Prevalence of megabacteria in budgerigar colonies

Objective To measure the prevalence of megabacteria in budgerigar-breeding colonies and to evaluate possible methods to reduce the prevalence.
Design A monitoring study over several years.
Sample population Two budgerigar ( Melopsittacus undulatus ) colonies with over 300 birds each.
Procedure The prevalence of megabacteria in the faeces in two budgerigar breeding colonies, colony 1 and 2, was determined by faecal examination of each bird. Following an initial survey (1990), most of the birds that were scored 2+ or more were culled and a management practice was implemented to discriminate against positive birds. Consecutive yearly surveys (1991, 1992) were conducted on the young birds bred in these colonies. The prevalence of megabacteria in colony 2 was also evaluated in 1994 and 1996 after all the birds were treated with amphotericin B administered in drinking water.
Results The prevalence of megabacteria in the two colonies was significantly (P < 0.001) different. Overall the prevalence of megabacteria adjusted for colony differences was significantly higher (P < 0.025) in males compared to females. Age was not an influencing factor. After the initial survey, the prevalence in the offspring did not significantly (P > 0.05) decrease in the following two annual breeding seasons but by inference it did significantly decrease after amphotericin B treatment.
Conclusion The practice of culling most birds with more megabacteria in faeces and discriminating against positive birds when selecting birds for breeding or culling birds on show quality does not decrease megabacteria prevalence in the offspring. However, a reduction in prevalence does occur with administration of amphotericin B. Birds may have amphotericin B-resistant organisms and these birds need to be identified and culled.     

Environmental mastitis in intensive high‐producing dairy herds in New South Wales

Objective To determine the prevalence of mastitis pathogens in high‐producing intensive dairy herds in New South Wales. Design Field survey. Procedure Milk samples from the mastitis‐affected quarter were collected from cows on five high‐producing dairy farms in NSW. The 820 samples were cultured using standard microbiological culture techniques. Results Bacteria or fungi were isolated from 83.3% of samples (683/820). More than two colony types were isolated from 16.7% of samples (137/820), two types from 6.6% (54/820), and one type from 52.3% (429/820). No bacteria were isolated from 24.4% (200/820) of the primary cultures, but enrichment cultures of these samples yielded single colony type bacterial isolates from 36.5% (73/200) of samples. Environmental pathogens, including coliforms, environmental Streptococcus and Staphylococcus spp., made up 91% (555/610) of isolates and accounted for 33.6% (205/610), 41.6% (254/610) and 15.7% (96/610), respectively, of isolates. Escherichia coli accounted for 76.1% (156/205) of the coliform isolates, Streptococcus uberis and Streptococcus dysgalactiae accounted for 32.3% (82/254) and 28.0% (71/254), respectively, of the environmental streptococcal isolates. Contagious pathogens were uncommon, comprising only 2.5% (15/610) of the total isolates. Conclusion The incidence and causes of mastitis are largely influenced by farm management. The relatively high prevalence of coliform mastitis in the intensive high‐producing herds in this survey contrasts with the low incidence reported in surveys of pasture‐based herds in Victoria. If the Australian dairy industry continues its current trend of intensification, coliform intra‐mammary infections may emerge as an increasingly important cause of mastitis.     

Gonadotropin‐Releasing Hormone Administration to Dairy Cows without a Corpus Luteum 4 Weeks after Calving Increases Reproductive Performance

This field study investigated whether the administration of a single dose of gonadotropin‐releasing hormone (GnRH) to dairy cows without a corpus luteum (CL) 4 weeks after calving can improve reproductive performance. Holstein dairy cows underwent ultrasonography to assess the presence of ovarian structures at 29.2 ± 5.2 days post‐partum, and cows were divided into two main groups based on the presence (CL group, n = 230) or absence (non‐CL group, n = 460) of a CL. The non‐CL group was further randomly divided into two subgroups based on the administration of GnRH (non‐CL GnRH group, n = 230) or no GnRH (non‐CL control group, n = 230). Subsets of cows from non‐CL control (n = 166) and non‐CL GnRH (n = 175) groups received a second ultrasonography at 44.5 ± 5.4 days post‐partum to assess CL formation. The percentage of cows with CL at the second ultrasonography was greater in the non‐CL GnRH group (70.9%) than in the non‐CL control group (53.0%, p = 0.0006). The hazard of the first post‐partum insemination by 150 days in milk (DIM) was higher in the CL group than in the non‐CL control group (hazard ratio [HR]: 1.36, p = 0.001). The probability of a pregnancy to the first insemination was higher in non‐CL GnRH (odds ratio [OR]: 1.50, p = 0.04) and CL groups (OR: 1.55, p = 0.03) compared to the non‐CL control group. Furthermore, the hazard of pregnancy by 210 DIM was higher in non‐CL GnRH (HR: 1.30, p = 0.01) and CL (HR: 1.51, p = 0.0001) groups than in the non‐CL control group. In conclusion, administration of GnRH to dairy cows without a CL 4 weeks after calving was associated with an increase in ovulation and improved reproductive performance.     

Assessing obesity in adult dogs and cats presenting for routine vaccination appointments in the North Island of New Zealand using electronic medical records data

Aims: To assess the prevalence of obesity in adult dogs and cats presented to first-opinion veterinary clinics in the North Island of New Zealand for routine vaccination appointments, using electronic medical records.

Methods: Ten first-opinion veterinary clinics across the North Island of New Zealand provided electronic medical records for all routine vaccination appointments for adult (>1 year old) dogs and cats between 1 January 2011 and 30 June 2016. Animals with a body condition score (BCS) of 6 or 7 on a 9-point scale and 4 on a 5-point scale were classified as overweight; those with a BCS of 8 or 9 on a 9-point scale and 5 on a 5-point scale were classified as obese. A total of 106,144 records were available over the study period, of which 48,041 (45.2%) had both a recorded weight and BCS.

Results: Of the 24,247 records for dogs with both BCS and weight, 6,324 (26.1%) were classified as overweight, and 551 (2.3%) as obese. The prevalence of dogs classified as overweight or obese was highest in dogs aged between 5–13 years. The odds of desexed dogs being classified as overweight or obese was greater than the odds for intact dogs (OR=1.42 (95% CI=1.29–1.57), p<0.001) adjusting for the effects of age. Of the 23,794 records for cats with a recorded weight and BCS, 5,222 (21.9%) were classified as overweight, and 622 (2.6%) as obese. The prevalence of cats classified as overweight or obese was highest in cats aged between 5–11 years. The odds of desexed cats being classified as overweight or obese tended to be greater than the odds for intact cats (OR=1.14 (95% CI=0.98–1.31); p=0.075), adjusting for the effects of age.

Conclusions: Although there are limitations with using electronic medical records to estimate the prevalence of obesity in companion animal populations, the results highlight that a significant number of animals presenting for routine vaccination appointments were classified as overweight or obese.

Clinical Relevance: It is important for veterinarians to record both patient body condition and weight during routine preventative care appointments to allow accurate ongoing monitoring of trends in obesity at both the patient and population levels.

Abbreviations: BCS: Body condition score