; P < 0.05) than that of KA and SC lambs, whereas the LM from DO lambs was redder (higher a* values; P < 0.001) than SC and SU and more (P < 0.001) yellow than that of the other breed-types. Chops from SU lambs were tougher (higher shear force values; P < 0.007) than chops from the hair-sheep breeds. Results of this study indicate that ADG, carcass muscularity and meat quality were similar between DO and SU lambs, and, although fatter, carcass muscularity of KA was similar to that of DO lambs.

Our objective was to determine the influence of short-term exposure to endophyte-infected tall fescue on reproductive function of ram lambs. Rams (214 days of age) were fed a diet free of endophyte-infected fescue seed (EF; n = 8) or endophyte-infected fescue seed (EI; n = 9; 34% of diet; 4.8 μg g −1 ergovaline) for 6 weeks. Feed offered to EF rams, individually fed, was reduced to the average intake of EI lambs from previous day so that intake was similar between treatments and averaged 2.4% BW (DM basis), leading to daily intake of 33.7 μg ergovaline kg −1 BW for the EI fed lambs. Daily high ambient temperature for the trial ranged between 16 and 26 °C. Respiration rate and rectal temperature were measured at 14:00 daily. Blood was collected for serum concentrations of prolactin (weekly) and testosterone (twice weekly). Body weight and body condition scores (BCS; 1 = thin; 5 = fat) were determined every 14 days. Scrotal circumference, scrotal skin temperature, and semen characteristics were determined weekly. Rams were slaughtered after 6 weeks of feeding. Signs of fescue toxicosis in EI fed rams included increased rectal temperature ( P R 2 = 0.11) and respiration rate (day, P R 2 = 0.25) when high ambient temperature exceeded 22 °C and reduced serum concentrations of prolactin (diet × day, P P P R 2 = 0.08). Scrotal skin temperature, scrotal circumference, semen volume, percent sperm motility, and percent abnormal sperm were similar between treatments. Spermatozoa concentration tended to be greater in EF compared with EI fed rams after 43 days of feeding ( P R 2 = 0.15). Rate of forward movement of spermatozoa tended to increase at a greater rate between Days 8 and 29 in EF compared with EI fed rams (diet × day, P

A study was conducted to evaluate the relative resistance to a natural or induced gastrointestinal (GI) nematode infection in hair and wool breeds of lambs. In Experiment 1, natural GI nematode infection was evaluated among fall born Dorper crossbred (DO; n = 17) or St. Croix (SC; n = 17) lambs. Ewe and wether lambs were weaned at 84 ± 1.1 days of age and dewormed. Fecal egg counts (FECs) and blood packed cell volume (PCV) were determined between weaning and 56 days later. In Experiment 2, natural GI nematode infection was evaluated among spring born DO (7/8 or 3/4 Dorper; n = 24), Katahdin (KA; n = 26), SC (n = 8), and Suffolk (SU; n = 10; wethers only) ewe and wether lambs from weaning (60 ± 1.3 days of age; April) to 115 ± 1.3 days of age (June). In both studies, lambs grazed bermudagrass overseeded with ryegrass, previously grazed with sheep, and were supplemented with 225–500 g of corn/soybean meal supplement. In Experiment 3, the relative resistance was examined among DO (n = 8), KA (n = 8), and SC (n = 9) ewe lambs to induced GI nematode infection (20,000 Haemonchus contortusL3). Lambs were weaned at 62 ± 2.3 days of age, dewormed 22 days later and inoculated 6 days later (Day 0). In Experiment 1, FEC was greater ( P< 0.04) at weaning in DO lambs and PCV was similar between DO and SC lambs. In Experiment 2, FEC was greatest and PCV least in DO lambs when compared with other breeds (breed × time, P< 0.003). In Experiment 3, FEC was greater in DO and KA lambs compared with SC lambs ( P< 0.02). By Day 42, four DO, six KA, and three SC lambs had been dewormed. With a low to moderate challenge, resistance to infection was similar among the three hair breeds examined and greater than the wool breed lambs. When the challenge escalated, St. Croix lambs were most resistant and Dorper crossbred lambs were similar or less resistant than Katahdin lambs. Published by Elsevier B.V.

The objective of these studies was to evaluate the seasonal maintenance of body weight (BW) and condition, signs of fescue toxicosis, and reproductive performance of straightbred and cross-bred hair sheep grazing tall fescue or bermudagrass forage. Breeds examined were St. Croix (SC), Romanov (ROM) and cross-bred ewes. BW was measured in the summer (1998–2000) and the fall (1999) on ewes grazing bermudagrass overseeded with ryegrass (BER) or tall fescue (FES) forage. Body condition score (BCS) and serum prolactin concentrations were determined in the summer (1999, 2000) and fall (1999). Pregnancy and lambing rates of a summer and fall (1999) breeding season and pregnancy rates of the spring (2000) breeding season were recorded. BW and BCS reflected seasonal differences related to the forage availability of BER and FES, seasonal variations in toxins of FES forage and breed differences. At all times, serum prolactin concentrations were reduced in ewes grazing FES pastures (P

The objective of three experiments was to determine the influence of high condensed tannin (CT) grain sorghum on gastrointestinal parasite fecal egg counts (FEC). Sixteen naturally infected Boer crossbred mixed-sex goats were used. Animals that were supplemented with grain daily were removed from pasture and placed in individual pens and fed treatment diets for 21 or 14 days (Experiment 3). Goats were allowed ad libitum access to water and diets containing high or low CT cracked grain sorghum. On day 0 and every 7 days thereafter, PCV, FEC and FAMACHA ® eyelid color scores (EYE; Experiment 1 only) were recorded. For Experiment 1, percentage of animals dewormed, PCV and EYE were not influenced by treatment and averaged 13.6 ± 4.5% per treatment period, 23.4 ± 0.8% and 3.2 ± 0.12, respectively, for all animals. The FEC increased after day 0 for control but not high tannin grain sorghum fed goats (treatment by day interaction, P r = −0.45; P P