Efficacy of statistical process control procedures to identify deviations in continuously measured physiological and behavioral variables in beef heifers resulting from an experimentally combined viral–bacterial challenge

The objective of this experiment was to determine if statistical process control (SPC) procedures coupled with remote continuous data collection could accurately differentiate between animals experimentally inoculated with a viral–bacterial (VB) challenge or phosphate buffer solution (PBS). Crossbred heifers (N = 38; BW = 230 ± 16.4 kg) were randomly assigned to treatments by initial weight, average daily gain (ADG), bovine herpes virus 1, and Mannheimia haemolytica serum titers. Feeding behavior, dry matter intake (DMI), animal activity, and rumen temperature were continuously monitored remotely prior to and following VB challenge. VB-challenged heifers exhibited decreased (P < 0.01) ADG and DMI, as well as increased (P < 0.01) neutrophils and rumen temperature consistent with a bovine respiratory disease (BRD) infection. However, none of the heifers displayed overt clinical signs of disease. Shewhart and cumulative summation (CUSUM) charts were evaluated, with sensitivity and specificity computed on the VB-challenged heifers (n = 19) and PBS-challenged heifers (n = 19), respectively, and the accuracy was determined as the average of sensitivity and specificity. To address the diurnal nature of rumen temperature responses, summary statistics (mean, minimum, and maximum) were computed for daily quartiles (6-h intervals), and these quartile temperature models were evaluated separately. In the Shewhart analysis, DMI was the most accurate (95%) at deciphering between PBS- and VB-challenged heifers, followed by rumen temperature (94%) collected in the 2nd and 3rd quartiles. Rest was most the accurate accelerometer-based traits (89%), and meal duration (87%) and bunk visit (BV) frequency (82%) were the most accurate feeding behavior traits. Rumen temperature collected in the 3rd quartile signaled the earliest (2.5 d) of all the variables monitored with the Shewhart, followed by BV frequency (2.8 d), meal duration (2.8 d), DMI (3.0 d), and rest (4.0 d). Rumen temperature and DMI remained the most accurate variables in the CUSUM at 80% and 79%, respectively. Meal duration (58%), BV frequency (71%), and rest (74%) were less accurate when monitored with the CUSUM analysis. Furthermore, signal day was greater for DMI, rumen temperature, and meal duration (4.4, 5.0, and 3.7 d, respectively) in the CUSUM compared to Shewhart analysis. These results indicate that Shewhart and CUSUM charts can effectively identify deviations in feeding behavior, activity, and rumen temperature patterns for the purpose of detecting sub-clinical BRD in beef cattle.     

Oral administration of Lactobacillus plantarum and Bacillus subtilis on rumen fermentation and the bacterial community in calves

The objective of this study was to assess the effect of dietary probiotics on rumen fermentation and the bacterial community in dairy calves. Twelve Holstein calves were randomly allocated to three treatments: a basal diet, the basal diet supplemented with Lactobacillus plantarum GF103 (LB) or basal diet supplemented with a mixture of Lactobacillus plantarum GF103 and Bacillus subtilis B27 (LBS). A milk replacer was fed to calves from 8 days of age. A starter and alfalfa hay was offered ad libitum from 21 and 28 days of age, respectively, and the orts were weighted daily. The ruminal fluid was sampled at 56 and 83 days of age to determine the rumen fermentation characteristics. The bacterial community was analyzed by denaturing gradient gel electrophoresis (DGGE) and the number of certain bacteria was quantified by real‐time polymerase chain reaction. The ratio of total dry matter intake to average body wieght was higher in the control (P < 0.05). The DGGE fingerprint of the 16S ribosomal RNA gene was affected by the blended probiotics at 83 days of age. The number of Ruminococcus albus was lower in the LB and LBS treatment (P < 0.05). Oral administration of the probiotics affected the rumen bacterial community and the numbers of cellulolytic bacteria decreased.     

