The relationship between the prevalence of uterine lesions and the use of medroxyprogesterone acetate for canine population control

SUMMARY The prevalence of uterine disease was established during desexing of 175 bitches in the Torres Strait and Cape York, 42 of which had been treated with injectable medroxyprogesterone acetate (MPA) for oestrus postponement. The prevalence of uterine lesions was 45% for treated bitches, 5% for untreated bitches, and 14.9% for the sample population. A highly significant relationship (P<0.01) between MPA treatment and uterine lesions was established. A significant association (P<0.05) between age (>2 years old) and uterine lesions was found, most likely attributable to a significantly higher proportion (P<0.01) of MPA-treated bitches in the older population. There was no significant difference in the effect of MPA on the prevalence of uterine lesions between older and younger bitches. There was no effect of parity on the prevalence of uterine lesions.     

The effect of delays in feeding colostrum and the relationship between immunoglobulin concentration in the serum of neonatal calves and their rates of growth

SUMMARY Eighty-five unsuckled newborn calves, were fed 1.5 L of colostrum of known IgG concentration at either 2, 4, 6 or 8 hours after birth with no additional colostrum feeding. Another group of 11 calves were left with their dam for 16 hours after birth, before separation. Blood samples were taken from all calves 24 hours after colostrum feeding or separation from the dam and serum Ig concentrations were measured by electrophoresis. There were no significant differences in mean serum Ig concentrations between calves fed at the different times after birth. Three of the 11 calves left to suckle were hypogamma-globulinaemic. Other calves in this group had higher serum Ig concentrations than the means of all other groups. All groups had mean serum Ig concentrations higher than the suggested minimum concentration required for adequate calf health. There were a number of calves that did not reach the suggested minimum serum concentration after feeding, but calf mortality was low and all calves were healthy apart from a slight scour for a few weeks after birth. There was no significant relationship between serum Ig concentration 24 to 48 hours after birth and either calf mortality or average growth rate over an 8- to 10-month period.     

Cerebellar abiotrophy in crossbred cattle

Cerebellar abiotrophy affected 9 of 74 calves sired by a Poll Hereford bull over 2 successive calving seasons. The disease was characterised by episodes of recumbency and ataxia, with hypermetria and wide base stance. Clinical signs commenced between birth and 8 months of age. Two calves which were affected first at 8 months of age recovered clinically 9 months later. Histological lesions were found in the cerebellar cortex of 7 calves and consisted of segmental degeneration and loss of Purkinje cells, and axonal swellings. The clinical signs and pathological findings were consistent with bovine familial convulsions and ataxia, which has not been described previously in Australia. The clinical signs were not attributable to the lesions observed in the cerebellum and an underlying electrophysiological abnormality is proposed. The aetiology of the condition is probably genetic and appears to have a multifactorial basis.     

The development and integrity of equine pre‐antral follicles cultured in vitro with follicle‐stimulating hormone (FSH) supplementation

This study investigated the effects of different concentrations of FSH (10, 50, 100 and 200 ng/ml) in supplemented MEM+ on the development of equine pre‐antral follicles that were cultured in vitro for 2 or 6 days. The ovaries (n = 5) from mares in seasonal anoestrus were collected from a local abattoir. Ten ovarian tissue fragments of approximately 3 × 3 × 1 mm were obtained from each animal. The fragments were cultured in situ for 2 days (D2) or 6 days (D6) in MEM+ or MEM+ supplemented with FSH at four different concentrations, establishing the following 11 groups: control (D0); MEM + (D2); MEM + (D6); MEM + 10 ng/ml of FSH (D2); MEM + 10 ng/ml of FSH (D6); MEM + 50 ng/ml of FSH (D2); MEM + 50 ng/ml of FSH (D6); MEM + 100 ng/ml of FSH (D2); MEM + 100 ng/ml of FSH (D6); MEM + 200 ng/ml of FSH (D2); and MEM + 200 ng/ml of FSH (D6). Follicles were observed in only 9.65% (388 of 4,018) of the histological sections. Of the 861 follicles evaluated, 488 were in the primordial stage, and 373 were in various developmental stages; 59.7% were morphologically normal. Regarding the integrity of the pre‐antral follicles, the groups with 100 ng/ml FSH of 2‐days culture as well as 50, 100 and 200 ng/ml FSH of 6‐days culture provided the best results. In conclusion, the in vitro culture of abattoir‐derived equine ovarian fragments presented better morphological integrity when supplemented with FSH for 6 days, in comparison with the MEM culture group. However, no clear effects were observed with FSH regarding the promotion of activation from a primordial to a developing follicle.     

An in situ single-pass perfusion model for assessing absorption across the intestinal mucosa of the brushtail possum

AIM: To develop an in situ animal model for assessing absorption of molecules across the intestinal mucosa of possums.

METHODS: A surgical preparation was used to perfuse known concentrations of reference compounds (fluorescein and luteinising hormone-releasing hormone; LHRH) through measured sections of selected regions (jejunum, caecum, proximal colon) of the intestinal tract of 19 possums, over a 2-h period. Plasma concentrations of the compounds, which were perfused either with or without co-administration of a permeation enhancer (sodium deoxycholic acid; SDA), were determined in the perfusion effluent, peripheral and in some instances in the pre-hepatic circulation by spectrofluorometry (fluorescein) or radio-immunoassay (LHRH). Pharmacokinetic parameters of both compounds in the possum were determined over a period of up to 4 h in a further 30 animals (fluorescein, n=6; LHRH n=24), from their plasma profiles following intravenous (I/V) administration of a bolus dose.

