C.S. Petersson-Wolfe

The effect of meloxicam on pain sensitivity, rumination time, and clinical signs in dairy cows with endotoxin-induced clinical mastitis

The objectives of this study were to (1) evaluate the use of a pressure algometer and an automated rumination monitoring system to assess changes in pain sensitivity and rumination time in response to endotoxin-induced clinical mastitis and (2) evaluate the effect of the nonsteroidal antiinflammatory drug meloxicam on pain sensitivity and rumination time, as well as other clinical signs, in dairy cattle with endotoxin-induced clinical mastitis. Clinical mastitis was induced in 12 primiparous and 12 multiparous lactating dairy cows by intramammary infusion of 25 µg of Escherichia coli lipopolysaccharide (LPS) into 1 uninfected quarter. Immediately after, half the cows were injected subcutaneously with meloxicam (treated group) and half with the same volume of a placebo solution (control group). Pain sensitivity was assessed by measuring the difference in pressure required to elicit a response on the control and challenged quarter using an algometer 3 d before, immediately before, and at 3, 6, 12, and 24h after LPS infusion and either meloxicam or placebo injection. Rumination was continuously monitored from 2 d before to 3 d after LPS infusion using rumination loggers. Udder edema, body temperature, somatic cell score, and dry matter intake were also monitored to evaluate the occurrence and the duration of the inflammation after LPS infusion. In control animals, the difference in the pressure applied to the control and challenged quarters (control - challenged quarter) increased by 1.1 ± 0.4 kg of force 6h after LPS infusion compared with the baseline, suggesting an increase in pain sensitivity in the challenged quarter. Neither the LPS infusion nor the meloxicam treatment had an effect on daily rumination time. However, the rumination diurnal pattern on the day of LPS infusion showed an overall deviation from the baseline pattern. Cows spent less time ruminating in the hours following LPS infusion and more time ruminating later in the day. Meloxicam did not alter somatic cell score or dry matter intake. However, meloxicam-treated animals had less udder edema and a lower body temperature in the hours following LPS infusion compared with control animals. In conclusion, pressure algometers and rumination loggers show promise as tools to detect mastitis and monitor recovery on farm. Further, meloxicam has a beneficial effect in relieving pain and decreasing udder edema and body temperature in LPS-induced clinical mastitis.

Assessment and Management of Pain in Dairy Cows with Clinical Mastitis

It is clear that clinical mastitis has severe detrimental effects on the animal and negative economic impacts for dairy producers. However, pain associated with clinical mastitis, generally, is not measured and not treated. Attention to behavioral and physiologic indicators should be used to monitor animal health. New technologies may allow dairy producers to identify clinical mastitis in its very early stages, or even before clinical changes occur. Furthermore, automated measures of activity, such as step counts and lying time, show promise as predictors of clinical problems. These new technologies, in addition to other automated measures, have the potential for improving the screening methods for preclinical mastitis and accurately predicting the onset of a clinical mastitis event. With this opportunity for very early detection of infection, there is a potential for early intervention with NSAID therapy, which may allow for maximum efficacy from its use. Despite which specific NSAID is used, it is clear that the benefits on temperature, rumen function, SCC, milk production, behavior, and pain sensitivity in animals during mastitis indicate that this therapy has a role throughout the dairy industry. As the health and well-being of dairy cattle continue to be scrutinized by consumer groups, it is essential that the alleviation of any perceived pain or discomfort associated with clinical mastitis should be addressed.

The effects of experimentally induced Escherichia coli mastitis and flunixin meglumine administration on activity measures, feed intake, and milk parameters

