New Zealand veterinary journal最新文献

Aims: To compare surgical times and rates of intra-operative and post-operative complications for open ovariohysterectomy (OVH) in female rabbits using conventional ligatures or a vessel sealing device (VSD) for haemostasis.

Methods: Female pet rabbits (n = 23) presented for OVH for either desexing or treatment of reproductive disorders were randomly assigned to a conventional ligatures (CL) group (n = 12) or a LigaSure 5-mm (LS5) group (n = 11). In the CL group, the ovarian pedicles were ligated with a single surgeon's knot. After transection of the ovarian pedicles, the broad ligament was manually broken down along the uterine horns to their respective cervices. In the LS5 group, both ovarian pedicles and the broad ligaments were sealed with a LigaSure Dolphin Tip VSD with 5-mm forceps. All the rabbits were hospitalised for 24 hours after surgery. Two weeks after discharge, a clinical recheck examination was performed. Incision length, overall surgical time (from initial incision to completion of intradermal suturing), OVH time (from identification of the first ovary to transection of the vaginal vault), and intra- and post-operative complications were recorded and compared between groups, using the Student's t-test for normally distributed continuous data, the Wilcoxon-Mann-Whitney test for non-normally distributed continuous data and Pearson's χ² test for categorical data.

Results: The mean overall surgical time was 14.1 (SD 4.4) minutes. The surgery took 15.0 (SD 4.9) minutes in the CL group and 13.1 (SD 3.8) minutes in the LS5 group (p=0.10). The OVH time was shorter in the LS5 group (mean 4.2 (SD 0.9) minutes) than in the CL group (mean 6.3 (SD 1.7) minutes; p = 0.005). No intra-operative complications were encountered in the LS5 group. Haemorrhage occurred in three rabbits in the CL group. One rabbit in the LS5 group developed steatonecrosis post-operatively. There was no evidence of a difference in the proportion of rabbits that experienced intra- and post-operative complications (p = 0.25 and p = 0.94 respectively) between groups.

Conclusions: The use of a LigaSure 5-mm VSD and conventional ligatures during open OVH were both associated with similar overall surgical times and complication rates. The OVH times were shorter in the LS5 group compared to the CL group.

Clinical relevance: Use of the LigaSure 5-mm VSD allows efficient haemostasis while performing open OVH in female pet rabbits.

Aims: To evaluate the effect of sporidesmin toxicity on production outcomes and serum biochemistry analytes in mixed age Romney ewes, using a standardised measure of liver damage.

Methods: This was a prospective longitudinal study following 46 mixed age Romney ewes from sporidesmin intoxication in April 2019, to slaughter 8 months later. The ewes were blood-sampled up to eight times, with a panel of serum biochemistry tests performed on the final six samples. However, only gamma-glutamyl transferase (GGT) activity was measured in the first two samples collected at the end of sporidesmin intoxication and 2 weeks later. Body condition score, ewe weight and production data were also recorded. Using a standardised liver score, based on histology of liver samples collected at slaughter, ewes were assigned to one of three liver disease categories (LDC); low, middle, and high. These were then used as the outcome or predictor variables for statistical analyses. Finally, two separate decision tree models, using recursive partitioning (RP), were fitted to the biochemistry data and to the GGT data collected at FE outbreak, to predict ewes in the low LDC.

Results: There was no evidence of a difference for the effect of LDC on ewe weight (p = 0.86) with ewes, on average, gaining weight to weaning. Weaning percent, lamb rearing percent and ewe flock efficiency were lower in ewes with high LDC, and scanning-to-weaning lamb loss was significantly higher in sheep with high LDC (p = 0.02). Serum activities of GGT and glutamate dehydrogenase and concentration of globulin were significantly lower in sheep with low LDC than in sheep with middle or high LDC (p < 0.05). However, there was no evidence of a difference for the effect of LDC on other biochemistry variables (p > 0.05). The final RP model for the biochemistry data categorised ewes as low LDC if their GGT was <122 IU/L, 3 months after sporidesmin intoxication, or if their GGT was <514 IU/L, <18 days after sporidesmin intoxication.

Conclusions and clinical relevance: Sheep with gross and histological evidence of severe sporidesmin-induced liver damage were able to maintain or gain body weight, suggesting that sporidesmin intoxication alone is not causative of poor body condition. Similarly, many of the serum biochemistry tests were not associated with evidence of liver damage. Lamb production was reduced in ewes with evidence of severe liver damage and the decision tree model showed promise as a basis to select ewes for culling.

Ewe wastage encompasses ewes that do not reach the end of their potential productive lives and is the combination of premature culling and on-farm mortality. Increased ewe wastage results in reduced flock productivity and profitability, primarily driven by the need for increased replacement ewe lambs to maintain flock numbers and the costs associated with these additional replacements (e.g. reduced sale lambs, reduced flock age resulting in lower lamb production, and reduced ability to utilise terminal sires). Annual ewe mortality rates are reported to range from 2.8 to 40.2% in New Zealand commercial flocks, while wastage over a ewe's productive lifespan (i.e. mortality and premature culling combined to 6-7 years-of-age) is reported to be up to 90%. To date, ewe wastage has received relatively little attention in the published literature. This article reviews published studies describing wastage in non-dairy ewes, focusing on New Zealand commercial flocks, although overseas pasture-based data is also considered. The relevance of, and challenges associated with, investigating ewe wastage are discussed. Ewe culling and mortality data is outlined, and causes are described. Known key risk factors for wastage, namely, reproductive performance, udder health, dental health, body condition score and breeding of ewe lambs, are reviewed. Finally, current knowledge gaps and future areas of research are identified and evaluated.

Aims: To gather data on the calf management and rearing practices of a subset of dairy farmers in the south-west region of Western Australia.

Methods: A 30-minute face-to-face survey was conducted with dairy cattle producers in the south-west region of Western Australia from April-June 2019 to determine pre-weaning calf rearing practices. Participation was voluntary, using a self-selected subset of dairy farmers registered with a regional extension group. The questionnaire assessed three broad categories: farm demographics, colostrum harvesting and management and calf rearing practices.

Results: The study response rate was 34/140 (24%). The following key areas were identified where there were deviations from recognised best practice: Precalving: no transition diet was fed pre-calving on 4/34 (12%) of farms, and on a further 5/34 (15%) it was fed for less than 3 weeks; mixing of heifers and adult cows in the calving paddocks occurred in 24/34 (70%) of the farms, with 15% (5/34) of the farms using calving induction. During calving 14/34 (41%) of the farms did not disinfect navels of new-born calves; although 23/34 farmers stated that they collected calves within 6 hours of birth, data on frequency of calf pick-up (2/34 did not separate calves and dams and 19/34 picked up only once per day) indicated that on 21/34 farms (62%) the reality was that calves were picked up >12 hours after birth. Colostrum quality was not assessed appropriately on 18/34 (53%) farms and farmers overestimated how soon after birth it was administered: 23/34 (68%) reported feeding it within 6 hours of calving, despite 62% picking up calves >12 hours after calving. Regarding calf rearing practices, no pain relief before or after dehorning was used on 20/34 (59%) farms, calf bedding was removed infrequently (

Conclusion and clinical relevance: Although limited by the low response rate, this is the first survey of dairy calf rearing practices in the south-western region of Western Australia. We found evidence of at least one process inconsistent with industry best-practice on 34/140 (24%) of responding farms and all farms had more than one sub-optimal calf rearing practice. This highlights the need to improve calf rearing in this region and identifies key areas of deficiency for further study and extension to producers.