Gossypol toxicity in preruminant calves

SUMMARY Twenty-four of 57 calves fed a diet containing 33% cotton seed meal (CSM) died between 7 and 15 weeks of age. Initial deaths were not accompanied by premonitory signs, but after CSM withdrawal most calves developed rough coats, anorexia, weakness, ascites and subcutaneous oedema. Those that died had large volumes of serous fluid in the body cavities, hard livers of ‘nutmeg’ appearance, and pulmonary congestion. Histopathologically the livers showed periacinar necrosis in acute cases and periacinar fibrosis in chronic cases. Lungs from several calves had oedema, haemosiderosis and fibrosis in some pulmonary vessels. Atrophy of myocardial fibres was present in most cases. The concentration of free gossypol in the diet was 100 to 220 mg/kg. Ante-mortem and post-mortem findings supported a diagnosis of gossypol poisoning. The deaths continued for 4 weeks after withdrawal of CSM from the diet.     

Acute cortisol responses of calves to scoop dehorning using local anaesthesia and/or cautery of the wound

Objective To measure plasma cortisol responses in calves dehorned using a scoop after administration of local anaesthesia and/or cautery of the wounds.
Design A physiological study with controls.
Procedure There were six treatments: control handling with and without local anaesthesia, dehorning, dehorning after local anaesthesia, dehorning followed by wound cautery, and dehorning after local anaesthesia followed by wound cautery. Blood samples were taken before and after dehorning.
Results Dehorning caused an increase in plasma cortisol concentrations, which decreased a little to plateau values and then declined to pretreatment values 3 to 4 h after dehorning. The peak was smaller after local anaesthesia was administered but when its effects wore off, cortisol concentrations increased and thereafter were similar to those in the dehorned animals. The combination of local anaesthesia and cautery resulted in a plasma cortisol response similar to those in control calves with or without local anaesthesia.
Conclusions If plasma cortisol concentrations reflect the distress being experienced by the calves, then local anaesthesia reduces the acute distress for about 3 h after dehorning but not during the subsequent 3 to 4 h. Combining local anaesthetic and cautery prevented the significant increase in plasma cortisol following dehorning and may eliminate the acute distress caused by scoop dehorning.     

Antimicrobial drug use and related management practices among Ontario swine producers

A mail survey of swine producers in Ontario was undertaken during 1991 to describe the types, frequency, and motives for antimicrobial use. Two hundred operations that marketed fewer than 350 hogs per year, and 800 that marketed more than 350 per year were sent questionnaires, 63% of which were completed and returned. Most operations (86%) added antimicrobials to starter (weanling pig) rations, while fewer (29%) added these drugs to finisher pig rations. The most commonly used antimicrobials were tylosin, carbadox, and furazolidone in weanling pigs, and tylosin, lincomycin, and tetracycline in finishers. Water medication of grower-finisher pigs was practised on 25% of farms; 80% of farms had injected at least some grower-finisher pigs with antimicrobials in the 12 mo preceding the survey. Approximately 20% of operations that added antimicrobials to finisher rations did so for growth promotion purposes only, while others used them for disease treatment, prevention, control, or a combination of reasons. Among those not using antimicrobials in finisher rations, 83% did not believe they were necessary and 37% were concerned about the potential for residues in marketed hogs.     

Associations among antimicrobial drug treatments and antimicrobial resistance of fecal Escherichia coli of swine on 34 farrow-to-finish farms in Ontario, Canada

Logistic regression was used to model associations between antimicrobial treatment and resistance among fecal Escherichia coli of finisher pigs at the farm level. Four sets of potential risk factors representing different levels of refinement of antimicrobial use on farms were modelled on resistance to antimicrobials. Final models for each antimicrobial were constructed from treatment and management variables significant on initial screening, and corrections for overdispersion were made. In general, in-feed antimicrobial treatment of pigs was more consistently associated with an increased risk of resistance than individual-animal treatment. Antimicrobial treatment in starter rations was significant in final models of resistance to ampicillin, carbadox, nitrofurantoin, sulfisoxizole, and tetracycline. Treatment in grower–finisher rations was significantly associated with resistance to ampicillin, spectinomycin, sulfisoxizole, and tetracycline. There was little evidence that in-feed antimicrobials increased the risk of resistance to gentamicin, which is a drug used only for individual-pig treatment in this study population. These results suggest that antimicrobial medication of rations of post-weaning pigs selects for and maintains antimicrobial resistance among E. coli of finisher pigs. Although resistance was common on farms that did not medicate rations of post-weaning pigs, the results indicate that antimicrobial use does increase the risk of resistance to the antimicrobials studied.     

