The aim of this study was to characterize peripartum metabolic profiles, including the insulin sensitivity index, in cows diagnosed with subclinical ketosis (SCK) in the early stage of lactation. Cows that calved from January 2011 through December 2014 on a dairy farm with alarm level prevalence of SCK in Hokkaido, Japan (n = 175) were used. Blood and body condition scores (BCS) were obtained at regular health examinations in 2 consecutive periods, the first between 14 and 2 d before parturition, and the second between 3 and 14 d after parturition. Animals were divided into 3 groups at postpartum sampling: an SCK group with 35 multiparous and 15 primiparous cows having β-hydroxybutyrate (BHBA) concentrations ≥ 1.2 mM without clinical signs, a disease group of 36 multiparous and 9 primiparous cows that received treatment between parturition and postpartum sampling, and a control group consisting of 49 multiparous and 31 primiparous cows with BHBA concentrations < 1.2 mM. The prepartum revised quantitative insulin sensitivity check index was significantly lower in the multiparous SCK and disease groups than in the control group, demonstrating decreased insulin sensitivity in these cows, but not in primiparous cows. The prepartum BCS was significantly higher only in the multiparous SCK and disease groups. The prepartum apolipoprotein B-100 (ApoB-100) concentration was significantly decreased in the multiparous disease group, suggesting hepatic lipidosis. Conversely, primiparous cows had a higher prepartum ApoB-100 concentration. Prepartum decreased insulin sensitivity in the multiparous SCK and disease groups was considered to facilitate progression to SCK after calving.

Mycobacterium avium ssp. paratuberculosis (MAP) is the etiologic agent of Johne’s disease, a chronic contagious enteritis of ruminants that causes major economic losses. Several studies, most involving large free-stall herds, have found environmental sampling to be a suitable method for detecting MAP-infected herds. In eastern Canada, where small tie-stall herds are predominant, certain conditions and management practices may influence the survival and transmission of MAP and recovery (isolation). Our objective was to estimate the performance of a standardized environmental and targeted pooled sampling technique for the detection of MAP-infected tie-stall dairy herds. Twenty-four farms (19 MAP-infected and 5 non-infected) were enrolled, but only 20 were visited twice in the same year, to collect 7 environmental samples and 2 pooled samples (sick cows and cows with poor body condition). Concurrent individual sampling of all adult cows in the herds was also carried out. Isolation of MAP was achieved using the MGIT Para TB culture media and the BACTEC 960 detection system. Overall, MAP was isolated in 7% of the environmental cultures. The sensitivity of the environmental culture was 44% [95% confidence interval (CI): 20% to 70%] when combining results from 2 different herd visits and 32% (95% CI: 13% to 57%) when results from only 1 random herd visit were used. The best sampling strategy was to combine samples from the manure pit, gutter, sick cows, and cows with poor body condition. The standardized environmental sampling technique and the targeted pooled samples presented in this study is an alternative sampling strategy to costly individual cultures for detecting MAP-infected tie-stall dairies. Repeated samplings may improve the detection of MAP-infected herds.

Few studies have investigated the efficacy of extended ceftiofur therapy and none have focused on extended therapy for naturally occurring clinical mastitis. The objective of this study was to compare the efficacy of extended intramammary ceftiofur therapy of 8 d duration with a standard 2-day regimen for the treatment of naturally occurring mild to moderate clinical mastitis in lactating dairy cows. Holstein cows from 22 dairy herds (n = 241) were randomly allocated to the 2 treatment groups. For each case of mastitis, 125 mg of ceftiofur hydrochloride was administered intramammary once a day for 2 or 8 d. Clinical cure, 21 d after the last treatment, was 89% (98/110) in each group. Bacteriological cure 21 d after the last treatment for the 2- and 8-day regimens were 32% (15/47) and 61% (25/41), respectively, for all bacteria (P = 0.007), 64% (9/14) and 82% (9/11), respectively, for streptococci (P = 0.50), and 0% (0/20) and 47% (9/19), respectively, for Staphylococcus aureus (P = 0.0004). There were no statistical differences between groups for new intramammary infections. Overall, ceftiofur extended therapy increased cure when compared to a 2-day regimen for the treatment of naturally occurring mild to moderate clinical mastitis in lactating dairy cows.

