Journal Articles
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Item The prevalence of damaged tails in beef cows, pregnant dairy heifers and weaned dairy calves(Taylor and Francis Group on behalf of the New Zealand Veterinary Association, 2025-07-09) Cuttance EL; Mason WA; Bryan MA; Laven RAAims: To determine the prevalence of tail deviations, trauma and shortening in weaned dairy calves, pregnant dairy heifers and beef cows on a selection of New Zealand farms, and to compare results to those recorded in lactating dairy cows. Methods: This was a cross-sectional observational study. For beef cows, 25 farms were randomly selected from two veterinary practices. For dairy heifers and calves, data were collected from farms (70 and 76, respectively) previously involved in a study of tail damage in lactating cows. All cattle were tail scored using a modification of the New Zealand Veterinary Association Scoring System. Tails were palpated and lesions recorded as deviated (non-linear deformity), shortened, or traumatic (all other lesions). Cows could have more than one lesion, but for the prevalence calculations, only the presence/absence of a particular lesion was assessed. Descriptive herd-level prevalence data were reported for all farms/cattle types. For dairy heifers, the prevalence of tail deviation was compared to that in adult cows on the same farm. Results: For beef cattle, median prevalence of any tail damage was 4.0% (min 0.0, max 37.5%), and for deviations + trauma, it was 2.0% (min 0.0, max 16.7%). For dairy heifers, equivalent figures were 1.7% (min 0.0, max 17.8%) and 1.3% (min 0.0, max 17.8%). In weaned calves, the median prevalence of any damage was 0% (min 0.0, max 11.6%): almost all damage (61/64 cases) was deviation. Farms with a heifer prevalence of deviations > 2% had a mean cow prevalence of deviations 3.65 (95% CI = 0.7–6.6)% higher than herds with heifer prevalence ≤ 2%, but this explained only 9% of the variation in log percentage cow prevalence. Conclusions and clinical relevance: In all groups, median prevalence of tail damage was low (and lower than reported in dairy cows), but individual farms had high levels of damage. Beef cows were more likely to have shortened or traumatised tails than dairy heifers/calves, perhaps from an increased prevalence of faecal tail rings. Limited association between the prevalence of tail deviations in heifers and lactating cows on the same farm, and generally lower levels of tail damage in heifers, do not support the hypothesis that tail damage in cows principally results from damage earlier in life. This study adds support to our hypothesis that poor handling/infrastructure are responsible for most tail damage in dairy cows.Item The prevalence of damaged tails in New Zealand dairy cattle.(Taylor and Francis Group, 2024-03-11) Cuttance EL; Mason WA; Hea SY; Bryan MA; Laven RAAIMS: To undertake a survey of the prevalence of tail deviations, trauma and shortening on a representative selection of New Zealand dairy farms, and to assess whether sampling based on milking order could be used instead of random sampling across the herd to estimate prevalence. METHODS: This was a cross-sectional observational study, with 200 randomly selected farms enrolled across nine regions of New Zealand via selected veterinary practices (one/region). Veterinary clinics enrolled 20-25 farms each depending on region, with 1-2 trained technicians scoring per region. All cows (n = 92,348) present at a milking or pregnancy testing event were tail scored using a modified version of the New Zealand Veterinary Association Industry Scoring System. Palpated lesions were recorded as deviated (i.e. non-linear deformity), shortened (tail shorter than normal) or traumatic (all other lesions). The location of lesions was defined by dividing the tail into three equal zones: upper, middle and lower. A cow could have more than one lesion type and location, and/or multiple lesions of the same type, but for the prevalence calculation, only the presence or absence of a particular lesion was assessed. Prevalence of tail damage calculated using whole herd scoring was compared to random sampling across the herd and sampling from the front and back of the milking order. Bootstrap sampling with replacement was used to generate the sampling distributions across seven sample sizes ranging from 40-435 cows. RESULTS: When scoring all cows, the median prevalence for deviation was 9.5 (min 0.9, max 40.3)%; trauma 0.9 (min 0, max 10.7)%, and shortening was 4.5 (min 1.3, max 10.8)%. Deviation and trauma prevalence varied between regions; the median prevalence of deviations ranged from 6% in the West Coast to 13% in Waikato, and the median prevalence of all tail damage from 7% in the West Coast to 29% in Southland. Sampling based on milking order was less precise than random sampling across the herd. With the latter and using 157 cows, 95% of prevalence estimates were within 5% of the whole herd estimate, but sampling based on milking order needed > 300 cows to achieve the same precision. CONCLUSIONS AND CLINICAL RELEVANCE: The proportion of cows identified as having damaged tails was consistent with recent reports from New Zealand and Ireland, but at 11.5%, the proportion of cows with trauma or deviation is below acceptable standards. An industry-wide programme is needed to reduce the proportion of affected cows.Item Suckling behavior of calves in seasonally calving pasture-based dairy systems, and possible environmental and management factors affecting suckling behaviors.(Elsevier Inc and the Federation of Animal Science Societies (FASS) Inc on behalf of the American Dairy Science Association, 2022-07) Cuttance EL; Mason WA; McDermott J; Laven RAIn recent years, interest has been increasing in whether farmed animals are able to live a reasonably natural life, with one particular area of concern being calf-dam separation. The objectives of this study were to monitor the timing and frequency of suckling behavior of calves left on pasture to suckle their dams for up to 24 h (interquartile range 4.0-15.5 h) and to investigate possible risk factors that may contribute to any variability seen. Over 2 yr, a convenience sample of 8 farms (4 in the North Island, 4 in the South Island of New Zealand) were involved in an observational study where cows and calves were observed for 24 h a day over a 2-wk-long period per farm. During the observation period, farmers continued to remove calves at the same frequency they normally did (which ranged from once a day to 4 times a day). Cows (between 2 and 12 yr old) and calves were observed from a scissor lift in or beside the calving paddock. Cows had numbers written on them, and observers used binoculars and spotlights. Observers recorded the length of stage 2 labor, time of birth, standing, and first suckling, number of suckling events, time of calf removal from the dam, temperature where the cows were grazing, and size of the grazing area they were calving in. Dams were body condition scored before calving, and their age was extracted from farm records. A total of 697 calves were observed during the study. A total of 444 of 697 calves [63.7%; 95% confidence interval (CI) = 60.0-67.3%] suckled in the calving paddock (farm range 40.0% to 90.2%). Of the 444 calves that suckled in the calving paddock, 407 (58.4%; 95% CI 54.6-62.1%) suckled within the first 6 h after birth (farm range 33.0% to 83.6%). Individual risk factors associated with the hazard rate ratio (HR) for time to first suckling event were time to standing (calves who took more than 1.3 h to stand had a longer time from birth to first suckle) and age of the dam [compared with calves that were born from dams >7 years of age, calves born to dams that were 2-3 and 4-7 yr of age had a 1.49 (95% CI 1.07-2.06) and 1.19 (95% CI 0.89-1.60) HR, respectively, for time from birth to first suckle in the calving paddock]. Farm risk factors associated with the HR of suckling were frequency of calf collection [calves that were born on farms that collected calves once a day suckled earlier than calves on farms that removed calves more than once a day (HR 1.52; 95% CI 1.25-1.84)] and temperature [a minimum temperature of <10°C within 6 h of a calf being born was associated with a 0.69 (95% CI 0.53-0.89) hazard of suckling in the calving paddock]. We observed very large farm variability that urgently requires further investigation if pasture-based farms are ever to adopt a system where calves remain with their dams for longer than 24 h.