Four shed-lambing operations in western Colorado were monitored during the 1984 spring lambing season to determine the causes and rates of perinatal lamb mortality. The number of lambing ewes per flock ranged from 513 to 1,712, and lambing percentages ranged from 131 to 180%. Overall perinatal lamb mortality ranged from 8.2 to 12.2%. Most lamb deaths occurred during parturition or within 24 hours after parturition. More than 85% of all lamb deaths were in lambs born to ewes having 2 or more lambs. The leading causes of lamb death were starvation, dystocia, stillbirth (unknown cause), and infectious diseases. A wheel model was used to categorize factors causing lamb deaths into 4 groups: physical, social, host, and biological, and to present data on perinatal lamb mortality in a simple visual model. In all flocks, social and biological factors resulted in most of the lamb deaths. On the basis of our findings, we suggest that interventions designed to improve ewe-lamb bonding and to reduce infectious agents and the incidence of prolonged parturition may reduce lamb mortality.

We compared the ability of 2 alpha2-adrenergic receptor antagonists, atipamezole and yohimbine, to reverse medetomidine-induced CNS depression and cardiorespiratory changes in lambs. Twenty lambs (7.8 +/- 2.6 kg) were randomly allotted to 4 treatment groups (n = 5). Each lamb was given medetomidine (30 micrograms/kg of body weight, IV), followed in 15 minutes by IV administration of atipamezole (30 or 60 micrograms/kg), yohimbine (1 mg/kg), or 0.9% NaCl (saline) solution. Medetomidine caused lateral recumbency in 1 to 2 minutes in all treated lambs. Medetomidine significantly (P < 0.05) decreased heart rate at 5 and 10 minutes after its administration. Heart rate remained above 120 beats/min, and severe bradycardia (< 70 beats/min) and other arrhythmias did not occur throughout the study. Medetomidine also induced tachypnea in all treated lambs. The tachypnea was abolished by atipamezole and yohimbine, but not by saline solution administration. The medetomidine-induced tachypnea did not significantly affect arterial pH and PaCO2. Arterial oxygen tension was within acceptable range (PaO2 = 71 to 62 mm of Hg), but was lower than expected. Administration of atipamezole, yohimbine, or saline solution did not change PaO2 significantly. Lambs treated with 30 or 60 micrograms of atipamezole/kg were able to walk unassisted in 2.4 +/- 0.4 and 2.3 +/- 0.7 minutes, respectively, whereas yohimbine-and saline-treated lambs did not walk unassisted until 15.6 +/- 2.7 and 73.0 +/- 6.8 minutes later, respectively. Results of this study indicated that medetomidine is a potent CNS depressant in lambs. Atipamezole at dosage of 30 or 60 micrograms/kg was equally effective, and was more effective in antagonizing medetomidine-induced CNS depression than was yohimbine.

A serologic survey was conducted to determine the prevalence and seroconversion rates for ovine adenovirus (OAV) serotypes 1-4 and bovine adenovirus (BAV) serotypes 2, 3, and 7 in sheep in Iowa and in surrounding states. For 2 consecutive years, paired serum samples were obtained from 1- to 2-month-old lambs as they entered a ram test station and, again, 2 months later. Sera were tested for adenovirus antibodies by use of a microtitration serum virus-neutralization test. At the time of entry, high prevalence of antibody (titer greater than or equal to 2) was detected to all tested adenoviruses except BAV-3. All adenoviruses were active in the ram test station both years, as indicated by greater than or equal to fourfold increase in adenovirus antibody titer (seroconversion) in some of the lambs. The prevalence and seroconversion rate for OAV-1 was 94.0 and 7.2%, respectively; for OAV-2, 98.6 and 15.1%; for OAV-3, 86.5 and 11.0%; for OAV-4, 98.4 and 13.2%; for BAV-2, 97.6 and 22.4%; for BAV-3, 11.4 and 3.8%; and for BAV-7, 81.6 and 4.5%. The results indicate that adenovirus infections were widespread in the sheep population and that the prevalence of active infection based on seroconversion rates was approximately 45%.

