Higher whole-blood selenium is associated with improved immune responses in footrot-affected sheep

ABSTRACT: We reported previously that sheep affected with footrot (FR) have lower whole-blood selenium (WB-Se) concentrations and that parenteral Se-supplementation in conjunction with routine control practices accelerates recovery from FR. The purpose of this follow-up study was to investigate the mechanisms by which Se facilitates recovery from FR. Sheep affected with FR (n = 38) were injected monthly for 15 months with either 5 mg Se (FR-Se) or saline (FR-Sal), whereas 19 healthy sheep received no treatment. Adaptive immune function was evaluated after 3 months of Se supplementation by immunizing all sheep with a novel protein, keyhole limpet hemocyanin (KLH). The antibody titer and delayed-type hypersensitivity (DTH) skin test to KLH were used to assess humoral immunity and cell-mediated immunity, respectively. Innate immunity was evaluated after 3 months of Se supplementation by measuring intradermal responses to histamine 30 min after injection compared to KLH and saline, and after 15 months of Se supplementation by isolating neutrophils and measuring their bacterial killing ability and relative abundance of mRNA for genes associated with neutrophil migration. Compared to healthy sheep, immune responses to a novel protein were suppressed in FR-affected sheep with smaller decreases in FR-affected sheep that received Se or had WB-Se concentrations above 250 ng/mL at the time of the immune assays. Neutrophil function was suppressed in FR-affected sheep, but was not changed by Se supplementation or WB-Se status. Sheep FR is associated with depressed immune responses to a novel protein, which may be partly restored by improving WB-Se status (> 250 ng/mL).     

Intramuscular Selenium Administration in Selenium-Deficient Cattle

Nine recently weaned Hereford heifers were randomly assigned to a control group (n = 3) or a treatment group (n = 6). The animals were selenium (Se) deficient (mean ± SD blood Se concentration = 0.024 ± 0.012 μg/mL). They were maintained on a selenium-deficient diet, and on day 0 of the study the treatment group was given 0.05 mg Se/kg body weight intramuscularly, while the control group received a placebo. The Se concentration of blood, serum, and urine as well as the glutathione peroxidase (GSH-Px) activity of blood and serum was measured over an 84-day period. Peak blood Se and serum Se concentrations (mean ± SD) in the treatment group occurred at 5 hours postinjection and were 0.131 ± 0.028 μg/mL and 0.154 ± 0.027 μg/mL, respectively. The mean blood Se concentration of the treatment group was greater (P < .05) than that of the control group for the first 28 days after injection. The mean serum Se concentration of the treatment group was greater (P < .05) than that of the control group for all times after injection, except for day 56. The mean (±SD) blood GSH-Px activity of the treatment group (12.0 ± 2.3 mU/min/mg hemoglobin) was increased (P < .05) over the control group (2.0 ± 1.4 mU/min/ mg hemoglobin) by day 28 and continued to be greater (P < .05) throughout the 84 day postinjection period. The blood GSH-Px activity and the blood Se concentrations in the treatment group heifers did not reach concentrations considered indicative of Se adequacy (30 mU/min/mg hemoglobin and 0.10 μg/mL, respectively) except briefly, at 5 hours postinjection when the blood Se concentration of the treatment group was 0.131 ± 0.028 μg/mL. The mean serum GSH-Px activity of the treatment group did not differ at any time from that of the control group (P≥ .17). The mean (±SD) fractional excretion (FE) of Se, as an estimate of Se excretion, was greater (P < .05) in the treatment group heifers (n = 5; 6.2 ± 2.5%) than in the control heifers (n = 3; 1.3 ± 0.6%) at 24 hours postinjection. The mean (±SD) weight gain, from day 0 to day 84, for the treatment group heifers was 63.0 ± 18.1 kg and the mean weight gain for the control group heifers was 53.1 ± 7.3 kg at 84 days postinjection and there was no difference between the groups (P < .39). Conclusions drawn from this study include: 1) the increase in blood GSH-Px activity occurs approximately 28 days after Se injection given to Se-deficient heifers, 2) a single label dose of injectable Se does not result in blood Se concentrations or blood GSH-Px activity normally considered to be adequate, 3) the label dose of injectable Se, although therapeutically beneficial for nutritional myodegeneration (NMD), does not seem to be a desired method for long-term Se supplementation of cattle consuming a Se-deficient diet, and 4) blood Se is a better predictor of Se status than serum Se. (Journal of Veterinary Internal Medicine 1993; 7:342–348. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Randomized Clinical Trial of Long‐Acting Oxytetracycline,Foot Trimming,and Flunixine Meglumine on Time to Recovery in Sheep with Footrot