The use of flunixin meglumine (FM), a nonsteroidal antiinflammatory drug, during experimentally induced Escherichia coli mastitis was evaluated. Twenty-four primiparous and multiparous lactating dairy cows were challenged with 1×10(2) cfu of E. coli 727 in 1 uninfected quarter. Of the 24 E. coli-challenged animals, 12 were administered FM [ECF; 100mg (2 cc)/45.5 kg of body weight) at the onset of clinical mastitis signs. The remaining 12 challenged cows were untreated (EC). An additional 11 cows were infused with 1 mL of sterile phosphate-buffered saline and served as the nonchallenged control (CTL) group. Activity measures, dry matter intake (DMI), milk production, milk bacterial counts from challenged mammary glands, and somatic cell score (SCS) were collected on all animals. Activity measurements were collected using both a behavior-monitoring system and data loggers. Activity was summarized by day (behavior-monitoring system) and in 3-h time periods (data loggers). An examination of animal activity indicated that EC and ECF cows stood more and lay less as compared with the CTL animals in the first 6h after FM administration. When DMI was analyzed, CTL and ECF animals had greater DMI than the EC animals on d 1 postchallenge. However, by d 2 postchallenge, DMI for ECF and EC cows was significantly less than for the CTL cows. The ECF cows had greater milk yield than did EC animals by d 3 and 4 postchallenge, and no significant difference in yield was observed between the ECF and CTL animals. No differences in SCS were observed between the parity groups. Yet, bacterial counts in milk were greater in multiparous animals compared with the primiparous cows. Therefore, it can be concluded that E. coli mastitis does alter animal activity and may have a negative effect on animal well-being. However, the improvement in DMI and milk production for ECF animals provides evidence for using a nonsteroidal antiinflammatory drug as supportive therapy in alleviating the adverse effects associated with E. coli mastitis.

Short communication: Evaluation of confirmatory stains used for direct microscopic somatic cell counting of sheep milk

Current FDA regulatory screening and confirmatory methods, electronic cell counting and the direct microscopic somatic cell count (DMSCC), differ for the detection of abnormal milk in sheep and goats. The DNA-specific electronic SCC screening methods such as Fossomatic (Foss, Hillerød, Denmark) can be used for both sheep and goat milk; however, the nonspecific methylene blue-based stains used for DMSCC in sheep cannot be used for goats as they nonspecifically stain cytoplasmic particles naturally present in goat milk. The DNA-specific stain pyronin Y-methyl green (PMG) is currently used for DMSCC in goats. Sheep also shed cytoplasmic particles during the milk secretory process, but in fewer numbers than goats. The objective of this study was to determine whether the nonspecific, methylene blue-based Levowitz-Weber (L-W) stain is the appropriate regulatory stain to use for DMSCC in sheep milk. Composite milk samples from 42 commercial dairy ewes were collected every 4 wk for the duration of each ewes lactation for a total of 10 sample days. Milk samples were subjected to 3 methods of SCC determination: automated Fossomatic counting, DMSCC with L-W stain, and DMSCC with PMG stain conducted according to FDA regulatory procedures (2400 series forms). The DMSCC from milk smears stained with L-W were greater than those from smears stained with PMG and those from the Fossomatic analysis on 6 of the 10 sampling days. Milk smears stained with PMG did not differ from Fossomatic analysis at any sampling. The average milk SCC for L-W, PMG, and Fossomatic were (mean±SE) 275±36×10(3), 174±24×10(3), and 164±24×10(3) cells/mL, respectively. The DMSCC for milk stained with L-W was 58% greater than that with PMG and 68% greater than that obtained with the Fossomatic analysis. In conclusion, DMSCC of sheep milk stained with the nonspecific, methylene blue L-W stain resulted in a marked increase in SCC over that of the DNA-specific stain PMG and Fossomatic SCC analysis. The findings of this study support the continued use of Fossomatic SCC but recommend the replacement of the methylene blue-based stains with DNA-specific PMG for determination of DMSCC in sheep milk.

Effect of feeding whole compared with cell-free colostrum on calf immune status: The neonatal period.

Mortality and decreased weight gain resulting from infection and disease in dairy calves are problems within the dairy industry. The bovine neonate relies solely on colostrum to acquire antibodies through passive transfer. To date, colostrum quality is determined by the concentration of antibodies. However, proteins and cells in the colostrum might also enhance immune development in the neonate. To determine the effect of maternal colostral immune cells on calf health and immune status, maternal colostrum was fed either fresh or after lysis of cells by flash-freezing in liquid nitrogen. Thirty-seven female Holstein and Jersey dairy calves were fed 4 quarts total of whole colostrum (WC) or cell-free colostrum (CFC) at birth. Respiratory and fecal scores were measured from birth to d 45 of life. Calf peripheral blood samples were obtained before and after feeding colostrum as well as on d 1, 3, 7, 14, 21, and 28 of life. Peripheral blood mononuclear cells were collected and analyzed for cellular parameters by flow cytometry. Total respiratory scores were greater in CFC-fed calves compared with WC-fed calves on d 38 of life. There were fewer CD4+ T cells and CD4+CD62L+CD45RO- T cells on d 1 and fewer CD4+CD62L+CD45RO+ T cells on d 1 and 3 in CFC-fed calves compared with WC-fed calves. Compared with WC-fed calves, CFC-fed calves had a greater percentage of CD4+CD62L-CD45RO+ T cells on d 0.25, 1, 3, and 7, and a greater percentage of monocytes on d 7. Our data suggest that colostral cells adoptively transfer and enhance neonatal immunity during the first month of life.