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added to the diets of growing wethers (mean body weight, 34.0 kg) and was evaluated for its ability to diminish the clinical signs of aflatoxicosis. The experimental design consisted of 4 treatment groups of 5 wethers each, consuming concentrations of 0 g of HSCAS and 0 g of aflatoxin (AF)/kg of feed (control; group 1); 20 g of HSCAS/kg (2.0%; group 2), 2.6 mg of AF/kg (group 3); or 20 g of HSCAS (2.0%) plus 2.6 mg of AF/kg (group 4). Wethers were maintained in indoor pens, with feed and water available ad libitum for 42 days. Lambs were observed twice daily and weighed weekly, and blood samples were obtained every 2 weeks for hematologic and serum biochemical analyses and for measurement of mitogen-induced lymphocyte-stimulation index. At the termination of the study, wethers were euthanatized and necropsied. Body weight gain was diminished significantly (P less than 0.05) by consumption of 2.6 mg of AF/kg of feed, whereas body weight of lambs consuming HSCAS plus AF did not differ from that of control wethers. The AF-alone treatment increased serum aspartate transaminase and gamma-glutamyltransferase activities, prothrombin time, and cholesterol, uric acid, and triglyceride values and decreased albumin, glucose, and urea nitrogen values, and urea-to-creatine ratio. A 27% decrease in lymphocyte stimulation index, increased spleen weight (as a percentage of body weight), and decreased liver weight were induced by AF-alone treatment. Results indicate that HSCAS may be a high-affinity sorbent for AF, that 2.6 mg of AF/kg of feed induces signs of aflatoxicosis in growing wethers, that lambs may not be as resistant to the effects of AF as previously thought, that 2.0% HSCAS can substantially reduce the toxic effects of 2.6 mg of AF/kg, and that sorbent compounds may offer a novel approach to the preventive management of aflatoxicosis in livestock.

The aim of the study was to assess the changes of blood parameters in 12 three-week-old Polish Merino sheep subjected to experimental jaagsiekte sheep retrovirus (JSRV) infection.Material and Methods: Haematological (WBC with leukocyte subpopulations: GRA, LYM, MID, and RBC, MCV, MCH, MCHC, HGB, HCT, PLT, and MPV) and biochemical blood parameters (acid/base balance, cation/anion content, and gasometry) were determined in blood samples collected one month after JSRV infection, then at four-week intervals for five consecutive months.Results: A decrease in RBC, HCT, MCV, PLT, MPV, and LYM values in comparison with controls was found in the last month of observation. On the other hand, at the same time, an increase in HGB, MCH, MCHC, WBC, MID, and GRA indices was observed. Moreover, at the end of experiment blood gasometric indices such as pCO₂, HCO₃, and tCO₂, and Na and K ion concentrations were higher in the affected lambs than in the healthy animals. The pH values of the challenged animals exhibited less alkaline character than in the case of controls, which was associated with a decrease in O₂% saturation. However, the majority of differences between JSRV inoculated and control groups was not statistically significant.Conclusion: The observed changes in the examined blood parameters can be considered as prodromal symptoms in the preclinical phase of adenocarcinoma development associated with JSRV infection.

This study was carried out to determine the prognostic importance of troponin enzyme levels in lambs with White Muscle Disease (WMD). Materials and Methods: This study consisted of 50 male and female lambs aged 0-3 months old, 30 of which had clinical white muscle disease (Group I) and 20 of which were healthy (Group II – Control Group). Group I was composed of lambs that showed clinical symptoms of the disease. The disease was also identified by laboratory analysis. The lambs in this group were treated and the course of the disease was followed for 15 days.Compared with the control group, the Group I before treatment results were as follows: AST, LDH, CK, CK-MB, Troponin I and T (P<0.001) were high, while GSH-Px (P<0.001), SOD (P<0.01), Se (P<0.01), Retinol and Tocopherol were low. Compared with the control group, the Group I After Treatment results were as follows: AST, CK, Troponin T (P<0.001) were high, LDH (P<0.01) was high and GSH-Px (P<0.01) was low. Comparing Group I Before Treatment and After Treatment results, AST, CK, CK-MB and Troponin I (P<0.001), as well as GSH-Px, SOD and Se (P<0.01) were high. It was determined that LDH decreased and Tocopherol increased. Whereas Vitamin D3 was determined to be insignificant in all three groups, the levels of CK-MB, Troponin I, Retinol, SOD and Se were insignificant in the After Treatment and control groups, and the Troponin T and retinol values were measured to be insignificant in the Before Treatment and After Treatment groups.To conclude, measuring the AST, CK, CK-MB, LDH values as well as Troponin can be an important parameter for the identification and prognosis of WMD.

Thirty apparently healthy lambs with average weight and age of 5.8±0.5 kg and 15±1.6 days respectively were chosen in Sids Agricultural Research Station belonging to Animal Production Research Institute in Beni-Suef governorate to investigate the effect of castration and docking on maintenance behaviour and blood cortisol level during and after such operations. Lambs were classified into castration (n=10), docking (n=10) and control (n=10) groups. The results revealed that castration and docking could significantly affect the behaviours of standing idle, recumbency, sleep, suckling and ingestion in lambs. Moreover, blood cortisol level was significantly (p<0.05) increased after operation in castrated and docked lambs as compared to the time before, at operation and 3 hours after operation.