Effects of Saccharomyces cerevisiae supplementation on growth performance,plasma metabolites and hormones,and rumen fermentation in Holstein calves during pre‐ and post‐weaning periods

This study aimed to evaluate the effects of supplementing Saccharomyces cerevisiae (SC) during the pre‐ and post‐weaning periods on growth, metabolic and hormonal responses, and rumen fermentation in calves. Three‐week‐old Holstein calves were assigned to either control (n = 12) or SC group (n = 12), the latter of which received 2 × 10⁹ cfu/day of SC. The experiment was conducted over a period of 7 weeks around weaning. Daily gain (DG) in the SC group was higher (p < .05) than that in the control group. In the SC group, plasma glucose, insulin, and growth hormone (GH) concentrations were higher (p < .05) and concentrations of glucagon and insulin‐like growth factor 1 (IGF‐1) tended to be higher (p < .1) than in the control group. Proportion of rumen propionate and concentration of rumen ammonia nitrogen at 10 weeks of age were greater (p < .05) in the SC group than that in the control group. Supplementation of SC around weaning may improve dietary nutrient and energy availability and increase plasma GH and IGF‐1 concentrations. These changes observed in SC‐supplemented calves could be closely related to the improvement of DG.     

Economic loss due to treatment of bovine respiratory disease in Japanese Black calves arriving at a backgrounding operation in Miyazaki

The present study assessed the economic loss due to treatment of bovine respiratory disease (BRD) in Japanese Black calves that were introduced to a backgrounding operation from the age of 3 to 4 months until the age of 10 months. The data collected from a backgrounding operation in Miyazaki, Japan included the records of 2,690 animals entering the farm from 2013 to 2018. The treatment duration was defined as the number of days from the beginning to end of treatment. The cost of treatment was defined as the total cost of treatment during the treatment duration. The average incidence of BRD was 54.6%, and the relative frequency of calves that had BRD once, twice, and three or more times until they left the farm was 64.4%, 26.8%, and 8.8%, respectively (total recorded diagnoses of BRD: 2,494). Among the 2,494 recorded diagnoses, the average and median duration of treatment of BRD was 5.9 days and 3.0 days, respectively. The average and median cost of treatment was 7,767 and 5,600 Japanese yen, respectively. A prolonged duration of treatment and high cost of treatment were associated with BRD relapse, steers, and early stage of production (P<0.05). At the studied farm, the total cost of treatment during the 6-year study period was 19,658,988 yen, and the annual cost was approximately 3 million yen. In summary, the present study showed that BRD had a large economic impact in this backgrounding operation.     

Duration of immunity of a quadrivalent vaccine against respiratory diseases caused by BHV-1, PI3V, BVDV, and BRSV in experimentally infected calves

Several laboratory studies assessed the duration of immunity of a quadrivalent vaccine (Rispoval™4, Pfizer Animal Health) against bovine respiratory diseases (BRD) caused by bovine herpes-virus type-1 (BHV-1), parainfluenza type-3 virus (PI₃V), bovine viral-diarrhoea virus type 1 (BVDV), or bovine respiratory syncytial virus (BRSV). Calves between 7 weeks and 6 months of age were allocated to treatment and then were injected with two doses of either the vaccine or the placebo 3 weeks apart. Six to 12 months after the second injection, animals were challenged with BHV-1 (n = 16), PI₃V (n = 31), BVDV (n = 16), or BRSV (n = 20) and the course of viral infection was monitored by serological, haematological (in the BVDV study only), clinical, and virological means for ≥2 weeks. Infection induced mild clinical signs of respiratory disease and elevated rectal temperature in both vaccinated and control animals and was followed by a dramatic rise in neutralising antibodies in all treatment groups. Titres reached higher levels in vaccinated calves than in control calves after challenge with BHV-1, BVDV, or BRSV. On day 3 after PI₃V challenge, virus shedding was reduced from 3.64 log₁₀ TCID₅₀ in control animals to 2.59 log₁₀ TCID₅₀ in vaccinated animals. On days 6 and 8 after BRSV challenge, there were fewer vaccinated animals (n = 2/10 and 0/10, respectively) shedding the virus than control animals (n = 8/10 and 3/10, respectively). Moreover, after challenge, the mean duration of virus shedding was reduced from 3.8 days in control animals to 1 day in vaccinated animals in the BVDV study and from 3.4 days in control animals to 1.2 days in vaccinated animals in the BRSV study. The duration of immunity of ≥6 months for PI₃V, BHV-1 and BVDV, and 12 months for BRSV, after vaccination with Rispoval™4, was associated mainly with enhanced post-challenge antibody response to all four viruses and reduction of the amount or duration of virus shedding or both.