Short communication: Analysis of immune function in lactating dairy cows fed diets varying in phosphorus content

The aim of this study was to evaluate the effect of varying dietary P on bovine immune function. Nine first- or second-lactation Holstein cows were fed diets varying in P in a 3 x 3 Latin square design. Diets were formulated to contain either low (0.34%, no supplementary P), medium (0.43%), or high (0.52%) P. All 3 diets were formulated to meet or exceed current NRC requirements for P content. Between d 21 and 26 of each period, blood samples were collected and serum inorganic P concentration, lymphocyte proliferation, and neutrophil bactericidal activity were measured. Serum P increased with increasing dietary P intake and was greatest in the first lactation compared with subsequent lactations. There was a stage of lactation-dependent increase in lymphocyte proliferation after stimulation with concanavalin A, phytohemagglutinin, or pokeweed mitogen. However, dietary P did not alter lymphocyte proliferation or neutrophil bactericidal activity in vitro. In conclusion, decreasing dietary P to reduce manure P content and the risk of P losses from farms to surface water does not have an adverse effect on the innate or cell-mediated immune responses of lactating dairy cattle.

Serum and Synovial Fluid Serum Amyloid A Response in Equine Models of Synovitis and Septic Arthritis

OBJECTIVE To investigate the serum and synovial fluid serum amyloid A (SAA) response in equine models of synovitis and septic arthritis and to compare handheld and validated immunoturbidometric assays for SAA quantification. STUDY DESIGN Controlled, experimental study. ANIMALS Healthy adult horses (n = 9). METHODS Synovitis (n = 4) and septic arthritis (n = 5) were induced using lipopolysaccharide and Staphylococcus aureus, respectively, and serial serum and synovial fluid samples were collected. Serial synovial fluid cytology was performed for both models and synovial fluid from the septic arthritis model was submitted for bacterial culture. Serum and synovial fluid SAA were quantified by handheld test and immunoturbidometric assay. Cytologic and SAA data were compared within and between models (mixed model ANOVA) and results of SAA assays were compared using category-by-category analysis (weighted kappa coefficient). RESULTS Synovial fluid total nucleated cell counts and total protein increased significantly following induction of both models. Serum and synovial fluid SAA remained normal in synovitis horses and increased significantly in septic arthritis horses. Serum SAA increased more rapidly than synovial fluid SAA. Agreement was 98% when SAA concentrations were low (<50 μg/mL) but the assays diverged when concentrations were greater than ∼100 μg/mL. Overall, there was good category-by-category agreement between SAA assays (weighted kappa = 0.824). CONCLUSION Serum and synovial fluid SAA may be useful adjuncts in diagnosing septic arthritis in horses. SAA concentrations for the assays diverged and examination using a larger sample size is needed before direct numeric comparisons between the assays can be made.

Technical note: The use of an accelerometer for measuring step activity and lying behaviors in dairy calves