This study was conducted to investigate the high mortality of young lambs in two sheep farms in Pekan, Pahang over a period of 3 years. Samples from postmortem of 1,451 lambs below one year of age by a farm veterinarian were submitted for laboratory diagnosis at the Bacteriology Section of the Regional Veterinary Diagnostic Laboratory in Kuantan. Escherichia coli is the most commonly recorded bacteria with 161 lambs diagnosed in 2013. In 2014 and 2015, there was a decrease in occurrence of E. coli related deaths, with 120 and 75lambs respectively. A total of 25% of the cases showed Escherichia coli positive by culture on blood agar and MacConkey agar, and confirmed by biochemical tests. A total of 21% of the cases were positive for staphylococcus sp, 3% and 6% for Streptococcus sp and Klebsiella pneumonia, respectively. Other bacteria were isolated in 45% of the cases. It was further noted that a total of 285 lambs between the ages of one to four months of age followed by 58 lambs (20%) less than one month old had E.coli isolation. It is also noteworthy that there were 10 lambs with E.coli infection in one to fourteen day-old lambs during the 3-year period from January 2013 to December 2015. This information was collated as a result of routine diagnosis of field cases submitted and with the intention of highlighting the common pathogens causing high mortality in local small ruminant farms so that preventive action may be taken for future farming ventures. E. coli infections or Colibacillosis is an important finding and indicator of poor management including poor nutrition, hygiene and environmental contamination which can reduce animal immunity and render it susceptible to other infections.

Few antimicrobials are licensed for use in sheep in Canada, and the range of indications is narrow. Treatment in an “extra-label” manner may be ineffective. In addition, potentially harmful drug residues in food-animal products and antimicrobial resistance in bacteria may be associated with extra-label drug use (ELDU). No data had been documented on drug use, specifically antimicrobial use (AMU), in Ontario sheep, although it was thought that much use was extra-label. This study investigated AMU and ELDU on 49 lamb-producing Ontario sheep farms. Data were prospectively collected over 12 months from the participating farms, and farm-level practices were ascertained with a questionnaire. Treatment-level and farm-level variables were investigated for associations with rates of AMU by means of Poisson rate regression models fit with a generalized estimating equation to control for clustering at the farm level. Antimicrobials with high mean exposure rates included chlortetracycline (in feed), penicillins, and oxytetracycline. The exposure rate in lambs was significantly lower (P < 0.01) with antimicrobial treatment of systemic signs, respiratory disease, or wound or injury than with treatment of other reported diseases or conditions; it was also significantly lower with 3 or more lambing periods per year (α = 0.05). The exposure rate in adult sheep was significantly lower with treatment of 5 of the 6 most prevalent diseases or conditions (α = 0.05) and significantly higher with producer decision to treat and producer experience of 20 y or greater. Rates of using antimicrobials not licensed for use in sheep were high, as was extra-label use of licensed antimicrobials. Diseases reportedly treated most often with antimicrobials (e.g., systemic signs, mastitis) were significantly associated with lower rates of ELDU (α = 0.05). Compared with the rates in adult sheep, the mean rate of use of nonlicensed antimicrobials was similar in the lambs, whereas the mean rate of extra-label use of licensed antimicrobials was lower among the lambs. The results are useful in determining if public health concerns about antimicrobial use in Ontario sheep are warranted and in creating drug use and licensure strategies for the Canadian sheep industry.

Objective—To determine whether selection for the homozygous A136R171 genotype that confers resistance to classic scrapie infection negatively affects production traits in sheep. Animals—996 commercial lambs obtained from 2 flocks at separate locations across 3 consecutive years. Procedures—Genotyping at codon 136 and 171 was performed by use of commercially available testing or a single-nucleotide polymorphism assay. Carcass data were collected without knowledge of genotype approximately 24 hours after slaughter by an experienced grader. The model to analyze associations between prion protein (PRNP) genotype and production traits was based on genotype, breed, or both as fixed effects and days on feed as a covariate. Results—Average daily gain was significantly associated with only combined codons 136 and 171. In flock 1, weaning average daily gain was significantly greater in AA136 sheep than heterozygotes; the difference between QR171 and RR171 sheep, compared with QQ171 sheep, were not significant although QR171 and RR171 sheep had higher values. However, in flock 2, average daily gain was significantly greater in AV136 sheep than AA136 sheep and in QR171 sheep than QQ171 sheep. Conclusions and Clinical Relevance—Findings suggest there is an advantage for average daily gain in lambs with an arginine allele at codon 171, but there were no other genotype effects on production traits. Thus, selection for the resistant arginine allele at codon 171 to comply with USDA scrapie eradication guidelines should not be detrimental to lamb production in commercial flocks. Effects of codon 136 on average daily gain were ambiguous.