Nociceptive threshold, blood constituents and physiological values in 213 cows with locomotion scores ranging from normal to severely lame.

The aim of this study was to investigate associations between mechanical nociceptive threshold, blood constituents, physiological measurements and locomotion score (LS) in dairy cattle with a range of LS from 1 (normal) to 5 (severely lame). The study used 213 Friesian/Friesian cross dairy cows from 12 farms. There were 40-50 cows each with LS 1-4 and 22 cows with LS 5. Each cow was restrained and her temperature and respiratory and cardiac rates were measured. Nociceptive threshold, plasma concentrations of haptoglobin, ß-hydroxybutyrate (ß-HB), cortisol, glucose, lactate, creatinine kinase activity, packed cell volume and white blood cell counts were determined. Mixed effect models were used to investigate associations between the variables measured and LS. Parity and stage of lactation were forced into all analyses and the model fit was checked by investigation of residuals. After accounting for parity and stage of lactation, nociceptive threshold was significantly lower in cattle with LS 3-5 compared with LS 1 in a dose response manner, indicating increasing hyperalgesia with increasing LS. Haptoglobin concentration was raised in all cattle with LS>1, demonstrating an inflammatory response with all levels of lameness. Cortisol and glucose concentrations were lower and ß-HB concentrations higher in cows with LS 2 compared with cows with other scores, possibly signifying metabolic challenge. Heart and respiratory rate and rectal temperature were significantly higher only in cows with LS 5, suggesting that these measurements were insensitive measures of pain or stress. It was concluded that hyperalgesia increases with increasing severity of lameness and that nociceptive pressure and haptoglobin were sensitive measures of pain from lameness.

Multilocus sequence typing of intercontinental bovine Staphylococcus aureus isolates.

A total of 258 bovine-associated Staphylococcus aureus isolates from the United States, Chile, and the United Kingdom, plus the reference isolate S. aureus Newbould 305 (NCIMB 702892), were analyzed by multilocus sequence typing (MLST). A collection of previously characterized United Kingdom isolates were also included in the analysis. The results demonstrated that MLST is suitable for the differentiation of bovine S. aureus isolates from various sites (milk, teat skin, milking machine unit liners, hands, and bedding) and countries. The theory of the host specificity of S. aureus is supported by the detection of a previously undescribed clonal complex that comprised 87.4% of the isolates studied, with representatives from all geographic locations investigated. This suggests that a single clonal group has achieved a widespread distribution and is responsible for the majority of infections. Some sequence types (STs; ST25, ST115, ST124, and ST126) demonstrated site specificity, as they were significantly (P < 0.05) associated with milk or teat skin.

Risk factors for bulk milk somatic cell counts and total bacterial counts in smallholder dairy farms in the 10th region of Chile.

We investigated the principal management factors that influenced bulk milk somatic cell count (BMSCC) and total bacterial count (TBC) of smallholder dairy farms in the 10th region of Chile. One hundred and fifty smallholder milk producers were selected randomly from 42 milk collection centres (MCCs). In April and May of 2002, all farms were visited and a detailed interview questionnaire on dairy-cow management related to milk quality was conducted. In addition, the BMSCC and TBC results from the previous 2 months' fortnightly tests were obtained from the MCCs. The mean BMSCC and TBC were used as the dependent variables in the analyses and were normalised by a natural-logarithm transformation (LN). All independent management variables were categorised into binary outcomes and present (=1) was compared with absent (=0). Biserial correlations were calculated between the LNBMSCC or LNTBC and the management factors of the smallholder farms. Management factors with correlations with P0.05) factors. A random MCC effect was included in the models to investigate the importance of clustering of herds within MCC. In the null model for mean LNTBC, the random effect of MCCs was highly significant. It was explained by: milk collected once a day or less compared with collection twice a day, not cleaning the bucket after milking mastitic cows versus cleaning the bucket and cooling milk in a vat of water versus not cooling milk or using ice or a bulk tank to cool milk. Other factors that increased the LNTBC were a waiting yard with a soil or gravel floor versus concrete, use of plastic buckets for milking instead of metal, not feeding California mastitis test (CMT)-positive milk to calves and cows of dual-purpose breed. The final model explained 35% of the variance. The model predicted that a herd that complied with all the management practices had a mean predicted TBC of 105 colony forming units (cfu)/ml, whereas a herd that did not comply with any of these management factors had a predicted TBC of 59 x 10(9)cfu/ml. The model of mean LNBMSCC explained 18% of the variance; the random effect of MCC was not significant. Management factors that decreased the mean LNBMSCC were: using the CMT for 1 year versus using the test for more than 1 year or not at all, absence of a concrete waiting yard, not filtering the milk or using filters other than a plastic sieve to filter the milk, milking cows with mastitis last, and sometimes or always examining the udder before milking. A herd that complied with all of these management factors had a BMSCC of approximately 46,166 cells/ml, whereas a herd that did not comply with any of the management practices above had a mean BMSCC of 2 x 10(6)cells/ml.

Risk factors associated with BMSCC greater than 200 000 cells/ml in dairy herds in southern Chile.

A cross-sectional survey of 523 dairy farms in the south of Chile was carried out to quantify risk factors associated with bulk-milk somatic-cell count (BMSCC) >200 x 10(3)cells/ml. Questionnaires followed by one reminder were sent to 3710 dairy farms via the 11 milk-processing plants that they supplied in October 1998. The response proportion was 14.1%. The median BMSCC was 289 x 10(3) cells/ml (range: 74 x 10(3) to 1800 x 10(3)cells/ml). The median herd size was 70 cows (range: 7-616); herd size was not associated with BMSCC. The annual milk yield of 33.2% of the herds was <4000 l and 53.4% had an annual milk yield of 4 x 10(3) to 6 x 10(3) l. Clinical-mastitis records were kept by 55.3% of the farmers. Seventy-six percent of the farmers (377/499) reported <10 clinical cases of mastitis in the year prior to the questionnaire. Logistic multiple regression indicated that BMSCC >200 x 10(3)cells/ml was more likely when foremilking was practised, and when cows were collected in a yard before milking. BMSCC was less likely to be >200 x 10(3)cells/ml when teats were washed with water containing disinfectant compared with plain water; when the udder and teats were always checked before milking compared with, sometimes or never; when cows with mastitis were milked first compared with any other ordering, and when farmers recorded individual-cow somatic-cell count (ICSCC) compared with when ICSCC was not recorded.