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The cause of ill thrift and deaths was investigated in a group of 40 Scottish lowground ewes, which had been treated with levamisole and then turned onto clean grazing after lambing, 6-8 weeks previously. Concurrent haemonchosis and teladorsagiosis were diagnosed, putatively associated with the spring maturation of large numbers of hypobiotic larvae. Ill thrift due to parasitic gastroenteritis consequently occurred in the lambs which had been turned onto the 'clean' grazing with their dams, despite metaphylactic anthelmintic treatments. The contributory role of haemonchosis resulting in serious production-limiting disease is unusual in Scottish sheep flocks. It is suggested that the problem may have arisen as a consequence of the adaptation of Haemonchus contortus to survive overwinter in a cold climate as arrested early fourth stage larvae, which were not eliminated when the ewes were treated with levamisole at turnout.

Multiple resistance to benzimidazole, imidazothiazole and macrocyclic lactone anthelmintics is an emerging problem in the south-east of Scotland. The general management and nematode control strategies employed in four affected flocks (flocks 1-4) were investigated in an attempt to identify the risk factors which might have led to the appearance of production limiting disease associated with anthelmintic resistance. The important risk factors for multiple anthelmintic resistance could not be confirmed and it proved easier to criticise nematode control practices on theoretical grounds, than to propose practical solutions. It seems likely that different risk factors were involved in the four flocks. Lambs in flocks 1 and 2 had been treated with an anthelmintic at 3-4 weekly intervals with the aim of achieving suppressive nematode control, while sheep in flock 1 had been treated with an anthelmintic after they were moved onto clean grazing. Recently lambed ewes had been treated with moxidectin in three of the four flocks, with the aim of controlling their periparturient rise in faecal nematode egg output. All of these factors might have contributed to the emergence of multiple anthelmintic resistance, because they could have led to anthelmintic treatments at times when the nematode population in refugia was small, compared to that in the sheep. Annual rotation of the anthelmintic group was compromised by the emergence of benzimidazole resistance and did not prevent the emergence of multiple resistance in any of the flocks described, although the practice may have slowed the development of resistance. Underdosing may have selected for benzimidazole and imidazothiazole resistance in flock 2, associated with inaccurate estimation of the weights of terminal sire lambs. These investigations also highlighted problems associated with the diagnosis of anthelmintic resistance, in particular the confounding effects of the onset of host immunity to nematode parasites, the possible influence of the age of the adult nematode population, and the insensitivity of the undifferentiated faecal egg count reduction test in situations where resistance is emerging.

Forty multigravid ewes with naturally-occurring ovine pregnancy toxaemia were treated with a concentrated oral dextrose and electrolyte solution administered three times daily an oral and a single subcutaneous injection of either a slow release formulation of 160mg recombinant bovine somatotropin (n = 17) or placebo injection (n = 23). A higher recovery rate was achieved in ewes treated with 160mg recombinant bovine somatotropin compared with controls (58.8 versus 34.8%, respectively), and more lambs were born alive and survived to 24th from treated ewes (15 of 46 lambs; 32.6%) compared with control ewes (12 of 62 lambs; 19.4%) but the treatment effects were not significantly different from the control group (P > 0.05).

The feasibility of breeding spring-calving, single-suckled beef cows without the use of natural service was investigated over two breeding seasons by using repeated oestrus synchrony and fixed-time artificial insemination (AI). Initially, cows were oestrus-synchronised with subcutaneous norgestomet implants inserted for 10 days, with an injection of prostaglandin before the implants were removed. The cows were inseminated once 56 hours after the implants were removed, and 12 days later they were re-treated with norgestomet implants to allow a second synchronised service. Twenty-one days after the first synchronised AI, milk samples were taken for progesterone assay and the norgestomet implants were removed. The cows received a second service 56 hours later if the 21-day milk progesterone assay suggested that they were not pregnant. All the cows receiving a second service were retreated with norgestomet implants to allow a third synchronised service as necessary. Pregnancy was later confirmed by rectal palpation. In the first year, 48 cows entered the programme and the pregnancy rates to the first, second and third synchronised services were 56, 69 and 40 per cent, respectively, with 17 per cent of cows barren at the end of the breeding period. In the second year, 69 cows entered the programme and the pregnancy rates were 58, 48 and 33 per cent to the successive services with 20 per cent of cows barren at the end of the breeding period. The accuracy of milk progesterone assay for pregnancy diagnosis was 84 per cent and 87 per cent in the first and second years, respectively.

