Sample prevalence and molecular characterisation of Cryptosporidium andersoni within a dairy herd in the United Kingdom

Bovine cryptosporidiosis is usually an acute diarrhoeal disease of young calves caused by Cryptosporidium parvum. However, chronic infection with Cryptosporidium andersoni has been associated with gastritis, reduced milk yield and poor weight gain in adult cattle. Here we describe the first genetic confirmation and characterisation of C. andersoni from cattle in the United Kingdom and its sample prevalence within a dairy herd. Oocysts measured 7.5+/-0.4 microm x 5.5+/-0.4 microm (7.0-8.5 microm x 4.5-6.5 microm) with a length-to-width ratio of 1.37 (1.08-1.60). The within-herd sample prevalence was 16% (95% confidence intervals=10.4-21.6%). Nested polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and sequence analysis of the small subunit rDNA was used to confirm the species and characterise the isolates. Due to the lack of overt, acute, clinical symptoms, the incidence, prevalence and importance of this parasite is probably currently underestimated in cattle in the UK. The potential for zoonotic transmission is unknown.     

Survey of the operation of dairy herd health schemes by veterinary practices in the United Kingdom.

A postal survey of 566 veterinary practices with dairy farms among their clients showed that the majority of the practices were very positive about the benefits of running a herd health scheme. Nevertheless, only a third of them were running a scheme, and most had attracted only a small number of clients. The size of the practice (in terms of the number of veterinarians and the number of dairy farming clients) was the most significant factor determining whether a practice was likely to run a herd health scheme, and the age of the veterinarians did not appear to have any affect.     

Mycoplasma bovis and otitis in dairy calves in the United Kingdom

Signs of severe otitis media in 20% of dairy calves on one farm were associated with Mycoplasma bovis infection, based on isolation from the external ear canal and nares. Affected calves seroconverted to M. bovis and no other significant bacteria were isolated. Infection was considered likely to have originated from cows in the milking herd based on evidence of seroconversion and detection of infection in a milk sample. M. bovis infection should be considered when investigating otitis problems in calves.     

Economic losses caused by paratuberculosis in a dairy herd: case report

The impact of clinical paratuberculosis in a 500 cow Jersey x Holstein dairy herd of loose housing system was followed up for three years. There was an increasing fall in annual milk production, namely 49, 474, and 1030 litres per cow, a decrease in the average age from 63.9 to 57.0 months, and of feed conversion from 60 to 39%. The effect of certain management deficiencies, existing throughout the study, is discussed.     

Economic consequences of postponed first insemination of cows in a dairy cattle herd

The purpose was to analyse the economic consequences of postponed first insemination of cows in dairy herds with different reproduction management, and to analyse the sensitivity of the results to a further decrease in beef prices, using a model simulating production and health in a dairy cattle herd. Three different period-to-first-insemination scenarios were analysed. Period to first insemination was defined as days post partum for initiating insemination at observed heat. The three scenarios consisted of a short period to first insemination (70 days for primiparous and 35 days for older cows), a 70 days postponed first insemination of primiparous cows and a scenario with 70 days postponed first insemination for all cows. At a 70 days postponed first insemination for primiparous cows a decrease in annual herd profit of 1% were found. A 70 days postponed first insemination for all cows led to a decrease in annual herd profit by 3% at good reproductive efficiency and 4% at poor reproductive efficiency. The herd profit was calculated as the profit to cover labour costs and fixed costs. Postponed inseminations might reduce labour per cow-year. The reduction in labour per cow-year need to be 3.2 h at good reproductive efficiency and 4.3 h at poor reproductive efficiency to counterbalance the reduction in herd profit by postponing first insemination for all cows by 70 days. In a situation with a 50% decrease in beef prices in a herd constrained by a milk quota (optimising profit per kg milk) herd profit was increased by 0.8% at good reproductive efficiency and 0.3% at poor reproductive efficiency by postponing first insemination for all cows by 70 days.     

