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.     

Some aspects of the epidemiology of equine salmonellosis

A survey of 2 horse populations was done to detect the number of asymptomatic faecal excretors of Salmonella sp. 1201 faecal samples from 250 horses hospitalised at the University of Sydney were cultured. Three serotypes, S. typhimurium (4 horses), S. anatum (2) and S. tennessee (1) were isolated from 7 horses (2.8%). None was detected in 75 mares similarly examined at a thoroughbred stud farm. In retrospect, S. typhimurium was also the most common (70%) of the 19 serotypes recovered from 171 horses with clinical salmonellosis seen at Camden, 1969 to 1986. Forty cases occurring since 1983 were reviewed in detail; the mortality rate was high (60%) and an increased proportion was due to S. bovis-morbificans. Five horses developed salmonellosis while hospitalised and it was usually impossible to be certain whether these cases developed from the carrier state into overt disease or resulted from infections acquired in hospital.     

The importation of the black rhinoceros (Diceros bicornis) from Zimbabwe into Australia

SUMMARY The paper describes a program to import and breed black rhinoceros ex situ at Western Plains Zoo in Australia. Nine rhinoceros (7 females and 2 males) captured in 1992 in Chete National Park, Zimbabwe, were transported to Australia via Cocos Island. The veterinary treatment of the animals before and during quarantine in Zimbabwe and on Cocos (Keeling) Islands is described. Three animals died; an adult male on Cocos Islands and a juvenile male and an adult female at Western Plains Zoo, Dubbo, New South Wales. The juvenile male died as a result of trauma sustained shortly after arrival and the two adults after developing a severe hepatopathy. The group of 6 females and an additional 4 males imported from the USA in 1994 have adapted well to captivity and to the climate and environment of central west New South Wales.     

Investigation of the index case herd and identification of the genotypes of Theileria orientalis associated with outbreaks of bovine anaemia in New Zealand in 2012

CASE HISTORY AND CLINICAL FINDINGS: On 7 September 2012 the Ministry for Primary Industries was notified of a dairy cow with regenerative anaemia (haematocrit (HCT) 0.08?L/L) in a herd of 465 Jersey-Friesian cross cows (index case herd) in the Northland region of New Zealand. Organisms consistent with Theileria spp. were present in red blood cells on a blood smear. No other causes of anaemia were detected following examination of affected cows. Blood samples collected from 29 randomly selected cows on 26 September 2012 showed that 24 (83%) were anaemic (HCT≤0.24 L/L) and therefore fitted the case definition for bovine anaemia associated with Theileria orientalis infection.

LABORATORY FINDINGS: Using a T. orientalis type-specific PCR assay that targeted the single subunit rRNA gene, all of six animals tested were positive for T. orientalis type Ikeda. Blood samples collected from clinically affected cattle in 11 subsequent outbreaks from throughout the North Island showed that T. orientalis Ikeda type was a common finding, but mixed infections with Chitose type were also identified. In addition, using a PCR assay that targeted the major piroplasm surface gene, T. orientalis type 5 was detected in one cow from the Waikato region.

DIAGNOSIS: The presence of T. orientalis type Ikeda, as well as type 5, was confirmed in cattle from outbreaks of bovine anaemia in herds throughout the North Island of New Zealand.

CLINICAL RELEVANCE: Two new types of T. orientalis were identified in this investigation, that were associated with a sudden rise in cases of bovine anaemia. The body of evidence showed that the Ikeda type was implicated as the cause of disease observed in this epidemic.     

Effects of local anaesthesia of 4 to 8 hours duration on the acute cortisol response to scoop dehorning in calves

Objective To determine the effect of a long-acting local anaesthetic on the plasma cortisol response in calves dehorned using a scoop.
Design A physiological study with controls.
Procedure Seventy female calves, 3 to 4 months old, were divided into seven groups and dehorned by scoop with or without a long acting local anaesthetic (bupivacaine) which provides local anaesthesia for 3 to 4 h. In some treatment groups the local anaesthetic was given a second time, after 4 h, to give 8 h of anaesthesia. Blood samples were taken before and for 9 h after treatment and plasma cortisol concentrations were measured.
Results Scoop dehorning caused a marked rise in plasma cortisol concentration, which returned to pre-dehorning values after 7 h. The cortisol concentrations of calves given bupiva-caine were similar to those of control animals for 4 h after dehorning, but then a significant and protracted rise occurred, with concentrations returning to pretreatment values at about 9 h after dehorning. In calves given a second treatment of bupivacaine 4 h after dehorning, the plasma cortisol concentration remained similar to control values for 8 h after dehorning but then increased sharply.
Conclusions During its period of activity long-acting local anaesthetic prevented the rise usually seen after scoop dehorning in plasma cortisol concentrations; by inference it also alleviated the pain-induced distress caused by this procedure. However, when its effects had worn off the plasma cortisol values rose sharply indicating that animals still experienced pain-induced distress despite local anaesthetic being administered.     

Luteolytic Effect of Prostaglandin F2α on Bovine Corpus Luteum Depends on Cell Composition and Contact

Prostaglandin F_2α (PGF_2α) is a main luteolytic factor in vivo; however, its direct luteolytic influence on steroidogenic cells of bovine corpus luteum (CL) is controversial and not fully understood. The aim of the study was to clarify PGF_2α action on bovine CL in different in vivo and in vitro conditions and to examine whether the contact among all main types of CL cells is necessary for luteolytic PGF_2α action. In experiment 1, the bovine CL (day 15 of the oestrous cycle) was perfused using in vivo microdialysis system with dinoprost (an analogue of PGF_2α) for 0.5 h. Dinoprost caused a short‐time increase in progesterone (P4), whose concentration decreased thereafter (at 6‐, 10‐, 12‐ and 24‐h after treatment). In experiment 2, the direct effect of PGF_2α on P4 accumulation in CL steroidogenic cells cultured in monolayer (day 15 of the cycle) was determined. PGF_2α after 24 h of incubation increased P4 accumulation in steroidogenic CL cells. In experiment 3 steroidogenic, endothelial CL and immune cells (day 15 of the cycle) were incubated with PGF_2α in cocultures for 24 h in glass tubes and the levels of P4, stable metabolites of nitric oxide (NO) and leukotriene (LT) C₄ were determined. Although PGF_2α treatment increased P4 secretion in homogeneous steroidogenic CL cell culture, the decrease in P4 secretion in cocultures of all types of CL cells was observed. The secretion of NO and LTC₄ increased after the treatment of PGF_2α both in pure cultures of CL cells and in cocultures. The interactions between endothelial and immune cells with steroidogenic CL cells are needed for luteolytic PGF_2α action within the bovine CL. Our results indicate that the cell coculture model, including the main types of CL cells, is the most approximate to study PGF_2α role in vitro.