Two days after being imported into the United Kingdom one of a group of 30 pregnant dairy heifers showed clinical signs of bovine viral diarrhoea virus (BVDV) infection and subsequently died. Before it died the heifer was BVDV antigen-positive and antibody-negative. The gross post mortem findings were suggestive of mucosal disease but in addition to noncytopathic BVD virus, Salmonella typhimurium DT104 was cultured from tissues and gut contents. The other heifers were screened for S typhimurium by culturing faeces, and serology showed that 13 (45 per cent) of the group seroconverted to BVDV in the three weeks between samplings and the remainder were seropositive, indicating previous exposure. During this period four heifers showed clinical signs of acute BVDV infection but recovered uneventfully. Four animals (14 per cent) were positive for S typhimurium DT104 on faecal culture, and three of these excretors concurrently seroconverted to BVDV. Of the 29 heifers remaining in the group, one aborted in late gestation, 26 bore live calves and two delivered stillborn calves. Pre-colostral blood samples from the calves showed that their dams' pre-existing antibody titres correlated well with in utero fetal protection. In non-immune dams, exposure to BVDV between 69 and 120 days of gestation led to the birth of live persistently viraemic calves. Infection between 120 and 140 days of gestation led to the birth of live calves with evidence of congenital damage to the central nervous system, and infection later than 140 days of gestation led to the birth of live, normal calves with high pre-colostral antibody titres to BVDV. One calf which sucked colostrum was antibody and virus antigen-positive when sampled at 12 hours old but regular blood sampling failed to detect viraemia again until the calf was seven weeks old when it became persistently viraemic.

Severe respiratory disease, associated with seroconversion to bovine respiratory syncitial virus (BRSV), caused the death of two cattle and necessitated antibiotic treatment of 70 calves (rectal temperature of 39.6 degrees C or greater) from a group of 96 (73%) during an 8-day period. Tilmicosin injection resulted in a reduction in median rectal temperature from 40.3 degrees C to 39.2 degrees C and 39.0 degrees C for the first and second days after treatment. The rectal temperature was 39.5 degrees C or lower in 72% (48 of 67) and 96% (64 of 67) of cattle 1 and 2 days after tilmicosin treatment, respectively. Ten cattle were re-treated with tilmicosin 6 to 16 days after the first treatment. Our study demonstrated that bovine respiratory syncytial virus infection could cause severe respiratory disease in a beef herd that had no previous history of BRSV-related disease. Secondary bacterial invasion after BRSV infection was controlled effectively by tilmicosin treatment but repeat antibiotic treatments were occasionally necessary due to bacterial re-infection of the respiratory tract.

Twin and single pregnancies were induced in two groups of oestrus-synchronised beef cows by using a combination of artificial insemination and the transfer of in vitro fertilised (IVF) embryos. Single IVF embryos transferred non-surgically to the uterine horn contralateral to the corpus luteum of 43 previously inseminated cows resulted in a calving rate of 72 per cent with a twinning rate of 38.7 per cent. In 45 cows, two IVF embryos were transferred non-surgically to one uterine horn resulting in a calving rate of 51.1 per cent with a twinning rate of 39.1 per cent. The median gestation length for cows bearing twins was 10 days shorter than that of cows bearing single calves (P < 0.001). The proportions of cows that received assistance at calving were similar for twin and single births (57 per cent vs 45 per cent, P > 0.05), but the incidence of retained fetal membranes was much higher after the birth of twins (62 per cent vs 3 per cent, P < 0.001). Nineteen per cent of twin calves were stillborn compared with 6 per cent of single calves (P > 0.05). The median birthweight of the twin calves was 32 kg (68 per cent of the median weight of single calves). The nutrition of twin-bearing cows in late pregnancy was adequate when assessed in terms of their plasma glucose, non-esterified fatty acid and beta-hydroxybutyrate concentrations. Serum immunoglobulin concentrations were similar in single and twin calves suggesting that the passive transfer of antibody was not compromised in the twin calves.

Two millilitres of solution calculated to contain 0.07 mg/kg xylazine and 0.5 mg/kg lignocaine injected at the sacrococcygeal epidural site provided caudal analgesia within 2 min in 61 sheep. This analgesic protocol eliminated forceful abdominal straining behavior following replacement of vaginal prolapse for at least 24 h in 48 of 52 ewes (92%) and in all 9 ewes with uterine prolapse. Moderate pelvic limb ataxia was observed in 25 sheep (41%) for up to 24 h after epidural injection. Sedation was noted in one ewe but no other systemic effects of xylazine injection, such as excessive salivation or ruminal distension, were observed. No long-term adverse reactions to xylazine injection were noted. The combined epidural injection regimen of xylazine and lignocaine is recommended as an adjunct for pain relief and control of abdominal straining following replacement of vaginal and uterine prolapse in ewes.

A naturally occurring outbreak of sheep scab in a flock of 202 ewes during mid-pregnancy resulted in exudation from the scab lesions and hypoalbuminaemia lasting for two to 10 weeks in the severely affected ewes. The serum albumin concentration at the time of diagnosis and two weeks after treatment with ivermectin was inversely correlated with the severity of the scab lesions (P < 0.001). The loss of body condition score over a period of 48 days after treatment was significantly correlated with the initial severity of the scab lesions (P < 0.001). Despite adequate energy nutrition of the ewes during late pregnancy, the birthweights of lambs born to ewes with severe sheep scab were 10 per cent less than those of lambs born to ewes with mild sheep scab.