Objective—To estimate the risk of subclinical Mycobacterium avium subsp paratuberculosis (MAP) infection in cows that ingested MAP DNA–positive raw colostrum as calves, compared with risk in cows that ingested MAP DNA–negative raw colostrum as calves. Animals—205 calves born in 12 commercial dairy herds. Procedures—Each calf was separated from its dam within 30 to 60 minutes after birth and fed raw colostrum. For each calf, samples of the colostrum fed were collected and tested for the presence of MAP DNA by use of a nested PCR assay for the target gene ISMAP02. Calves fed colostrum positive or negative for MAP DNA were classified into exposed (n = 69) and unexposed (136) groups, respectively. Each calf was tested for MAP infection at 30, 42, and 54 months of age by use of a serum ELISA and bacterial culture of feces. Weibull hazard regression models were used to evaluate the association between exposure to MAP DNA–positive colostrum and time to testing positive for MAP infection. Results—Hazard of MAP infection was not different between groups (exposed vs unexposed) when serum ELISA, bacterial culture of feces, or both diagnostic tests (parallel interpretation) were positive. Conclusions and Clinical Relevance—Heifer calves fed MAP DNA–positive colostrum were at no greater risk of MAP infection, compared with heifer calves fed MAP DNA–negative colostrum. This result contradicts findings from other studies and should be interpreted with caution.

Objective-To investigate the epidemiologic and financial impacts of targeted sampling of subpopulations of cows, compared with random sampling of all cows, for classification of dairy herd infection status for paratuberculosis. Animals-All cows from 4 infected herds with a low-to-moderate prevalence of paratuberculosis and from 1 noninfected herd in California. Procedure-The infection status of each cow was classified on the basis of results of an ELISA or combined ELISA and fecal culture results. Thirteen sampling schemes designed to randomly sample cows on the basis of lactation number, stage of lactation, and milk production were evaluated. Sampling without replacement was used to obtain a probability of herd detection of paratuberculosis for each evaluated sampling method and for simulated sample sizes between 30 and 150 cows. Marginal cost-effectiveness analysis was used to determine the cost increase relative to the increase in detection probability. Results-Sampling cows in the third or higher lactation and greater than or equal to 200 days into lactation yielded the highest detection probability in most instances, resulting in a detection probability that was 1.4 to 2.5 times that obtained by sampling 30 cows in the second or higher lactation. Costs of testing via the alternative method with a 95% detection probability were approximately $300 lower in a high-prevalence herd (31 %) and $800 lower in a low-prevalence herd (9%), compared with use of the reference method. Conclusions and Clinical Relevance-Detection of herds with paratuberculosis could be improved, and costs of testing substantially reduced by sampling targeted groups of cows.

The purpose of this study was to determine the relationship between the serum level of C-reactive protein (CRP) and lactation and health status. Blood samples were collected every 2 wk for 12 mo from 29 randomly selected dairy cattle on 3 farms. At the time the blood samples were collected, the stage of pregnancy, lactation status, breeding records, general health condition, reproductive status, and body condition score were recorded for each cow. Serum CRP was detected with sodium dodecyl sulfate polyacrylamide gel electrophoresis and western immunoblotting. C-reactive protein levels were measured with a densitometer and expressed as an optimal dose value. C-reactive protein levels were correlated with the body condition score, lactation status, and animal health (P < 0.05), but not with ambient temperature, animal age, or parity. C-reactive protein levels increased with milk production, peaking during high lactation (2 to 4 mo of pregnancy), and decreased when lactation ceased. In addition, the CRP level was highest during naturally occurring infections, such as mastitis and other tissue inflammation. Thus, the CRP level can confirm the presence of inflammation. The stress effect of taking blood samples as measured by the CRP level, was also examined. The CRP level became rapidly elevated 12 h after the blood samples were taken but returned to normal 36 h later. In conclusion, the stresses resulting from overall poor health, heavy lactation, and blood sampling caused the elevation of serum CRP. C-reactive protein is a marker or tool for evaluating the health status of a herd. C-reactive protein should also be considered as a useful criteria to assess the stress levels and may be useful in early surveillance of disease conditions in a dairy herd.