Calf behaviors such as step activity, lying bouts, and lying time may be an indicator of calf health and welfare. To reduce time-consuming visual observations, the use of behavioral monitoring systems have been developed to capture these data. Previous studies have validated lying behaviors using an accelerometer (HPG; HOBO Pendant G data logger, Onset Computer Corp., Bourne, MA) in calves. However, the HPG does not measure step activity. The objectives of this study were to (1) validate step activity, lying bouts, and lying time of AfiTag II (AT2; AfiTag II, Afimilk Ltd., Kibbutz Afikim, Israel) to observations from video, and (2) to compare the behavioral data from AT2 to the HPG. Calves (n=5) were group housed with an automatic calf feeder. Video cameras were installed at both sides of the pen, and observations were analyzed for 7h/calf. The AT2 and the HPG were both attached to the lateral side of the right rear leg of 5 calves, and data were recorded for 10 d. The full 10-d data set was used to examine correlations for lying bouts and lying time between AT2 and the HPG. The HPG was set at a 60-s sampling interval and the output was analyzed both unfiltered as well as utilizing a 1-min event filter to remove potentially erroneous readings. The AT2 recorded step activity, lying bouts, and lying time, and summarized these behaviors in 15-min periods. The AT2 recorded lying time in 3-min intervals, which were then automatically summarized in 15-min periods. The correlations of step activity, lying bouts, and lying time between video recordings and AT2 were 0.99. For the second objective, correlations between AT2 and the HPG were 0.99 for lying time and 0.93 for lying bouts. The 1-min event filter resulted in a 0.03 improvement in correlations for lying bouts between the HPG and AT2. The high correlation between video recordings and AT2 suggest that this device can be used to measure step activity, lying time, and lying bouts in unweaned dairy calves housed in groups.

Effect of feeding whole compared with cell-free colostrum on calf immune status: Vaccination response.

Vaccination contributes to improved herd health and production. Boosting immune development at a young age may have long-term effects by enhancing vaccine immune response and efficacy. In the bovine, colostrum is the sole source of maternal immunity, having a substantial effect on health status in the neonate. To date, colostral antibody concentration is used to evaluate colostrum quality. However, colostrum also contains proteins and cells, which may affect immune development and future responses to vaccines. To determine the effect of maternal colostral cells on immune development, 37 female Holstein and Jersey dairy calves were bottle-fed 4 quarts total of whole colostrum (WC) or cell-free colostrum (CFC) at birth. Calves were vaccinated with 2 series of multivalent vaccines. Series A consisted of vaccines given between 1 and 4mo of life. Series B consisted of vaccines given between 5 and 10mo of life. Calf peripheral blood samples were obtained before each vaccination series and monthly for 3mo after each vaccination series. Cellular blood parameters were determined by flow cytometry. Quantitative real-time PCR was used to determine cytokine gene expression in peripheral blood mononuclear cells before vaccination series B and once a month for 2mo after vaccination series B. Calves fed CFC had fewer numbers of B cells in mo 2 after vaccination series A when compared with WC-fed calves. Calves fed CFC had decreased gene expression levels of IL-2 in mo 1 and numbers of CD4(+)CD62L(+)CD45RO(-) and CD4(+)CD62L(+)CD45RO(+) T cells in mo 0 and 1 after vaccination series B as compared with WC-fed calves. Our findings indicate a greater response to vaccines up to 6 to 10mo post-WC feeding when compared with CFC. These data suggest that adoptive transfer of maternal colostral cells at birth has a long-term effect on development of the neonatal immune system.

Short communication: comparison of virulence factors in Klebsiella pneumoniae strains associated with multiple or single cases of mastitis.

Klebsiella pneumoniae mastitis in dairy cattle is generally due to an opportunistic infection from the environment, resulting in large heterogeneity among mastitis-causing strains within a herd. However, in mastitis outbreaks in 4 herds, several strains of K. pneumoniae were identified as the cause of infection in multiple cows, suggesting increased ability to either cause disease or evade host defenses. In this study, differences in capsule formation and immune evasion were compared in 5 pairs of K. pneumoniae strains, where one strain in each pair was associated with multiple cases of mastitis and the other with a single case of mastitis. Production of capsular polysaccharide, ability to evade killing by polymorphonuclear neutrophilic leukocytes (PMNL), and the relationship between the 2 were evaluated for each strain grown in broth or milk. Growth of isolates in skim milk increased capsule size and ability to evade killing by PMNL, depending on strain type. Specifically, strains associated with multiple cases of mastitis had increased capsule size in skim milk. Strains associated with single cases of mastitis were better able to evade killing by PMNL when grown in skim milk. Our results, although preliminary, suggest that the 2 groups of strains may constitute different subpopulations of K. pneumoniae. However, our findings do not indicate that capsule or evasions of killing by PMNL explain increased mastitis outbreaks with Klebsiella. Further work will explain the enhanced ability of some strains to cause mastitis in dairy cows.