Evaluation of horn bud wound healing following cautery disbudding of preweaned dairy calves treated with aluminum-based aerosol bandage.

Pain management during and following disbudding procedures has been studied extensively, though few studies have evaluated wound healing following cautery disbudding in dairy calves. The purpose of this study was to observe wound healing following cautery disbudding with or without treatment using a topical aluminum-based aerosol bandage (ALU) in preweaned dairy calves. Dairy calves were disbudded within the first 3 wk of life using a standard cautery disbudding protocol. The ALU treatment was randomly allocated to the right or left horn bud within each animal. The outcomes measured were lesion score (LS) and wound diameter (WD). The LS was evaluated on a scale of 1 to 3, with LS = 1 representing normal healing without a scab or exudate, LS = 2 having the presence of a scab, and LS = 3 showing the presence of wound exudate. Lesion score and WD were evaluated on a weekly basis following dehorning for 3 wk. A total of 209 animals completed the study. No difference was observed in LS between groups during the first 2 wk postdisbudding, but the proportion of LS = 3 on wk 3 postdisbudding was greater for the control group when compared with ALU (17 vs. 8%, respectively). During wk 1 and 2 postdisbudding, the odds of having delayed healing, or a LS ≥2, were similar for both groups. However, the odds tended to be different at wk 3 postdisbudding with control disbudding sites being 1.42 times more likely to have delayed healing than ALU. In wk 3, WD was 1 mm smaller in the treatment group compared with the control, and treatment decreased diameter over time compared with controls. Overall, once abnormal wound healing was observed, the likelihood of having abnormal wound healing the following week was increased. However, treatment with ALU diminished this effect on delayed healing during the follow-up period. Based on these results, the use of ALU improved wound healing following cautery disbudding of preweaned dairy calves.

Herd management practices and their association with bulk tank somatic cell count on United States dairy operations.

The objective of this study was to evaluate associations between bulk tank somatic cell count (BTSCC) and herd management practices using data collected in the National Animal Health Monitoring System Dairy 2002 study. Twenty-six percent and 17.8% of 1,013 operations reported a BTSCC < 200,000 cells/mL and > 400,000 cells/mL, respectively. Univariate analysis identified associations between management variables and BTSCC. The use of mattresses, sand, and newspaper as bedding were all associated with a lower BTSCC. Primary lactating cow housing facility, outside maternity housing area, flooring type cows walk or stand on, and use of automatic take-offs were also associated with BTSCC. Multivariate associations between management variables and BTSCC were determined by backward elimination ordinal logistic regression. The odds of an operation from the West, Midwest, and Northeast having a high BTSCC were lower than those from the Southeast. The odds of a higher BTSCC were 2 times greater for operations with a rolling herd average milk production < 9,090 kg/cow per year compared with those with > or = 9,090 kg/cow per year. Operations using composted manure were 2.9 times more likely to have a higher BTSCC than those not using composted manure. Finally, operations that reported not using a coliform mastitis vaccine were 1.7 times more likely to have a higher BTSCC than those using one. Future studies of the association between management practices and BTSCC should include an evaluation of the quality of management practice application and herd prevalence of contagious mastitis pathogens. Significant variables identified in this study dealt with housing, use of composted manure for bedding, and coliform mastitis vaccine use, suggesting the effect of environmental mastitis pathogens may be more influential on BTSCC than previously thought.

Short communication: Efficacy of parenteral ceftiofur for treatment of systemically mild clinical mastitis in dairy cattle.

The objective of this study was to evaluate the effect of intramuscular (i.m.) ceftiofur (2.2 mg/kg) on important outcomes of systemically mild clinical mastitis episodes in lactating dairy cattle. Cows with clinical mastitis were randomly assigned to a treatment group: pirlimycin intramammary (i.m.m.) (n = 35), pirlimycin i.m.m. and ceftiofur i.m.m. (n = 36), cephapirin i.m.m. (n = 40), cephapirin i.m. and ceftiofur i.m. (n = 33). Sixty-nine, 22, and 9% of initial cultures were gram-negative, gram-positive, and mixed, respectively. Logistic regression analysis showed no significant associations between treatment groups and loss of quarter, recurrence, or culling. Mixed infections, positive milk culture at 7 d after leaving hospital pen, decreased rumen motility, and absence of udder firmness were associated with increased odds of mastitis recurrence. The results suggest that i.m. ceftiofur treatment has no beneficial effects on the outcome of systemically mild clinical mastitis.

Detection and identification of Mycoplasma from bovine mastitis infections using a nested polymerase chain reaction.