A field study involving 325 calves from 17 dairy herds in Saskatchewan was conducted to determine the risk of enzootic pneumonia and to assess its association with a number of factors. Two different case definitions of pneumonia were used in the analyses: the first was based on producers' treatment risk (CASE1) and the second was based on semimonthly clinical examinations of calves by the research veterinarian (CASE2). The risk of pneumonia based on CASE1 was 39% and on CASE2 was 29%. The measure of agreement between CASE1 and CASE2 at the calf level of analysis was poor (kappa = 0.24, SE = 0.02) and at the herd level of analysis was moderate (kappa = 0.40, SE = 0.12). The mortality risk from pneumonia was 1.8% and a variety of infectious organisms were isolated from pneumonic lungs. Twenty-seven percent of the calves had inadequate (total IgG < or = 800 mg/dL) levels of passively acquired antibodies as measured by radial immunodiffusion. The proportion of seropositive titers in calves within the first two weeks of age was 94% to parainfluenza 3 virus (PI3V) and bovine respiratory syncytial virus (BRSV), 73% to Pasteurella haemolytica (Ph), 68% to bovine viral diarrhea virus (BVDV), 67% to infectious bovine rhinotracheitis virus (IBRV), 46% to Mycoplasma dispar (Md), 44% to Haemophilus somnus (Hs), and 21% to Mycoplasma bovis (Mb). At the calf level of analysis and after adjusting for clustering, there was a negative association (p = 0.10) between the diagnosis of pneumonia based on CASE2 and total IgG levels and Ph titers (rPh).

A cross-sectional study was designed to determine the level ofawareness of selected dairy farmers to herd health program (HHP) and compliance in the Program LadangAngkat (PLA). The study also determined the association between farmers’ awareness and compliance in promoting herd health. An open-ended questionnaire was randomlyadministered to five dairy cattle farms within Selangor and Negeri Sembilan as representative dairy farms enlisted into the PLA of Faculty of Veterinary Medicine, Universiti Putra Malaysia. The mean herd size of the farms was 102.20±20.80, with a range of 30-160 heads of dairy cattle, having an average mean number of milking cows at 29.40±11.22. There was a higher (p<0.05) mean herd health awareness level (72.86±5.78%) among the farmers once compared with the mean compliance level (61.2 ± 4.1%) for 10 out of the 14 HHP components; with the lowest compliances being disease monitoring programme(33.20%) and biosecurity (39.9%). There was a significant (p<0.05), direct, weak positive correlation (r = 0.245; p = 0.042) between farmers’ awareness and farmers’ compliance to the 14 components of the HHP. This study highlights an appreciable level of awareness among dairy farmers in the PLA, with a relatively low compliancelevels to the HHP components.

The objective of this study was to describe the association between thermal measures in the barn environment (pen temperature and humidity) and fecal shedding of Salmonella in dairy cattle. A repeated cross-sectional study was conducted within a commercial dairy herd located in the midwestern United States. Five pooled fecal samples were collected monthly from each pen for 9 mo and submitted for microbiological culture. Negative binomial regression methods were used to test the association [incidence rate ratio (IRR)] between Salmonella pen status (the count of Salmonella-positive pools) and thermal environmental parameters [average temperature and temperature humidity index (THI)] for 3 time periods (48 h, 72 h, and 1 wk) before fecal sampling. Salmonella was cultured from 10.8% [39/360; 95% confidence interval (CI): 7.8% to 14.5%] of pooled samples. The highest proportion of positive pools occurred in August. The IRR ranged from 1.26 (95% CI: 1.15 to 1.39, THI 1 wk) to 4.5 (95% CI: 2.13 to 9.51, heat exposure 1 wk) across all thermal parameters and lag time periods measured. For example, the incidence rate of Salmonella-positive pools increased by 54% for every 5°C increment in average temperature (IRR = 1.54; 95% CI: 1.29 to 1.85) and 29% for every 5-unit increase in THI (IRR = 1.29; 95% CI: 1.16 to 1.42) during the 72 h before sampling. The incidence rate ratio for pens exposed to higher temperatures (> 25°C) was 4.5 times (95% CI: 2.13 to 9.51) the incidence rate ratio for pens exposed to temperatures < 25°C in the 72 h before sampling. Likewise, the incidence rate ratio for pens exposed to THI > 70 was 4.23 times greater (95% CI: 2.1 to 8.28) than when the THI was < 70 in the 72 h before sampling. An association was found between the thermal environment and Salmonella shedding in dairy cattle. Further research is warranted in order to fully understand the component risks associated with the summer season and increased Salmonella shedding.