Leptospirosis in a lamb

Abstract

Extract

Recently, we reported on outbreaks of Leptospira interrogans serovar pomona infection in newly weaned lambs(1) Vermunt, JJ, West, DM, Cooke, MM, Alley, MR and Collins-Emerson, J. 1994. Observations on three outbreaks of Leptospira interrogans serovar pomona infection in lambs. New Zealand Veterinary Journal, 42: 133–6. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]. It was suggested that wet environmental conditions played an important role in the pathogenesis of the disease in that class of sheep. This communication presents observations on another case of ovine leptospirosis, one that occurred under different circumstances, i.e. different season, age and environmental conditions.     

A study of naturally occurring cases of ovine foot abscess in New Zealand

A study was made of various aspects of 53 naturally occurring cases of foot abscess in sheep in New Zealand. Radiographic techniques were used to follow the progress of the lesion and from this it was concluded that foot abscess could be defined as an infection of the distal interphalangeal joint. The term “foot abscess” was considered preferable to the term “infective bulbar necrosis”.

The attack rate of foot abscess was reported to be higher for rams than for ewes and the condition was less prevalent during summer.

Once infection was established in the distal interphalangeal joint a relatively uniform and thus predictable series of events took place that inevitably resulted in some permanent damage and deformity to the digit. If rupture of the axial collateral ligaments occurred, the joint became unstable and the de- gree of permanent deformity was greater. Treatment with antibiotics did not appear to markedly affect the progress of the lesion or the outcome, once infection had become established in the joint.

Although the prognosis for complete recovery was poor, in most cases the foot healed sufficiently after a period of about two months to allow the animal to walk normally.     

Salmonellosis in sheep and zinc oxide dosing–a reply from massey university

Extract

Madam:– We are surprised that Messrs Smith and Towers misinterpreted our letter on salmonellosis in ram hoggets following prophylactic zinc dosing as a criticism of their actions or of their research and publication record. In fact, they echo our caution in stating that the results of drenching sheep with a fortnight's accumulated dose of zinc oxide have been presented and discussed as preliminary and that "no final recommendations will be made until optional dose rates and safety factors have been assessed."     

The impact of highly concentrated Mo and Cu dietary supplements,fed as a bolus,on the efficacy of chelated versus inorganic Cu in cattle on a low-Cu diet

AIM: To compare the efficacy of chelated versus inorganic forms of dietary Cu supplements, fed as a bolus, when challenged by a daily bolus of dietary Mo in cattle on a low-Cu diet.

METHODS: Forty non-lactating, Friesian dairy cows of adequate Cu status were assigned to four groups and fed a basal diet of baled silage containing 5.3 mg Cu and 0.4 mg Mo/kg DM. The experimental design was a factorial of two chemical forms of supplemental Cu and two levels of Mo intake, provided as pelleted grain supplements made from crushed barley/molasses plus Cu and Mo. The supplements contained 140 mg Cu/kg as Cu sulphate pentahydrate (CS), 140 mg Cu/kg as Cu glycinate (CG), CS plus 38 mg Mo/kg as sodium molybdate (CS+Mo), or CG plus 38 mg Mo/kg (CG+Mo). Commencing on Day 0, supplements were fed once daily (offered 1–1.2 kg/cow) and were completely consumed within 5–10 minutes, which constitutes a bolus type of administration. Liver samples were collected by biopsy at Days ?24, 13, 41 or 47, and 69 for Cu determinations.

RESULTS: The diets fed to the Cu+Mo groups were roughly equivalent to 25 mg Cu and 5.7 mg Mo/kg DM. Mean initial concentration of Cu in liver for all groups was 516 (SE 54) μmol Cu/kg fresh tissue. In cows supplemented with CS and CG, the final (Day 69) concentrations increased (p<0.01) to 939 (SE 166) and 853 (SE 163) μmol Cu/kg, respectively. These values were not different (p=0.72). For groups CS+Mo and CG+Mo, the final concentrations of 535 (SE 122) and 453 (SE 102) μmol Cu/kg were not different from initial values or from each other (p>0.25). The rate of accumulation of Cu in liver following bolus Cu and Mo intake was highly variable but was not affected by initial concentration of Cu in liver (p>0.9) or by the form of Cu (p>0.6). Mean rates of accumulation of Cu in liver were 4.0 (SD 3.8) and 0.65 (SD 2.0) μmol Cu/kg fresh tissue/day for the Cu-only treatments and the Cu+Mo treatments, respectively.

CONCLUSIONS: When fed together as a bolus, high Mo intake negated the effect of supplemental Cu but it did not reduce liver Cu stores. There was no difference in the reaction of dietary Mo with chelated Cu (as glycinate) versus inorganic Cu (as sulphate) dietary supplements.     