Effect of Initial GnRH and Duration of Progesterone Insert Treatment on the Fertility of Lactating Dairy Cows

The study compared response to prostaglandin F2α (PG), synchrony of ovulation and pregnancy per AI (P/AI) in a 5‐ vs a 7‐day Ovsynch + PRID protocol and investigated whether the initial GnRH affects P/AI in lactating dairy cows. Two hundred and seventy‐six cows (500 inseminations) were assigned to one of four timed‐AI (TAI) protocols: (i) PRID‐7G; 100 μg GnRH im, and a progesterone‐releasing intravaginal device (PRID) for 7 days. At PRID removal, PG (500 μg of cloprostenol) was given im. Cows received the second GnRH treatment at 60 h after PRID removal and TAI 12 h later. (ii) PRID‐5G; as PRID‐7G except the duration of PRID, treatment was 5 days and PG was given twice (12 h apart). (iii) PRID‐7NoG; as PRID‐7G except the initial GnRH, treatment was omitted. (iv) PRID‐5NoG; as PRID‐7NoG except the duration of PRID, treatment was 5 days. Response to treatments and pregnancy status at 32 and 60 days after TAI was determined by ultrasonography. The percentage of cows ovulating before TAI was greatest in PRID‐7G (17.1%), and the percentage of cows that did not have luteal regression was greatest in PRID‐5G (9.5%). The overall P/AI at 32 and 60 days did not differ among TAI protocols. However, during resynchronization, cows subjected to the 5‐day protocols had greater (p < 0.05) P/AI (45.3% vs 33.6%) than cows subjected to the 7‐day protocols. Pregnancy loss between 32 and 60 days tended (p = 0.10) to be greater in cows that did not receive initial GnRH (14.8%) compared to those that received GnRH (8.2%). In conclusion, the PRID‐5G protocol resulted in fewer cows responding to PG, but P/AI did not differ among TAI protocols. A 5‐day protocol resulted in more P/AI in resynchronized cows, and cows that did not receive initial GnRH tended to experience more pregnancy losses.     

Effect of the route of administration on the mucosal and systemic immune responses to Lawsonia intracellularis vaccine in pigs

In an on‐farm study, 40 weaned piglets aged 3 weeks were vaccinated with Lawsonia intracellularis vaccine orally, IM or IP while a fourth group remained unvaccinated. All vaccinated animals showed increased serum levels of L. intracellularis‐specific IgG antibodies, but significantly elevated concentrations of specific IgG, IgA and cytokines were generated in ileal mucosal secretions from the orally and IP vaccinated pigs when examined at 17 days after vaccination.     

Using social media as a cost‐effective resource in the photo‐identification of a coastal bottlenose dolphin community

1. Bottlenose dolphins encountered around the Irish coast are considered part of a wide‐ranging coastal community; however, knowledge on the significance of the north of Ireland for this species is limited by a lack of dedicated effort.
2. Through social media, the opportunity now exists to gather large volumes of citizen science data in the form of high‐quality images, potentially extending the spatial and temporal scope of photo‐identification studies.
3. The purpose of this study was to investigate social media as a data resource for photo‐identification studies and to provide a preliminary assessment of bottlenose dolphins in the north of Ireland. Specifically, the study sought to examine the photo‐identification data for spatial clustering.
4. The study identified 54 well‐marked individuals and provided evidence of potential year‐round occurrence, with successful re‐sightings throughout the study period (2007–2016). There was a geographic concentration of re‐sightings along the north of Ireland, suggestive of interannual site fidelity. These results provide scientific rationale for strategically targeting the north of Ireland in future research on the Irish coastal community.
5. For effective conservation of the bottlenose dolphin it is imperative that scientific research, and resultant management objectives, consider wide‐ranging communities such as the Irish coastal community. Our research highlights data collection via social media as a cost‐effective and scientifically valuable tool in the photo‐identification of coastal cetaceans. We recommend that this method is used in research on low‐density and wide‐ranging coastal cetaceans.

     

The effect of footrot on body weight and wool growth of sheep

Body weight and traits associated with production of wool were measured over a 2-year period between 1985 and 1987 in south-western New South Wales in a flock of Merino wethers experimentally infected with footrot. The disease was allowed to spread freely amongst 150 of the flock but kept at very low prevalence in the remaining 50 by preventive footbathing during transmission periods. Severe, underrunning footrot had a significant adverse effect on body weight, for each year of the trial. Body weight was most severely reduced at times of the year when footrot was spreading among animals and lesions were severe. The mean body weight of the infected group at the end of the 2 years of observation was 7.3 kg (11.6%) below that of the control group. Footrot also depressed wool growth, with the mean clean fleece weight of the infected group being 0.4 kg (8%) lighter than that of the controls at each of the 2 annual shearings. There were no consistent differences between the groups for the other wool characteristics measured.