Background: Internationally, foot trimming is used by most farmers, and parenteral antibacterials by some, to treat sheep with footrot. Nonsteroidal anti‐inflammatory drugs (NSAID) are sometimes used. No clinical trials have compared these treatments. Objectives: To investigate the above treatments on time to recovery from lameness and foot lesions in sheep with footrot. Animals: Fifty‐three sheep with footrot on a commercial farm in England. Methods: In a randomized factorial design, the sheep were allocated to 6 treatment groups. The treatments were oxytetracycline spray to all sheep (positive control) and one or more of parenteral administration of long‐acting oxytetracycline, flunixine meglumine, and foot trimming on day 1 or 6 of diagnosis. Follow‐up was for 15 days. Time to recovery from lameness and lesions was investigated with discrete‐time survival models. Results: There was significant association (P < .05) between recovery from lameness and lesions. Sheep receiving antibacterials parenterally recovered faster from lameness (odds ratio [OR]: 4.92 [1.20–20.10]) and lesions (OR: 5.11 [1.16–22.4]) than positive controls, whereas sheep foot trimmed on day 1 (lameness—OR: 0.05 [0.005–0.51]; lesions—OR: 0.06 [0.008–0.45]) or day 6 of diagnosis (lameness—OR: 0.07 [0.01–0.72]; lesions—OR: 0.07 [0.01–0.56]) recovered more slowly than positive controls. NSAID had no significant effect on recovery. Conclusions and Clinical Importance: If foot trimming on day 1 or 6 of diagnosis was stopped and parenteral antibacterials were used, then over 1 million sheep/annum lame with footrot in the United Kingdom would recover more rapidly with benefits to productivity. Globally, this figure would be much higher.     

Serum pharmacokinetics of oxytetracycline in sheep and calves and tissue residues in sheep following a single intramuscular injection of a long-acting preparation

The pharmacokinetics of a long‐acting oxytetracycline (OTC) formulation (Liquamycin® LA‐200®) injected intramuscularly (i.m.) at a dose of 20 mg/kg were determined in four calves and 24 sheep to determine if the approved label dose for cattle provided a similar serum time/concentration profile in sheep. The AUC for the calves was 168±14.6 (μg ? h/mL) and was significantly less than the AUC for sheep (209±43 μg ? h/mL). Using the standard two‐stage approach and a one‐compartment model, the mean Cmax for the calves was 5.2±0.8 μg/mL, and for the sheep was 6.1±1.3 μg/mL. The mean terminal phase rate constants were 0.031 and 0.033 h, and the Vdss were 3.3 and 3.08 L/kg for the calves and sheep respectively. Analysis of the data using the standard two‐stage approach, the naive pooled‐data approach and a population model gave very similar results for both the cattle and sheep data. Sheep tissue residues of OTC in serum, liver, kidney, fat, muscle and injection site were measured at 1, 2, 3, 5, 7 and 14 days after a single i.m. injection of 20 mg/kg OTC. Half‐lives of OTC residues in the tissues were 38.6, 33.4, 28.6, 25.4, 21.3, and 19.9 h for injection site, kidney, muscle, liver, mesenteric fat and renal fat, respectively. The ratio of tissue to serum concentration was fairly consistent at all slaughter times, except for the fat and injection sites. The mean ratios were 1.72, 4.19, 0.11, 0.061, 0.84 and 827 for the liver, kidney, renal fat, mesenteric fat, muscle and injection sites, respectively. The tissue concentrations of OTC residues were below the established cattle tolerances for OTC in liver (6 p.p.m.), muscle (2 p.p.m.) and kidney (12 p.p.m.) by 48 h, and in injection site muscle by 14 days after the single i.m. injection of 20 mg/kg.     