RESULTS: In animals perfused with 25 mg/ml fluorescein (Perfusion Experiment (PE) 1), the mean plasma concentration was 2.8 (SE 0.12) µg/ml in post-hepatic blood samples. When possums were perfused with 2.5 mg/ml fluorescein and 7 µg/ml LHRH (PE 2), mean plasma concentrations were 0.3 (SE 0.01) and 7.8 (SE 1.64) µg/ml fluorescein and 0.1 (SE 0.02) and 6.3 (SE 0.45) ng/ml LHRH, in the absence and presence of permeation enhancer, respectively. There was a poor correlation between pre-hepatic and post-hepatic concentrations.

CONCLUSIONS: The single-pass in situ perfusion technique provided a useful model for investigating basic information on the absorption of biocontrol agents across the intestinal tract of possums, but had limitations that must be recognised.     

Preliminary investigation of the effect of treating sheep during pregnancy with a vitamin A,D, E formulation on the incidence of vaginal prolapse

ABSTRACT

Aim: To determine if vitamin D₃ treatment reduced the incidence of vaginal prolapse in pregnant sheep on a North Canterbury sheep breeding property.

Methods: Pregnant ewes from a single farm were allocated to three treatment groups in May 2018. At this time, the first group (EarlyVitADE; n?=?512) received an I/M 1?mL dose of 500,000?IU/mL vitamin D₃, 60,000?IU/mL vitamin A, and 25?mg/mL vitamin E. This was repeated in July 2018, when the second group (LateVitADE; n?=?695) also received the same treatment. The third group (n?=?737) were untreated controls. All cases of vaginal prolapse on the property were recorded from pregnancy diagnosis in June 2018 until ewes were set-stocked in August 2018. The planned start of lambing was 10 August 2018.

Results: During the period of observation, vaginal prolapses were recorded in 3/699 (0.4%) 2-year-old ewes, and the odds of vaginal prolapse were not associated with treatment group in these ewes (p?>?0.3). Amongst ewes aged ≥3 years, during the same period, there were 6/333 (1.8%), 6/443 (1.4%) and 25/469 (5.3%) cases in the EarlyVitADE, LateVitADE and control groups, respectively. Compared to control ewes, the odds of vaginal prolapse were reduced in both the EarlyVitADE (OR?=?0.37; 95% CI?=?0.15–0.92) and LateVitADE (OR?=?0.25; 95% CI?=?0.10–0.62) treatment groups.

Conclusions and clinical relevance: In this preliminary study, administration of injectable vitamins A, D₃, and E to pregnant ewes reduced the incidence of vaginal prolapse during the period from pregnancy diagnosis to set-stocking on one North Canterbury hill-country farm. Due to the restricted data collection period, this investigation should be replicated to better quantify the repeatability of the observed treatment effect over the complete lambing period.     

Assessment of Progesterone Concentration Using Enzymeimmunoassay, for Early Pregnancy Diagnosis in Sheep and Goats

The objective of this study was to determine a value of serum progesterone (P₄) concentration, assessed using an enzymeimmunoassay (EIA), for the early distinction between pregnant and non‐pregnant ewes and goats. Adult, non‐lactating ewes of Chios (n=53), Berrichon (n=30) and Sfakia (n=45) breeds were synchronized during the breeding season with progestagens and gonadotrophins and mated to fertile rams (Experiment I). Adult, lactating goats of Swiss breeds (Alpine and Saanen, n=104) and indigenous Greek breed (n=45) were synchronized during the transitional season with progestagens, PGF₂α and gonadotrophins. Cervical artificial insemination (AI) with fresh semen was applied once, 42–44 h after sponge removal (Experiment II). Jugular blood samples were collected on day 19 after sponge removal (ewes) or on day 21 after AI (goats) and serum P₄ concentration was determined by EIA. Progesterone concentrations ≥1.0, ≥1.5, ≥2.5 and ≥4.0 ng/ml were tested as indicative of pregnancy. Pregnancy diagnosis was verified on birth. In the case of sheep, using a discriminatory level of 2.5 ng/ml, overall accuracy of pregnancy diagnosis was 91.4% and predictive value of negative and positive diagnoses were 98.3 and 85.3%, respectively. In the case of goats, predictive value of negative diagnosis was 95.8 and 94.0% and predictive value of positive diagnosis 71.3 and 71.7%, for 1.5 and 2.5 ng/ml, respectively; overall accuracy was 79.2% using either level. The other discriminatory levels tested did not improve these results. A significant positive correlation was observed between P₄ concentration and the number of lambs or kids born, and further analysis indicated that this relationship is not a simple linear function. Based on the results of this study, P₄ concentrations of 2.5 ng/ml in the case of ewes and 1.5–2.5 ng/ml in the case of goats, determined with EIA, are proposed as discriminatory levels between pregnant and non‐pregnant animals, at an interval of one oestrous cycle after service.     

An isolation of Leptospira serotype Pomona from a domestic cat

Extract

Between November 1971 and July 1972, the gastro-intestinal tracts of 51 dogs and 47 cats of various age were examined for helminth parasites. The animals examined were unselected and had been submitted for autopsy following death from causes unrelated to parasitism. Most of the animals were pets, but included in the survey were some working dogs. All came either from the city of Palmerston North or its surrounding rural areas.