An outbreak of naturally occurring sheep scab in a flock of 207 sheep was successfully treated with three consecutive weekly subcutaneous injections of ivermectin at a dose rate of 200 micrograms/kg. Plunge dipping ewes during early pregnancy was not considered appropriate on welfare grounds.

Large subcutaneous fluid swellings developed on some of the sheep in two flocks infested with Psoroptes ovis during the two weeks after they had been plunge-dipped in phenol-based solutions. The swellings contained between 1 and 10 litres of exudate and affected 4 per cent of the sheep in each flock. The sheep with subcutaneous fluid swellings or exudative dermatitis had significantly lower serum albumin concentrations than the unaffected sheep (P < 0.05). In most cases secondary bacterial infections of the exudate occurred and these necessitated intensive antibiotic therapy. The severity of the skin lesions posed a serious welfare problem.

Cerebrospinal fluid (CSF) and plasma glucose concentrations of spontaneous ovine pregnancy toxaemia cases, determined within 24 h of the onset of clinical signs, were significantly lower (P < 0.01) compared to inappetant ewes and healthy ewes at a similar stage of gestation. A highly significant correlation (P < 0.001, r = 0.91) was present between the plasma and CSF glucose concentrations when the data from the three groups were combined. The data suggest that plasma glucose concentration accurately reflects CSF glucose concentration across the range of energy states in pregnant ewes and may provide support for the postulate that the neurological signs of ovine pregnancy toxaemia result from cerebral hypoglycaemia, as reflected by CSF glucose concentration. No cerebral glucose estimations were undertaken in this series.

Bacterial meningoencephalitis most commonly affected lambs two to four weeks old (median three weeks, range three days to six months) with clinical signs of episcleral congestion, lack of suck reflex, weakness, altered gait and depression extending to stupor, but hyperaesthesia to auditory and tactile stimuli. Opisthotonos was observed during the agonal stages of the disease. Analysis of lumbosacral cerebrospinal fluid revealed a highly significant increase in protein concentration (P < 0.01) with a neutrophilic pleocytosis, but bacteriological culture yielded organisms in only a few cases. A response was achieved with high doses of dexamethasone and chloramphenicol in only one of 20 cases. Polyarthritis and liver abscesses in a number of lambs provided evidence of a previous bacteraemic or septicaemic episode but no definite source of the central nervous system infection was identified. In common with other infectious bacterial conditions which are prevalent during the early life of sheep, control measures should ensure an adequate transfer of passive antibody, repeated treatments of the navel, and hygienic conditions in the lambing and rearing environments.

Three ewes with naturally occurring pregnancy toxaemia and increased plasma glucose concentrations within 24 h of the onset of clinical signs, made a complete recovery following treatment with a concentrated oral rehydration solution. Four ewes in which plasma glucose concentrations fell did not recover. Ewes with elevated plasma alkaline phosphatase concentrations were slower to recover than ewes with normal plasma alkaline phosphatase concentrations. These findings suggest that plasma alkaline phosphatase concentration and change in plasma glucose concentration might offer useful prognostic indices in cases of ovine pregnancy toxaemia, and influence a decision to perform an elective caesarean operation. Further studies using a larger number of ketotic ewes are necessary before firm conclusions can be made.

An enteric disease has occurred for four consecutive years (1989 to 1992) in a spring-calving beef suckler herd in east central Scotland affecting seven- to 12-week-old beef calves. The affected animals remained pyrexic (40 to 42 degrees C) with an acute enteritis which progressed in some cases to severe mucohaemorrhagic colitis. Despite intensive antibiotic and fluid therapy 25 per cent of the affected calves died after five to 10 days of illness. Post mortem examination revealed ulceration and necrosis of the mucosa of the abomasum and small and large intestine. Haematological examinations revealed a severe, non-regenerative neutropenia. Histopathological examination of gut and associated lymphoid tissue revealed lesions similar to those described in bovine viral diarrhoea/mucosal disease (BVD/MD) infection but detailed investigations failed to reveal evidence of active BVD virus infection in the herd. No aetiological agent has been found in association with this disease, for which the term necrotic enteritis is proposed.

Meningoencephalitis was recorded in 10 two- to 14-day-old calves during a two-year field study. Analysis of lumbosacral cerebrospinal fluid revealed a marked increase in protein concentration with a pronounced neutrophilic pleocytosis. Three calves with positive bacteriological cultures which were treated with chloramphenicol survived whereas six calves treated with penicillin G had to be destroyed on humane grounds after their condition deteriorated. Only two of the 10 calves had concurrent lesions of omphalophlebitis which may indicate that this is not the major route of bacterial invasion in neonatal meningoencephalitis. None of the constituents of cerebrospinal fluid proved to be a reliable prognostic indicator of meningoencephalitis. It is concluded that the analysis of cerebrospinal fluid is a useful ancillary aid in the investigation of abnormal mental states in neonatal calves and a sensitive test for the presence of an inflammatory lesion involving the leptomeninges.