Hormonal and metabolic relation to restraint and human handling in growing-fattening steer

Endogenous relationship to restraint and human handling were studied with growing–fattening steers. Thirty‐five crossbred (Japanese Black × Holstein) steers aged 6–10 months were randomly assigned to three pens. They had free access to an Italian ryegrass hay and a restricted amount of high‐concentrate diets (total digestible nutrients (TDN) 70.5%, digestible crude protein (DCP) 10.0%) for the first 6 months of trial. Then they had free access to an oat hay and another vitamin A‐restricted diet (TDN 72.0%, DCP 10.0%) until slaughter. The steers were individually driven into a restraint stall, and bodyweight was recorded. Blood samples were then collected under haltered conditions. These serial handling procedures started at 2 h after the morning feeding were conducted in months 1, 3, 5 (growing stage, GS) and in months 7, 9, 11 (fattening stage, FS) of the trial. Mean peripheral blood concentrations of epinephrine (A; GS, 117.4 ± 76.4 pg/mL; FS, 64.1 ± 34.2 pg/mL), norepinephrine (NA; GS, 257.7 ± 95.0 pg/mL; FS, 125.9 ± 44.1 pg/mL), cortisol (GS, 1.6 ± 0.8 µg/dL; FS, 1.2 ± 0.4 µg/dL), glucose (GS, 83.1 ± 7.5 mg/dL; FS, 71.9 ± 6.9 mg/dL), non‐esterified fatty acid (NEFA; GS, 0.13 ± 0.06 mEQ/L; FS, 0.10 ± 0.06 mEQ/L) and vitamin A (GS, 90.5 ± 24.6 IU/dL; FS, 37.2 ± 21.3 IU/dL) were higher (all P < 0.01) in the GS than in the FS, whereas those of insulin (GS, 1.06 ± 0.82 µU/mL; FS, 1.36 ± 0.61 µU/mL) and leptin (GS, 4.5 ± 1.8 ng/mL human equivalent (HE); FS, 6.8 ± 2.4 ng/mL HE) were lower (both P < 0.01). The metabolite that correlated with A and NA was glucose (A: r = 0.61, P < 0.001; NA: r = 0.53, P < 0.01) in the GS, and the metabolites correlating with A, NA and cortisol were NEFA (A: r = 0.31, P < 0.10; NA: r = 0.32, P < 0.10; cortisol: r = 0.41, P < 0.05) and triglyceride (A: r = ?0.37, P < 0.05; NA: r = ?0.39, P < 0.05) in the FS. Vitamin A was a mediator between A (r = ?0.38, P < 0.05) and NA (r = ?0.42, P < 0.05) and insulin (r = 0.31, P < 0.10) in the GS, and between NA (r = ?0.33, P < 0.10) and leptin (r = 0.38, P < 0.05) in the FS. In conclusion, when changing from the growing to the fattening stages, the stress of handling and restraint had caused the pathways to shift from carbohydrate metabolism to lipid metabolism. In addition, vitamin A seemed to be an important mediator in the endogenous pathways in both stages.     

Effect in sheep of dietary concentrate content on secretion of growth hormone, insulin and insulin-like growth factor-I after feeding

This study was designed to examine the effects of the proportion of concentrate in the diet on the secretion of growth hormone (GH), insulin and insulin‐like growth factor‐I (IGF‐I) secretion and the GH‐releasing hormone (GHRH)‐induced GH response in adult sheep fed once daily. Dietary treatments were roughage and concentrate at ratios of 100:0 (0% concentrate diet), 60:40 (40% concentrate diet), and 20:80 (80% concentrate diet) on a dry matter basis. Mean plasma concentrations of GH before daily feeding (10.00–14.00 hours) were 11.4 ± 0.4, 10.1 ± 0.5 and 7.5 ± 0.3 ng/mL on the 0, 40 and 80% concentrate diet treatments, respectively. A significant decrease in plasma GH concentration was observed after daily feeding of any of the dietary treatments and these decreased levels were maintained for 8 h (0%), 12 h (40%) and 12 h (80%), respectively (P < 0.05). Plasma IGF‐I concentrations were significantly decreased 8–12 h and 4–16 h after the end of feeding compared with the prefeeding level in the 40 and 80% concentrate diet treatments, respectively (P < 0.05). GHRH injection brought an abrupt increase in the plasma GH concentrations, reaching a peak 10 min after each injection, but, after the meal, the peak plasma GH values for animals fed 40% (P < 0.05) and 80% (P < 0.01) concentrate diet were lower than that for roughage fed animals. The concentrate content of a diet affects the anterior pituitary function of sheep resulting in reduced baseline concentrations of GH and prolonged GH reduction after feeding once daily.     

