Browsing by Author "Mason W"

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    Comparison of a novel culture-based selection for dry cow therapy with somatic cell count-based selection: Comparing detection rates for major pathogens and subsequent udder health outcomes
    (Cambridge University Press on behalf of Hannah Dairy Research Foundation., 2025-09-18) Cuttance E; Nortje R; Laven R; Mason W
    This study compared a culture-based protocol in which only cows identified as having intramammary infections due to major pathogens (major IMI) were treated with dry cow antibiotics (DCAT) compared with the current New Zealand somatic cell count (SCC) and mastitis-based algorithm. Healthy multiparous pregnant lactating cattle (n = 1541) were enrolled from three spring-calving New Zealand farms. A composite four-quarter milk sample was collected aseptically prior to the last milking before dry-off. Samples underwent standard culture and a culture using a novel, custom-made agar plate. Enrolled animals were classified as having a major IMI on 1) standard culture; 2) novel culture and 3) having SCC > 150,000 cells/ml at the last herd test and/or clinical mastitis (CM) in the current lactation. The sensitivity and specificity of novel culture and SCC/mastitis history for identifying cows with major IMI (compared with standard culture) were calculated. Cows were then blocked by standard culture results (major, minor or no growth) and randomly allocated to treatment based on either novel culture results (cult-SDCT) or SCC/mastitis history (alg-SDCT). Cows allocated to cult-SDCT whose novel culture result was major pathogen positive or contaminated received DCAT, while for alg-SDCT cows, all cows with either SCC > 150,000 cells/ml at the last herd test or CM in the current lactation received DCAT. The sensitivity (0.80 vs 0.67) and specificity (0.91 vs 0.81) for major IMI prediction were greater for cult-SDCT than alg-SDCT. After accounting for farm, age and dry-off SCC, alg-SDCT cows had marginal mean SCC at first herd test post-calving of 129,000 (95% CI 116-143,000) cells/ml, whereas the equivalent for cult-SDCT cows was 113,000 (95% CI 101-126,000) cells/ml. Compared to alg-SDCT, using cult-SDCT correctly identified a higher proportion of major IMI identified by standard culture and did not result in an increase in post-calving SCC.
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    Lameness recovery rates following treatment of dairy cattle with claw horn lameness in the Waikato region of New Zealand.
    (Taylor and Francis Group, 2023-09-01) Mason W; Laven LJ; Cooper M; Laven RA
    AIMS: To describe the time in days for lame dairy cows to recover after diagnosis and treatment of claw horn lameness, and to investigate whether cure rates differed between farms. METHODS: Five dairy farms in the Waikato region were conveniently enrolled into a descriptive epidemiological study. Three of these farms had dairy cattle enrolled over two consecutive seasons, while two farms enrolled for one year. Lame cattle diagnosed by the farmers were enrolled into the study if they had a lameness score (LS ≥ 2 on a 0-3 scale) and claw horn lesions. All enrolled animals were treated by a single veterinarian following a consistent methodology, and subsequently assessed for LS at a median frequency of 4 days from enrolment until they were sound (LS = 0). The times (days) taken for animals to become sound and non-lame (LS < 2) were reported for all animals, and Kaplan-Meier survival curves used to present the results. A Cox-proportional hazard model was used to assess if the hazard of soundness was associated with farm, age, breed, lesion, number of limbs involved, and LS at enrolment. RESULTS: A total of 241 lame cattle with claw horn lesions were enrolled across the five farms. White line disease was the predominant pain-causing lesion in 225 (93%) animals, and blocks were applied to 205 (85%) of enrolled animals. The overall median days from enrolment to becoming sound was 18 (95% CI = 14-21) days, and 7 (95% CI = 7-8) days to become non-lame. A difference in the hazards of lameness cure between farms was identified (p = 0.007), with median days to lameness cure between farms ranging from 11 to 21 days. No associations were identified between age, breed, limb, or LS at enrolment on the lameness cure rates. CONCLUSIONS: Treatment of claw horn lameness following industry-standard guidelines in dairy cattle on five New Zealand dairy farms resulted in rapid cure, although cure rates differed between farms. CLINICAL RELEVANCE: Following industry best-practice lameness treatment guidelines, including frequent use of blocks, can result in rapid lameness cure rates in New Zealand dairy cows. This study also suggests that management of lame cattle on pasture can positively benefit their welfare and recovery times. The reported cure rates provide veterinarians with benchmarks on the length of time after which a lame animal should be re-examined, and in the investigation of poor treatment response rates at the herd level.