Field trials of a formulation containing moxidectin and 6 in 1 vaccines for sheep

Objective: To assess the efficacy and safety of a formulation containing moxidectin and 6 in 1 vaccine in sheep under field conditions.
Design: Efficacy and safety study.
Animals: Two hundred and five crossbred Merino lambs and two hundred and eight Merino ewes were used in the studies.
Procedure: A formulation was made for the simultaneous treatment of sheep with moxidectin and immunisation against clostridial diseases and caseous lymphadenitis. The efficacy against nematodes, vaccine response and safety were assessed.
Results: Effective control of nematodes and responses to antigens were achieved following subcutaneous administration. The formulation was safe to administer; occasional minor tissue reactions were evident, but no other adverse effects of treatment were observed in either pregnant ewes or lambs, using either the recommended dose, or an overdose of the formulation.
Conclusion: Administration of a formulation containing moxidectin, five clostridial antigens and caseous lymphadenitis antigen proved safe and efficacious under field conditions.     

Patterns of Follicular Growth in Superovulated Sheep and Influence on Endocrine and Ovarian Response

Objectives of this study were to characterize patterns of follicular development in sheep superovulated with purified follicle stimulating hormone (FSH) (OVAGEN^TM, ICP, Auckland, New Zealand) and to determine its influence on preovulatory events (onset of the oestrus behaviour and timing of the preovulatory luteinizing hormone surge) and ovarian response (ovulation rate and embryo yield). Number and size of all ≥ 23 mm follicles from the first FSH injection to withdrawal of progestagen sponges was determined by transrectal ultrasonography just prior to every FSH injection in nine Manchega ewes superovulated with eight decreasing doses (ml) (1.5 × 3, 1.25 × 2 and 1 × 3) of OVAGEN injected twice daily from 60 h before to 24 h after the withdrawal of 40 mg fluorogestone acetate sponges. Oestrous detection and jugular blood sampling for LH radioimmunoassay were performed every 3 h from 14 to 53 h after sponge removal and ovulation rate and number of embryos were determined 4 days after progestagen withdrawal. Administration of OVAGEN induced a significant rise (p < 0.0005) in the number of follicles ≥ 4 mm in size because of an increased growth in size of follicles from the first FSH injection to sponge removal, an increase in the number of newly detected follicles from 12 to 36 h of the first FSH dose (p < 0.005) and a decrease in regression rate from 24 h (p < 0.001). The number of follicles 2–3 mm in size at first FSH dose (10.4 ± 1.5) was positively correlated with the number of ≥ 4 mm follicles at 0 h (19.0 ± 2.7, p < 0.01). A higher number of ≥ 4 mm follicles at 0 h was related with an earlier appearance of oestrus (31.5 ± 1.5 h, p = 0.08) and LH surge (45.0 ± 2.3 h, p < 0.005), and a higher ovulation rate (18.2 ± 3.8, p < 0.005). On the other hand, the rate of embryo recovery was decreased in ewes with earlier preovulatory LH peaks (p < 0.005), with a shorter interval between oestrus and LH peak (p < 0.05).     

Individual and group antimicrobial usage rates on 34 farrow-to-finish swine farms in Ontario, Canada

Antimicrobial drug-use was assessed on 34 farrow-to-finish operations that marketed at least 500 hogs/yr. These operations either did not use any antimicrobials or used narrow-spectrum or broad-spectrum antimicrobials in rations of post-weaning pigs. Total antimicrobial use was measured for two months after obtaining inventories and records of all antimicrobials used. The collection of empty medication bottles and inventories of drugs on hand was convenient for producers and useful for estimating or validating recorded treatment rates, particularly for antimicrobials that were used only in one class of pig. Treatment records, however, underestimated by approximately 35% the amounts used for 27/29 farm–antimicrobial combinations. Rates of individual-pig treatment varied from 0–24.1 pigs treated/1000 pig-days, with a median of 5.29. Most individual animal treatments were given to piglets and sows at parturition and penicillin was the most commonly used antimicrobial. Gentamicin was administered to suckling piglets on 19 of the farms.     

An evaluation of vulvomucosal injections of prostaglandins for induction of parturition in swine

Two trials were performed to evaluate the efficacy of prostaglandins administered via the vulvomucosal route at one-half the recommended dosage in comparison to prostaglandins injected intramuscularly (IM) at the standard dosage. In trial 1, sows on three commercial swine farms were given prostaglandin F2α at a dosage of 10 mg IM (n = 110) or 5 mg prostaglandin F2α using a vulvomucosal injection (n = 94). The numbers of sows farrowing within 36 h postinjection were 92 (84%) and 83 (88%), respectively. In trial 2, sows on four commercial swine operations were induced to farrow by means of one of three treatments: cloprostenol 175 μg IM (n = 71); cloprostenol 87.5 μg vulvomucosally (n = 57); or prostaglandin F2α 5 mg vulvomucosally (n = 96). The numbers of sows farrowing within 36 h postinduction were 69 (97%), 53 (93%), and 91 (94%), respectively.

Vulvomucosal injections of prostaglandin F2α and cloprostenol at one-half the dosage appeared to be as effective as intramuscular injections of prostaglandin F2α and cloprostenol at the recommended level. There were fewer sows demonstrating restless behavior following the injection of lower dosages of prostaglandin F2α vulvomucosally, compared to sows given the recommended dosage of prostaglandin F2α IM.

     

Autumn abortions in sows

This report describes the diagnosis and management of autumn abortions in a commercial swine herd in Ontario. A consistent pattern of abortions in the fall (and to a lesser extent, winter and spring) months was established from the herd records of 1980 to 1982. The percent abortions (of all farrowings) was 2.2, 3.7 and 4.3 for the years 1980, 1981 and 1982 respectively. Since laboratory examinations did not identify a specific pathogen, the management and the environment were investigated. In December 1982, supplemental heat was provided in the gestation barn to counteract heat losses at the level of the pregnant sows. The percent abortions was reduced to 0.4 over the next 12 months.     