Pharmacokinetics of a controlled‐release liposome‐encapsulated hydromorphone administered to healthy dogs

The purpose of the study was to assess the pharmacokinetics of liposome‐encapsulated (DPPC‐C) hydromorphone administered intravenously (IV) or subcutaneously (SC) to dogs. A total of eight healthy Beagles aged 12.13 ± 1.2 months and weighing 11.72 ± 1.10 kg were used. Dogs randomly received liposome encapsulated hydromorphone, 0.5 mg/kg IV (n = 6), 1.0 mg/kg (n = 6), 2.0 mg/kg (n = 6), or 3.0 mg/kg (n = 7) SC with a 14–28 day washout between trials. Blood was sampled at serial intervals after drug administration. Serum hydromorphone concentrations were measured using liquid chromatography with mass spectrometry. Serum concentrations of hydromorphone decreased rapidly after IV administration of the DPPC‐C formulation (half‐life = 0.52 h, volume of distribution = 12.47 L/kg, serum clearance = 128.97 mL/min/kg). The half‐life of hydromorphone after SC administration of DPPC‐C formulation at 1.0, 2.0, and 3.0 mg/kg was 5.22, 31.48, and 24.05 h, respectively. The maximum serum concentration normalized for dose (C_MAX/D) ranged between 19.41–24.96 ng/mL occurring at 0.18–0.27 h. Serum hydromorphone concentrations fluctuated around 4.0 ng/mL from 6–72 h after 2.0 mg/kg and mean concentrations remained above 4 ng/mL for 96 h after 3.0 mg/kg DPPC‐C hydromorphone. Liposome‐encapsulated hydromorphone (DPPC‐C) administered SC to healthy dogs provided a sustained duration of serum hydromorphone concentrations.     

Effects of selenium supplementation on plasma progesterone concentrations in pregnant heifers

It is known that selenium (Se) has various functions in animals. Many investigations on the biochemical and physiological effects of Se have been previously reported; however, the detailed function of Se in reproduction is not yet clear. We proposed the possibility that Se plays a notable role in progesterone production. The aim of this study was to clarify the effects of Se supplementation on progesterone levels of pregnant Holstein heifers. Eight Holstein heifers (?Se) were fed basal diet (containing 0.022 ppm of Se) throughout the experiment. While a 0.3 ppm diet of Se (sodium selenite) was fed to another seven animals (+Se) with basal diet. Blood sampling was carried out every week. Plasma Se concentrations were higher in Se‐supplemented cows compared with controls (?Se) (P < 0.01) throughout the experiment. Se supplementation increased plasma progesterone in the 29–39 weeks of pregnancy from 4.98 ± 0.64 to 6.86 ± 0.49 ng/mL on average (P < 0.05). The present findings suggest that Se contributes to maintaining the function of the corpus luteum and/or placenta in the latter period of pregnancy.     

Pharmacokinetics of an extended‐release formulation of eprinomectin in healthy adult alpacas and its use in alpacas confirmed with mange

The study objective was to determine the pharmacokinetics and clinical effects of an extended‐release 5% eprinomectin formulation (Longrange^®) following subcutaneous (s.c.) injection in healthy (n = 6) and mange‐infected (n = 4) adult alpacas. High‐performance liquid chromatography was used to analyze plasma samples obtained at regular intervals for 161 days following a single 5 mg/kg injection s.c. in healthy alpacas, and for 5 days following each dose (3 treatments, 2 months apart) in mange‐affected animals. Skin scrapings and biopsies were performed pre‐ and post‐treatment at two comparable sites in alpacas with mange. Four alpacas served as healthy controls. Eprinomectin plasma concentrations showed a biphasic peak (C_MAX‐1: 5.72 ± 3.25 ng/mL; C_MAX‐2: 6.06 ± 2.47 ng/mL) in all animals at 3.88 ± 5.16 days and 77 ± 12.52 days, respectively. Eprinomectin plasma concentrations remained above 1.27 ± 0.96 ng/mL for up to 120 days. Hematocrit (35.8 vs. 31.3%, P < 0.003) and albumin (3.5 vs. 2.8 g/dL P < 0.006) reduced significantly over 6 months in multidose animals, while fecal egg counts did not differ between groups. Self‐limiting injection site reactions occurred in 9 of 10 animals. Pre‐ and post‐treatment skin biopsies showed reduced hyperkeratosis, but increased fibrosis, with 1 of 4 alpacas remaining positive on skin scraping for mange. In conclusion, alpacas require a higher eprinomectin dose (5.0 mg/kg s.c.) than cattle, to reach comparable plasma concentrations.     