Mycoplasmal mastitis in a dairy herd

In October 1985, mycoplasmas were isolated from bulk tank milk samples in a large Florida dairy (greater than 1,400 lactating cows). At that time, measures to isolate and control the spread of infection were instituted. In an initial screening test, Mycoplasma bovis was isolated from 21 of 153 milking string samples (milk from all quarters of 10 cows/string). Composite quarter milk samples from all quarters of every individual lactating cow in the herd were obtained for culture in November 1985 and December 1985. In October, 88 of 1,535 (5.7%) cows were identified as Mycoplasma-positive. An additional 31 Mycoplasma-infected cows were identified in December. The dairy elected to maintain the infected cows in a separate Mycoplasma-positive subherd, which would be milked at the end of each milking session. Seven additional Mycoplasma-positive cows were identified at initiation of lactation. All newly identified infected cows were transferred to the Mycoplasma-positive subherd. After segregation of Mycoplasma-positive cows, bulk tank milk samples obtained routinely from the main herd remained culture negative throughout the study. From February 1986 to October 1986, quarter milk samples were obtained monthly from cows in the Mycoplasma-positive subherd. Any cow that developed clinical mastitis or substantial decrease in milk production was, at the discretion of the herdsman, culled. Of the 126 cows in the subherd, 22 (17.5%) were culled for mastitis, 35 (27.8%) were culled for low production, and 9 (7.1%) were culled for other reasons. Of the remaining 60 cows, 16 (12.7% of the 126 cows) were Mycoplasma-positive on the basis of results from one or more samples obtained after February 1986.(ABSTRACT TRUNCATED AT 250 WORDS)     

Terbufos poisoning in a dairy herd

This report describes the accidental poisoning of over 200 head of Holstein cattle by the organophosphate, terbufos. The ingestion of an acutely toxic dose (approximately 7.5 mg/kg) of terbufos by 84 heifers resulted in severe respiratory distress as the primary clinical sign and death within 12 hours. There was no response to treatment with atropine sulfate. One hundred and twenty milking cows received a portion of the contaminated feed diluted approximately ten times. These cattle had typical signs of organophosphate poisoning and responded to atropine sulfate. Severely affected cows received pralidoxime chloride and activated carbon 48 h after terbufos ingestion but did not respond to the drugs. Diagnosis of organophosphate poisoning was confirmed by tissue and feed analysis for terbufos and measurement of whole blood cholinesterase activity.     

Phosphorus deficiency in a dairy herd

Phosphorus deficiency was diagnosed in a 90 cow seasonal supply dairy herd which showed low milk production, ill-thrift, infertility and osteophagia. Serum inorganic phosphorus and pasture phosphorus levels were low, pasture Ca:P ratios high and soil phosphorus levels very low; the soil phosphate retention value was 96%. The deficiency, which had probably existed for several years, was considered to be due to inadequate annual phosphate fertiliser applications on a high phosphate retaining soil. Phosphorus deficiency may have been exacerbated by the application of lime without phosphate several months before the onset of severe clinical disease. The finding of low sodium levels in pasture samples suggested that sodium deficiency may have co-existed and contributed to the clinical picture. Treatment, comprising bone flour dusting of pasture, water trough supplementation and phosphorus-containing injections, appeared to induce ovarian activity in anoestrous cows and suppress osteophagia, though controlled treatment trials were not performed. No improvement was noted in milk production or cow condition. Increased annual super-phosphate and reduced potassium applications were recommended, together with the monitoring of pasture and soil macro elements and serum phosphorus levels. A decision on whether to supplement with sodium would be based on the results of pasture monitoring, since a direct animal test is not currently available. It is suggested that phosphorus deficiency may not be uncommon in dairy herds in some North Island districts; based on the present case, the decline in New Zealand superphosphate quality in the 1970's and recently published data which has shown a high proportion of pasture phosphorus deficient sites in some North Island areas.     

Monensin toxicosis in a dairy herd

An acute onset of illness was reported in a lactating dairy herd in Canada in which monensin had been incorporated in error in its ration at almost 10 times the prescribed level. All of the lactating cows became lethargic, were inappetant, developed diarrhea, and had decreased milk production from 28 kg/cow/day, the day before exposure, to 23 kg/cow/day, 3 d later. Within 9 d, all animals recovered from the incident and milk production returned to previous levels.