Nathalie C. Newby

Passive Integrated Transponder (PIT) Tagging Did Not Negatively Affect the Short-Term Feeding Behavior or Swimming Performance of Juvenile Rainbow Trout

Abstract Passive integrated transponder (PIT) tagging is a commonly used procedure to identify fish. However, there is a lack of research on the short-term effects of such tagging. The purpose of our study was to measure the short-term effects of PIT tagging on the feeding behavior and swimming performance of juvenile rainbow trout Oncorhynchus mykiss. Three experiments were conducted. The treatment groups in the first two experiments consisted of a control group and a PIT-tagged group. In the first experiment, we timed the latency to resume feeding before and after the experimental day in fish trained to feed with a light cue. In the second experiment, we recorded the amount of food ingested before and after the experimental day in fish that had been fed to satiation every day for a week prior to the experiment. We found no significant differences between control and PIT-tagged groups for either the latency to resume feeding (time from providing food to food intake) or the amount of food eaten. The third...

Effects of meloxicam on milk production, behavior, and feed intake in dairy cows following assisted calving

Parturition is a necessary event for production in dairy cattle, and assistance at calving is common. There is limited use of nonsteroidal antiinflammatory drugs for the alleviation of calving pain and a paucity of research on the effects of these drugs on postpartum health and performance. This randomized triple blind clinical trial involved Holstein cows (n=42) and heifers (n=61) that experienced an assisted parturition. These animals received either 1 injection of meloxicam (0.5mg/kg of body weight) or placebo subcutaneously 24h following calving. Outcome measures included dry matter intake (DMI) and milk production for the first 14d in milk, blood metabolites sampled over 12d, health events for the first 60d in milk, as well as lying and feeding behavior 24h following injection. Continuous data were analyzed using multivariable regression models. Binary outcomes were analyzed using a mixed logistic model with cow modeled using a random intercept. This study failed to show any significant effects of treatment on DMI, milk production, blood metabolites, or health events. A possible explanation for the lack of treatment differences could be that the meloxicam was administered too late after calving. Meloxicam increased feeding time as well as bunk visit frequency in the 24h following injection. Regardless of treatment, animals that had retained fetal membranes produced less milk and had higher serum haptoglobin concentrations. Future research is warranted to examine the effects of antiinflammatory drugs administered closer to the time of calving on health and production.

Short communication: Use of a mechanical brush by Holstein dairy cattle around parturition

Grooming is a normal behavior that may contribute to relief of stress. The purpose of this study was to investigate the effect of access to a mechanical brush on auto-grooming behavior in parturient cows. The hypothesis was that cows would increase the total time spent scratching using the brush if they had access to a brush around the time of calving, whereas auto-grooming would be lower for the brush group compared with the no-brush group. The use of a mechanical brush was analyzed both in a group-housed pen (72 to 48 h before calving) and in an individual maternity pen (6h before to 6h after calving) in 16 multiparous Holstein cows. In the maternity pen, cows were randomly assigned to have access to the brush or not. The provision of a mechanical brush in the individual maternity pen did not change the amount of time spent auto-grooming but cows did use the brush before calving and after the calf was removed. Despite being housed in pens containing a brush, cows failed to use it when the calf was present. However, cows with access to a brush spent more time licking their calves in the first hour postcalving (β=8.7 min; 95% confidence interval: 1.5, 15.8) than cows that did not have access to a brush. Regardless of treatment, cows increased the time spent auto-grooming and scratching following separation of their newborn calf (β=1.4 min; 95% confidence interval: 0.46, 2.3 and β=0.07 min; 95% confidence interval: 0.02, 0.12, respectively). Further research is warranted to investigate possible benefits of mechanical brush devices at the time of calving, particularly for cows that experience difficult calving and require manual or mechanical assistance.

Factors associated with survival in the herd for dairy cows following surgery to correct left displaced abomasum

Left displaced abomasum (LDA) is a common problem in dairy cows. There have been numerous studies focused on predicting prognosis for right displaced abomasal corrective surgery, but a paucity of studies exist focused on more common LDA surgeries. Our objective was to determine if survival to 60 d or 1 yr after surgery could be predicted from the physical exam findings, periparturient disease status, and a biochemical profile from a blood sample obtained at the time of LDA diagnosis. Blood β-hydroxybutyrate (BHBA) concentrations were measured immediately using a hand-held meter. Data obtained from CanWest DHI (Guelph, ON, Canada) for all of the study subjects (n=179 cases, by 24 veterinarians from 4 clinics), including cull date, cull reason, and test-day milk production. Cows were classified based on whether or not they were culled within 60 d or 1 yr of surgery. Based on logistic regression, cows that had dystocia [odds ratio (OR)=13, 95% confidence interval (CI)=7-26] or were not ketotic (blood BHBA<1.2 mmol/L; OR=3, 95% CI=1.03-9) at the time of corrective surgery were more likely to be culled within 60 d. Higher serum concentrations of BHBA (OR=0.95, 95% CI=0.92-0.98), nonesterified fatty acids (OR=0.81, 95% CI=0.75-0.88), and Mg (OR=0.49, 95% CI=0.35-0.68) all had a protective effect against culling within 1 yr of LDA surgery. Based on survival analysis, longevity in the herd for 365 d following corrective surgery was associated with higher BHBA and Mg at the time of LDA diagnosis before surgery, as well as milk production following surgery.

Short communication: A comparison of 2 nonsteroidal antiinflammatory drugs following the first stage of a 2-stage fistulation surgery in dry dairy cows

Postoperative pain and its management following fistulation surgery in cattle are poorly understood. The purpose of this study was to compare 2 nonsteroidal antiinflammatory drugs (NSAID) as potential postoperative pain management treatments following the first stage of a 2-stage fistulation surgery. A randomized complete block design trial was conducted in dry Holstein cows (n=10) following fistulation surgery. Ketoprofen (3mg/kg of body weight i.m.) was administered on the day of surgery and 24 h later, whereas meloxicam (0.5 mg/kg of body weight s.c.) was administered once only on the day of surgery. Outcomes evaluated at 0, 2, 9, 24, 26, and 33 h postsurgery were heart rate, respiration rate, rectal temperature, and infrared temperature around the surgical site. Outcomes evaluated on the day of surgery and d 1 following surgery and compared with the average for the 4d before surgery were lying activity (total lying time, total time spent lying on the left side, and percentage of time lying on the left side) and feed intake. A difference was observed in dry matter intake on d 1 but this effect was not different on d 0 compared with presurgical averages. A difference was observed in time spent lying on the left side and a difference was observed in heart rate following the first stage of fistulation surgery compared with presurgical averages. The infrared temperature readings around the surgical site were significantly greater in the hours following surgery compared with presurgical averages. The respiration rate increased over time after 24h postsurgery compared with presurgical values. Although it was clear that the surgery is painful, the drug effects were more difficult to explain. On d 0 and 1, the meloxicam-treated cows ate 3 kg more but spent 101 min/d less time lying on their left side compared with ketoprofen-treated cows. The first stage of a 2-stage fistulation surgery was considered painful based on changes in heart rate, respiration rate, infrared temperature readings, dry matter intake, and time spent lying on the left side. It is clear that left flank surgery is painful and that NSAID can improve outcomes associated with that pain, but we cannot make recommendations as to which NSAID to choose based on these results.