Sexual maturity,seasonal estrus,and gestation in female Indo-Pacific bottlenose dolphins Tursiops aduncus inferred from serum reproductive hormones

Reproductive hormones in serum concentrations of progesterone, estradiol, and testosterone in female Indo-Pacific bottlenose dolphins (Tursiops aduncus, n = 12) housed in Ocean Park Hong Kong were investigated in the present study. Results showed that, onset of puberty of captive Indo-Pacific bottlenose dolphins was at 5 years while sexual maturity was at 6. Average serum progesterone concentrations in non-pregnant sexually mature individuals was 0.33 (0.25–0.97) ng/mL (interquartile), significantly higher than in immature ones 0.26 (0.25–0.38) ng/mL. This study found significant difference in serum estradiol concentrations between individuals at the onset of puberty (9.5 ± 1.7 pg/mL, ±SD) and not (below detection limit 9 pg/mL). A slightly seasonal breeding pattern, with progesterone values tend to be higher from February to October (0.38 [0.25–1.07] ng/mL) was inferred. During pregnancy, serum progesterone concentrations range from 10.54 ± 8.74 ng/mL (indexed month post-conception [IMPC] 0) to 25.49 ± 12.06 ng/mL (IMPC 2), and display a bimodal pattern with 2 peaks in early- (25.49 ± 12.06 ng/mL, IMPC 2) and late-pregnancy (21.71 ± 10.25 ng/mL, IMPC 12), respectively. Serum estradiol concentrations can seldom be detected in early-pregnancy and increase constantly in mid- (9.45 ± 1.83 pg/mL) and late-pregnancy (11.88 ± 3.81 pg/mL), with a spike (15.45 ± 6.78 pg/mL) 1 month prior to delivery. Serum testosterone concentrations elevate significantly in IMPC 7 (0.36 ± 0.10 ng/mL) compared to other months (0.16 ± 0.10 ng/mL) of the year. The present study provides normal concentration profiles for some reproductive hormones in female Indo-Pacific bottlenose dolphins and can contribute to the breeding monitoring of this species. Also, our study would shed further light on the reproductive physiology of small cetaceans.     

Organic and inorganic selenium: I. Oral bioavailability in ewes

Although the essentiality of dietary Se for sheep has been known for decades, the chemical source and Se dosage for optimal health remain unclear. In the United States, the Food and Drug Administration (FDA) regulates Se supplementation, regardless of the source of Se, at 0.3 mg of Se/kg of diet (as fed), which is equivalent to 0.7 mg of Se/d or 4.9 mg of Se/wk per sheep. The objectives of this study were to evaluate the effects of Se source (inorganic vs. organic) and supplementation rate (FDA vs. supranutritional rates of 14.7 and 24.5 mg of Se/wk) on whole-blood (WB) and serum-Se concentrations. Mature ewes (n = 240) were randomly assigned to 8 treatment groups (n = 30 each) based on Se supplementation rate (4.9, 14.7, and 24.5 mg of Se?wk(-1)?sheep(-1)) and source [Na-selenite, Na-selenate (4.9 mg/wk only), and organic Se-yeast] with a no-Se control group (0 mg of Se/wk). Treatment groups were balanced for healthy and footrot-affected ewes. For 1 yr, ewes were individually dosed once weekly with 0, 4.9, 14.7, or 24.5 mg of Se, quantities equivalent to their summed daily supplementation rates. Serum- and WB-Se concentrations were measured every 3 mo in all ewes; additionally, WB-Se concentrations were measured once monthly in one-half of the ewes receiving 0 or 4.9 mg of Se/wk. Ewes receiving no Se showed a 78.8 and 58.8% decrease (P < 0.001) in WB- (250 to 53 ng/mL) and serum- (97 to 40 ng/mL) Se concentrations, respectively, over the duration of the study. Whole-blood Se decreased primarily during pregnancy (-57%; 258 to 111 ng/mL) and again during peak lactation (-44%; 109 to 61 ng/mL; P < 0.001). At 4.9 mg of Se/wk, Se-yeast (364 ng/mL, final Se concentration) was more effective than Na-selenite (269 ng/mL) at increasing WB-Se concentrations (P < 0.001). Supranutritional Se-yeast dosages increased WB-Se concentrations in a dose-dependent manner (563 ng/mL, 14.7 mg of Se/wk; 748 ng/mL, 24.5 mg of Se/wk; P < 0.001), whereas WB-Se concentrations were not different for the Na-selenite groups (350 ng/mL, 14.7 mg of Se/wk; 363 ng/mL, 24.5 mg of Se/wk) or the 4.9 mg of Se/wk Se-yeast group (364 ng/mL). In summary, the dose range whereby Se supplementation increased blood Se concentrations was more limited for inorganic Na-selenite than for organic Se-yeast. The smallest rate (FDA-recommended quantity) of organic Se supplementation was equally effective as supranutritional rates of Na-selenite supplementation in increasing WB-Se concentrations, demonstrating the greater oral bioavailability of organic Se.     