Piglet blood glutathione peroxidase levels and preweaning mortality.

The blood glutathione peroxidase levels of one day old piglets from 22 litters were examined. Body weight and piglet survival were monitored in order to assess the relationship between these two factors and blood glutathione peroxidase activity. The mean blood glutathione peroxidase level of one day old piglets (65 mu/gHb) was significantly lower (p0.001) than the mean level (85 mu/gHb) at weaning. The mean blood glutathione peroxidase activity of one day old piglets was not related to the size of the litter, but was related (p less than 0.1) to the mean litter blood glutathione peroxidase level at weaning time. Piglet blood glutathione peroxidase was not related to piglet body weight. The blood glutathione peroxidase level of the sows at one-day post-farrowing was not related to the mean blood glutathione peroxidase activity of their litters at one day of age but was correlated (p less than 0.1) with the mean blood glutathione peroxidase levels of their litters at weaning. Piglet viability was shown to be strongly correlated (p less than 0.001) with body weight at one day of age. The blood glutathione peroxidase level of one day old piglets was weakly associated (p less than 0.1) with piglet survival. Further work is required to clarify this latter observation, which suggests that selenium supplementation to newborn piglets may be beneficial regardless of the dams nutritional status.     

Prevalence of respiratory diseases and their association with growth rate and space in randomly selected swine herds.

The prevalence and extent of respiratory tract lesions were measured in 1425 pigs from 27 randomly selected herds in the summer of 1982 and winter of 1983. About 75% of pigs had lesions of enzootic pneumonia, approximately 60% had atrophic rhinitis and approximately 11% had pleuropneumonia and/or pleuritis. Individual pig growth rate was recorded on two of the farms, and it was found that the correlations between growth rate and severity of enzootic pneumonia lesions were positive on one farm and negative on the other. Negative correlations between severity of turbinate atrophy and growth rate existed in one of the two herds. Extent of pneumonia and severity of turbinate atrophy were poorly related in individual pigs but herd averages were moderately and positively correlated. Prevalence of diffuse pleuritis and of pleuropneumonia were positively related, as were the extent of pneumonia and prevalence of localized pleuritis. Prevalence of pleuropneumonia was strongly correlated with increased days-to-market. A method of estimating the average days-to-market using weekly herd data (inventory) was developed.     

Prevalence of Actinobacillus pleuropneumoniae, Actinobacillus suis, Haemophilus parasuis, Pasteurella multocida, and Streptococcus suis in representative Ontario swine herds

Tonsillar and nasal swabs were collected from weanling pigs in 50 representative Ontario swine herds and tested for the presence of 5 important bacterial upper respiratory tract pathogens. All but 1 herd (2%) tested positive for Streptococcus suis by polymerase chain reaction (PCR); 48% of herds were S. suis serovar 2, 1/2 positive. In all but 2 herds there was evidence of Haemophilus parasuis infection. In contrast, toxigenic strains of Pasteurella multocida were detected by a P. multocida--enzyme-linked immunosorbant assay (PMT-ELISA) in only one herd. Seventy-eight percent of the herds were diagnosed positive for Actinobacillus pleuropneumoniae by apxIV PCR. Sera from finishing pigs on the same farms were also collected and tested by ELISA for the presence of A. pleuropneumoniae antibodies. Seventy percent of the herds tested had evidence of antibodies to A. pleuropneumoniae including serovars 1-9-11 (2%), 2 (4%), 3-6-8-15 (15%), 5 (6%), 4-7 (26%), and 12 (17%). This likely represents a shift from previous years when infection with A. pleuropneumoniae serovars 1, 5, and 7 predominated. At least 16% and possibly as many as 94% of the herds tested were Actinobacillus suis positive; only 3 of the 50 herds were both A. pleuropneumoniae and A. suis negative as judged by the absence of a positive PCR test for apxII. Taken together, these data suggest that over the past 10 years, there has been a shift in the presence of pathogenic bacteria carried by healthy Ontario swine with the virtual elimination of toxigenic strains of P. multocida and a move to less virulent A. pleuropneumoniae serovars. As well, there appears to be an increase in prevalence of S. suis serovar 2, 1/2, but this may be a reflection of the use of a more sensitive detection method.     

Expression profiles of immunity and reproductive genes during transition period in Holstein cattle

The transition period is a critical time for dairy cows as the animal is subjected to the physiological stress accompanying parturition. Immunosuppression and health status were examined during this period in 80 Holstein cows. Blood samples were taken from each cow 3, 2 and 1 week before and after calving, and at calving (0 day). RNA was extracted and subjected to real‐time PCR to determine mRNA levels for the immune‐related genes TLR 2, 4, 6, 7 and β‐defensin 5 in addition to the reproduction‐related genes prolactin and IGF‐I. Results showed significant up‐regulation of pro‐inflammatory‐selected genes, TLR 4, 6 7 and β‐defensin 5 at the third‐week post‐calving; however, earlier periods had lower expression of such genes. In contrast, the immunosuppression biomarker TLR2 gene was up‐regulated at calving and 1 week after parturition and then down‐regulated again at second and third week. Prolactin and IGF‐I genes expression levels were significantly and gradually increased mainly post‐partum. This research highlights that the expression patterns of TLRs, BNBD5, PRL and IGF‐I could be biomarkers to follow up immune and reproductive status of dairy cow at peri‐parturient period to predict the most susceptible risk time for disease incidence and to build up management protocol.