Sampling strategies for assessing lameness, injuries, and body condition score on dairy farms

Abstract

Our objective was to evaluate how sampling strategies (i.e., how many cows to sample and which animals to include) used in 4 dairy cattle welfare assessment programs affect the classification of dairy farms relative to thresholds of acceptability for animal-based measures. We predicted that classification performance would improve when more cows were sampled and when selecting from all lactating cows versus when some pens were excluded. On 38 freestall farms, we assessed all 12,375 cows for lameness, injuries on the tarsal (hock) and carpal joints, and body condition score and calculated the farm-level prevalence for each measure. Based on approaches used in the industry, we evaluated 6 sampling strategies generated using formulas with precision (d) of 15, 10, or 5% applied to either a single high-producing pen or all lactating cows; an additional sample was included with d = 10% applied to the entire herd, selecting lactating cows in proportion to their representation in the herd. For each sampling strategy, cow records were selected randomly (in 10,000 replicates) to calculate prevalence. The strategy of assessing all cows in the high-producing pen was also compared. Farms were classified as meeting (below) or failing to meet (above) thresholds of ≤15% moderate lameness; ≤20% moderate carpal or hock injuries; <10, <5, and ≤1% severe lameness; or injuries on the carpus or hock; and <5, <3, <1, or 0% thin cows. For each measure and threshold, we calculated pooled percent agreement, kappa, sensitivity, specificity, and positive and negative predictive value for each sampling strategy using true prevalence as the gold standard for herd classification.Across measures and thresholds, classification performance increased with the number of cows sampled [i.e., when narrower precision values (d = 5 vs. 10 vs. 15%) were used in the sample size calculation]. Because narrower precision values can dramatically increase sample size, assessment programs may need to consider both feasibility and the degree of misclassification they will accept. Applying the formula directly to lactating cows performed better than applying it to the entire herd and then selecting lactating cows in proportion to their representation in the herd. Farm classifications were similar whether cows in the hospital pen were included or excluded from the sample. Selecting all cows from the high-producing pen resulted in classifications similar to when including all lactating cows, suggesting that assessing cows from the high-producing pen may serve as an acceptable proxy for all lactating cows on the farm.

Comparative Growth and Economic Performances between Indigenous Swamp and Murrah Crossbred Buffaloes in Malaysia

“…There were two types of buffalo breeds available in this farm, the Swamp and the Murrah × Swamp crossbred, representing 54% and 46% of the total buffalo population, respectively. The sample size in this study was represented by 10% to 15% of the total buffaloes in the farm, according to the Cochran method [13,14]. The sample size reflected proportions of the population in the farm, with the buffaloes selected randomly.…”

“…The reduced cost due to change of management also has increased when shorter calving interval period and first calving age are taken after new intervention. 1-13 : 1 Estimation value of improved birth weight per year (MYR); 2 Estimation value of increase number calf per year (MYR); 3 Estimation value of selling calves to other farms for fattening per year (MYR); 4 Estimation number of calves sales; 5 Estimation of shorter calving interval after new feeding management cost (MYR); 6 Estimation of shorter first calving age after new feeding management cost (RM); 7 Estimation of organic fertilizer per year (RM); 8 Estimation of flushing cost per year (MYR); 9 Estimation of additional calf feed cost per year (MYR); 10 Estimation of additional feed cost of total population of calf-heifer per year (MYR); 11 Estimation of additional in deworming cost per year (MYR); 12 Estimation of additional cost for ID tag per year (MYR); 13 Estimation of net gain or loss per year (MYR).…”

Changes in Saliva Analytes Associated with Lameness in Cows: A Pilot Study

“…In our study, changes in salivary analytes in cows with lameness were evaluated. The lameness severity showed a scoring mean of 3, considered as moderate [20]. This degree of severity represents more the usual situation on the farms of our area where more severe lameness are not so frequent.…”

Каліцтво Тварин Як Предмет Судово-Ветеринарної Експертизи

“…Аналіз останніх досліджень і публікацій. Наслідком жорстокого поводження чи інших неправомірних дій з тваринами є заподіяння їм різних за характером тілесних ушкоджень за різних обставин, зокрема, під час порушення правил утримання і експлуатації [8], перевезення [9], завантаження у транспортні засоби й вивантаження з них [10], дресирування [11], використання у різних видовищних заходах [12], надання ветеринарної допомоги [13], постановкою на тваринах не наукових експериментів [14], дорожньо-транспортними пригодами за участі тварин [15], сексуальним насиллям над ними [16], примушування тварин до виконання неприродних для них дій, що призводять до травмувань [17], незаконного добування мисливських тварин [18], примушування до нападу одних тварин на інших [19], відловом тварин [20], порушення правил обслуговування тварин [21] тощо.…”