Pharmacokinetics of florfenicol after intravenous administration in Escherichia coli lipopolysaccharide‐induced endotoxaemic sheep

Experiments in different animal species have shown that febrile conditions, induced by Escherichia coli lipopolysaccharide (LPS), may alter the pharmacokinetic properties of drugs. The objective was to study the effects of a LPS‐induced acute‐phase response (APR) model on plasma pharmacokinetics of florfenicol (FFC) after its intravenous administration in sheep. Six adult clinically healthy Suffolk Down sheep, 8 months old and 35.5 ± 2.2 kg in body weight (bw), were distributed through a crossover factorial 2 × 2 design, with 4 weeks of washout. Pairs of sheep similar in body weight were assigned to experimental groups: Group 1 (LPS) was treated with three intravenous doses of 1 μg/kg bw of E. coli LPS before FFC treatment. Group 2 (control) was treated with an equivalent volume of saline solution (SS) at similar intervals as LPS. At 24 h after the first injection of LPS or SS, an intravenous bolus of 20 mg/kg bw of FFC was administered. Blood samples (5 mL) were collected before drug administration and at different times between 0.05 and 48.0 h after treatment. FFC plasma concentrations were determined by liquid chromatography. A noncompartmental pharmacokinetic model was used for data analysis, and data were compared using a Mann–Whitney U‐test. The mean values of AUC_0–∞ in the endotoxaemic sheep (105.9 ± 14.3 μg·h/mL) were significantly higher (P < 0.05) than values observed in healthy sheep (78.4 ± 5.2 μg·h/mL). The total mean plasma clearance (CL_T) decreased from 257.7 ± 16.9 mL·h/kg in the control group to 198.2 ± 24.1 mL·h/kg in LPS‐treated sheep. A significant increase (P < 0.05) in the terminal half‐life was observed in the endotoxaemic sheep (16.9 ± 3.8 h) compared to the values observed in healthy sheep (10.4 ± 3.2 h). In conclusion, the APR induced by the intravenous administration of E. coli LPS in sheep produces higher plasma concentrations of FFC due to a decrease in the total body clearance of the drug.     

Impact of footrot vaccination and antibiotic therapy on footrot and contagious ovine digital dermatitis

Footrot and contagious ovine digital dermatitis (CODD) are common causes of foot disease of sheep in the UK. The study reported here is a split flock randomised treatment trial undertaken on a group of 748 fattening lambs on a UK sheep farm affected by CODD and footrot. The sheep were randomly assigned to one of two treatment protocols. In protocol A, all sheep were given two doses of footrot vaccine (Footvax, MSD), plus targeted antibiotic therapy (long-acting amoxicillin, Betamox LA, Norbrook Pharmaceuticals) to sheep with foot lesions likely to be associated with a bacterial infection. In protocol B, the sheep only received targeted antibiotic therapy. Sheep were re-examined and foot lesions recorded five and nine weeks later. New infection rates in the footrot vaccinated group were lower compared with the vaccinated group for both CODD (18.2 per cent compared with 26.4 per cent, P=0.014) and footrot (12.55 per cent compared with 27.5 per cent, P<0.001). Recovery rates were unaffected for CODD (80.46 per cent compared with 70.97 per cent, P=0.14) but higher for footrot (92.09 per cent compared with 81.54 per cent, P=0.005) in sheep which received the vaccine. On this farm, a footrot vaccine efficacy of 62 per cent was identified against footrot and 32 per cent against CODD infection. An association between a sheep having footrot at visit 1 and subsequently acquiring CODD was identified (odds ratio [OR] 3.83, 95 per cent CI 2.61 to 5.62, P<0.001). These results suggest a role for infection with Dichelobacter nodosus in the aetiopathogenesis of CODD on this farm.     