The response of vaccinated rams to experimental challenge using Brucella ovis

One hundred and thirty eight rams were allocated to four experimental groups. An inactivated Br. ovis vaccine was administered either once by the intraperitoneal route (1 i/p), twice by the intraperitoneal route (2 i/p), or twice by the subcutaneous route (2 s/c), and the last group was left unvaccinated. They were then challenged by the intravenous inoculation of between 123 and 1.23 × 10⁸ live Br. ovis bacteria. The number of rams that succumbed to infection within the four groups was 4/35 (11%) for the 2 s/c, 7/33 (21%) for the 2 i/p, 9/35 (26%) for the 1 i/p and 18/35 (51%) for the unvaccinated rams. Vaccination reduced the number of rams that succumbed to experimental challenge and although there were differences between the vaccinated groups, these were not statistically significant.

Following challenge, unvaccinated rams were the first to excrete Br. ovis in their semen; three weeks following inoculation. Next, those vaccinated by either one or two doses by the intraperitoneal technique began to excrete the organism (five weeks) and then finally those rams vaccinated twice by the subcutaneous route (seven weeks).     

Oestrogen,Progesterone and Oxytocin Receptors and COX‐2 Expression in Endometrial Biopsy Samples from the Induction of Ovulation to Luteolysis in Llamas (Lama glama)

Endometrial expression of oestrogen (ERα), progesterone (PR) and oxytocin receptor (OR) and cyclooxygenase‐2 (COX‐2) was evaluated from the induction of ovulation to luteolysis in llamas. Ovarian activity was daily assessed by ultrasonography in five females. Ovulation was induced immediately after the detection of an ovulatory follicle by a GnRH injection (Day 0). Endometrial samples were obtained by transcervical biopsies from the left and right horns on day 0 and days 4, 8, 10 and 12 post‐GnRH. Blood samples were collected daily for progesterone and estradiol‐17β determinations by RIA. An immunohistochemical technique was used to study receptors population and COX‐2 expression which were then evaluated by two independent observers. The expression of ERα and PR was highest on day 0 in the luminal epithelium and stroma in association with high plasma estradiol‐17β concentrations. Thereafter, a decrease in ERα population was registered on day 4 and a new increase of its expression was observed between days 8 and 12 in those cell types. Conversely, PR population was gradually down‐regulated until its lowest expression was reached on day 10 post‐GnRH in the luminal epithelium. Content of OR was similar throughout the study in all cell types. The expression of COX‐2 was highest from day 8 to 12 post‐GnRH in the luminal epithelium, in relation to the time of maximal PGF_2α release. Both steroid receptors populations and COX‐2 expression were similar between horns. Meanwhile, OR expression was higher in the right than in the left uterine horn. In summary, this study showed that the loss of endometrium sensitivity to progesterone by days 8–10 post‐induction of ovulation and the concomitant increase of COX‐2 expression could play a key role in the mechanism of luteolysis and somehow be related to the short corpus luteum lifespan of llamas.     

A case of "watery mouth" in a New Zealand Romney lamb

Watery mouth was diagnosed as the cause of illness and subsequent death in a 3-day-old Romney lamb which had not received early colostrum. The history, clinical signs and post-mortem findings were typical of the disease as seen in other countries, including Great Britain. The diagnosis was based on the clinical signs and was supported by an absence of post-mortem findings of other specific neonatal diseases. The potential importance of watery mouth under conditions of intensive husbandry in New Zealand is discussed.     

The effect of breeding ewe lambs on subsequent two-year-old ewe performance

This study was undertaken to determine if breeding ewe lambs (hoggets) would influence subsequent two-year-old (two-tooth) ewe liveweight and reproductive performance and their lamb's performance to weaning. Two-tooth Romney ewes that had been bred and lambed as a hogget (n = 505) were compared with those of 196 ewes that were bred as a hogget but did not lamb and 235 ewes that were not presented for breeding as a hogget. Hogget lambing resulted in reduced (P < 0.05) two-tooth liveweight and body condition score at breeding although still present this liveweight difference was reduced by two-tooth lamb weaning. Two-tooth ewes that had previously lambed as a hogget had greater (P < 0.05) returns to service rates and lower (P < 0.05) fecundity (multiple-bearing/two-tooth bred) than those that were bred for the first time. Two-tooth lamb liveweights were unaffected by hogget lambing. These results show that hogget lambing had a small negative effect on subsequent two-tooth reproductive performance. This was most likely caused by reduced liveweight at two-tooth breeding and indicates that farmers need to ensure management practices are in place to reduce the impact of hogget lambing on two-tooth liveweight.