Leptin and ghrelin levels in colostrum,milk and blood plasma of sows and pig neonates during the first week of lactation

Radioimmunology was used to determine leptin and ghrelin levels in sow colostrum and milk in relation to those in sow and neonatal pig blood plasma and to the body weight of piglets during the first week of lactation. The highest concentration of leptin was found in colostrum on the second day of lactation (69.3 ± 6.3 ng/mL). Leptin concentrations in sow plasma were significantly lower than in colostrum/milk (2.19 ± 0.9 ng/mL, P = 0.7692) and were stable in the first 7 days of lactation. Total and active ghrelin concentrations in colostrum/milk were stable in the measured time points (6734 ± 261 pg/mL, P = 0.3397; 831 ± 242 pg/mL, P = 0.3988, respectively). Total ghrelin concentrations in sow plasma were lower than in colostrum/milk. These results indicate that pigs follow a unique species‐specific pattern of leptin and ghrelin synthesis, release and existence, and that the mammary gland is an important source of leptin and ghrelin contained in colostrum/milk.     

Assessment of pregnancy‐associated glycoprotein (PAG) concentrations in swamp buffalo samples from fetal and maternal origins by using interspecies antisera

Pregnancy‐associated glycoproteins (PAG) constitute a large family of glycoproteins found in the outer placental epithelial cell layer of the placenta in Eutherian species. In ruminants, they are noted to be structurally closely related among the different species. This study was designed to determine PAG concentrations in maternal and fetal plasma, allantoic and amniotic fluids in buffalo species. Antisera (AS) generated in rabbits against distinct PAG molecules were used in three radioimmunoassay (RIA)‐PAG systems: RIA‐1 (antiserum raised against bovine PAG67kDa; AS#497), RIA‐2 (antiserum raised against caprine PAG55 + 62 kDa; AS#706) or RIA‐3 (antiserum raised against buffalo PAG; AS#859). Samples were collected at a slaughterhouse (n = 67). PAG concentrations determined by RIA‐2 gave significantly higher results in both allantoic and amniotic fluids (12.7 ± 2.1 ng/mL and 24.0 ± 7.3 ng/mL, respectively). Regarding maternal and fetal plasma, PAG concentrations obtained by RIA‐2 (21.8 ± 2.4 ng/mL and 20.2 ± 2.5 ng/mL, respectively) and RIA‐3 (25.0 ± 2.2 ng/mL and 21.9 ± 3.2 ng/mL, respectively) were higher than those obtained by RIA‐1 (15.5 ± 1.4 ng/mL and 16.1 ± 1.8 ng/mL, respectively). The correlation among the three systems was very high. The study clearly reveals the ability of different PAG‐RIA systems to measure PAG concentration in swamp buffalo samples.     

Distribution and prevalence of footrot in Bhutan

The first cases of footrot in Bhutan were reported in sheep in 1990 at the National Sheep Breeding Centre (NSBC), which supplies breeding animals to village sheep flocks throughout Bhutan. Despite the presence of footrot at the Centre the distribution of apparently disease-free sheep continued. Cases of footrot were reported in village flocks soon after the disease was diagnosed at NSBC. A national survey was designed to establish the distribution and prevalence of footrot in Bhutan. This detected footrot in 19/94 village sheep flocks surveyed. The 19 affected flocks were distributed among nine different administrative districts whereas the villages selected were in 13 of a total of 16 sheep growing districts. The highest within-flock prevalences were among the seven flocks sampled in Bumthang district (mean 20.4%). The prevalence of the disease within flocks was generally much lower in other affected districts and in three districts a single affected animal was identified in the sample of 14 sheep examined in each village. Nationally, footrot prevalence was estimated to be 3.1% (95% CI 2.16-4.04%). There was a positive association between the receipt of animals from NSBC and the presence of footrot. The prevalence of the disease was higher in flocks with a migratory system of management than in those using a sedentary system. The relative risk of there being footrot in a migratory flock was nine-times higher than in a non-migratory flock. Only one strain of Dichelobacter nodosus (serogroup B) was identified among the 234 isolates obtained from the 19 affected flocks. Sheep with footrot healed quickly when treated with a vaccine made from this strain.     

The levels of selenium and glutathione peroxidase activity in blood of sheep, cows and pigs.

The levels of selenium (Se) and glutathione peroxidase (GPX) in the blood of sheep, cows and pigs under farm conditions were examined. Sheep appear to form two distinct groups, namely high Se and GPX and low Se and GPX. The high group gave ranges of 133-249 ng/ml and 77-179 iu/g Hb for blood Se and GPX respectively, while the low group showed levels of 21-67 ng/ml and 2-20 iu/g Hb. Overall sheep blood showed a high correlation between Se and GPX (r = 0-92, P less than 0-001). Cow bloods formed one group, all having low Se and GPX levels except for a single outlier. Omitting this animal, the overall ranges were 9-72 ng/ml and 6-36 iu/g Hb for Se and GPX respectively. Blood Se and GPX activity were significantly correlated (r = 0-59, P less than 0-001). Pigs formed a single group also, with the difference that while their blood Se was high, the corresponding blood GPX activities were relatively low. Overall ranges were 93-193 ng/ml and 17-69 iu/g Hb for Se and GPX respectively. Correlation between blood Se level and GPX activity in this species was not significant (r = 0-27, P more than 0-1).     

Observations on the indirect transmission of virulent ovine footrot in sheep yards and its spread in sheep on unimproved pasture

SUMMARY: Virulent ovine footrot was transmitted accidentally to a group of 23 adult Merino sheep (flock B) after holding for 1 hour in sheep yards, which earlier the same day had contained another flock (flock A) with < 1% prevalence of sheep with footrot lesions. Sheep in flock B were rendered susceptible to virulent footrot by grazing 600 mm high unimproved pasture dominated by paspalum ( Paspalum dilatatum ) and kangaroo grass ( Themeda australis ) during warm, humid and wet weather. In addition to moisture, interdigital abrasions caused by the pasture might have predisposed the interdigital skin to infection with Dichelobacter nodosus .     

Factors associated with the effectiveness of antibiotic treatment for ovine virulent footrot

Factors associated with the proportion of sheep cured of virulent footrot after antibiotic treatment were studied in a field trial under dry environmental conditions. From 2 similar flocks, 1091 Merino sheep weighing about 50 kg and infected with virulent footrot received an intramuscular injection of either 12 mL of a mixture of penicillin (250 mg/mL) and streptomycin (250 mg/mL), 6 mL of long acting oxytetracycline (200 mg/mL) or 6 mL of a mixture of lincomycin (50 mg/mL) and spectinomycin (100 mg/mL). Variables that were significantly associated with the proportion of sheep cured were: the type of antibiotic used, the number of feet infected and the flock from which the sheep came. There was an interaction between antibiotic type and number of feet infected and between antibiotic type and flock in association with the proportion of sheep cured. The extent of paring and the occurrence of blowfly strike in footrot lesions treated with diazinon had no significant association with the proportion of sheep cured.     

Feeding value of different levels of malt sprout and katikala atella on nutrient utilization and growth performance of sheep fed basal diet of Rhodes grass hay

Nonconventional agro-industrial by-products such as traditional liquor residues (locally called katikala atella) are widely used by livestock farmers in Ethiopia. The objective of this experiment was to evaluate the supplementary value of katikala atella and malt sprout (MS) on performance of sheep fed a basal diet of Rhodes grass hay. Thirty intact yearling male sheep with an average initial body weight of 17.4?±?0.74 kg (mean?±?SD) were assigned to the treatments in a completely randomized block design: atella alone (T1), 75 % atella?+?25 % malt sprout (MS) (T2), 50 % atella?+?50 % MS (T3), 25 % atella?+?75 % MS (T4), MS alone (T5), and Rhodes grass hay alone (T6). Grass hay was fed ad libitum to all treatments. The total dry matter (DM) and organic matter (OM) intakes of sheep fed T4, T5, and T3 diets were the highest (P?<?0.05), while sheep receiving T6 had the lowest DM intake. The highest (P?<?0.05) total crude protein (CP) intake was for sheep fed T5 diet, while the lowest was for those fed T6 diet. Sheep receiving T3 diet had higher (P?<?0.05) DM, OM, CP, neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility as compared with those fed T1, T2, and T6 diets. Sheep supplemented with 50–100 % malt sprout had similar (P?>?0.05) DM, OM, CP, NDF, and ADF digestibility. The highest (P?<?0.05) average daily gain was for sheep fed T3, T4, and T5 diets, while sheep in T6 lost body weight. Sheep fed T5 diet had the highest (P?<?0.05) nitrogen retention, while those fed T6 diet had the lowest. The study has shown that a mixture diet consisting of equal parts of katikala atella and malt sprout (T3) are found to be superior in most of the required nutrient characteristics.