A polymerase chain reaction (PCR) test was compared with culture for the detection and diagnosis of bovine Mycoplasma intramammary infection. The PCR test was applied to 24-hour Mycoplasma enrichment cultures of milk from cows with suspected mastitis and from bulk tank milk. In comparison to culture, the sensitivity and specificity of the PCR method were 96.2% and 99.1% for individual cow milk and 100% and 99.8% for the bulk tank milk, respectively. However, in discrepant cases where PCR was positive and culture was negative, the PCR test was correct; subsequent PCR tests and culturing of the individual cow's milk yielded positive results. The PCR test simultaneously detected and differentiated among 11 bovine Mycoplasma species.

Performance studies of an enzyme-linked immunosorbent assay for detecting Staphylococcus aureus antibody in bovine milk.

An enzyme-linked immunosorbent assay (ELISA) for detecting Staphylococcus aureus antibody in bovine milk samples was examined for repeatability. A set of 51 bovine milk samples from 4 universities with confirmed culture results was assembled, and a panel of 30 milk samples was randomly selected. When the selected panel was tested at the collection laboratory, there was 97% agreement between the ELISA and the culture test. The panel was tested with the ELISA by the 4 university laboratories. Results were scored by both visual and optical density reader methods. When compared to reference ELISA results, the university laboratory ELISA results showed an agreement of 99.8% for negative samples, 98% for positive samples, and 99% for all samples. Additional studies on 19 milk samples that cultured positive for bacteria other than S. aureus showed 100% specificity. Overall comparison of ELISA and culture results showed high agreement between the 2 techniques. Disagreement appeared to result from explainable differences in antibody and bacterial levels and not from errors in either of the 2 techniques.

Malignant catarrhal fever: polymerase chain reaction survey for ovine herpesvirus 2 and other persistent herpesvirus and retrovirus infections of dairy cattle and bison.

Using a polymerase chain reaction (PCR) test for sequences of ovine herpesvirus 2 (OHV2), this virus was shown to be significantly associated with sheep-associated malignant catarrhal fever (SA-MCF) in terminal cases of disease in 34 cattle and 53 bison. Ovine herpesvirus 2 was not detected in cattle (38) and bison (10) that succumbed to other diseases. Other persistent herpesviruses, retroviruses, and pestivirus, some of which have been previously isolated from cases of SA-MCF, were not associated with the disease. These included bovine herpesvirus 4 (BHV4), bovine lymphotrophic herpesvirus (BLHV), bovine syncytial virus (BSV, also known as bovine spumavirus), bovine immunodeficiency virus (BIV), and bovine viral diarrhea virus (BVDV). A PCR survey for OHV2 in DNA from individual cow's peripheral blood lymphocytes in 4 dairies showed that the 1 dairy that was in close contact to sheep had a prevalence of OHV2 of 21.3%, whereas the 3 other dairies had no OHV2. Prevalence of the other herpesviruses and retroviruses in the dairy cows was variable, ranging from 2% to 51% for BHV4, 52% to 78.7% for BLHV, and 10% to 34% for BSV. Bovine lymphotrophic herpesvirus and BSV were also found in a few (1-4 of 21 tested) cases of terminal SA-MCF, but BIV and BVDV were not found in either the dairy cows sampled, or in the cases of SA-MCE No significant correlation was found between the presence of any 2 viruses (OHV2, BHV4, BLHV, BSV) in the dairy cows or terminal cases of SA-MCE

Naturally occurring acute coliform mastitis in Holstein cattle.

Physical examination and clinicopathologic findings from 44 adult Holstein cows with naturally occurring coliform mastitis were studied. The cattle were grouped for comparison by stage of lactation and survival. Cattle within the first 4 weeks of lactation maintained higher median mature neutrophil counts (1,200 versus 300/microL) in peripheral blood than cattle later in lactation. Nonsurviving cows had higher median creatinine concentration (2.5 versus 1.6 mg/dL) and anion gap (25 versus 20 mEq/L), and lower serum protein (7.1 versus 7.6 gm/dL) and total CO2 (19.8 versus 25 mEq/L) concentrations than surviving cows (P < .05). These findings indicate that cattle with uremia and metabolic acidosis are less likely to survive the infection. Bacteriologic blood cultures were performed on 34 of the 44 cows studied. Escherichia coli was isolated from the blood in 11 (32%) cows. Clinical presentation and clinicopathologic data were compared in bacteremic versus nonbacteremic cows to evaluate these data as predictors of bacteremia. Bacteremic cows were sick longer prior to admission (2 versus 1 days), maintained higher median counts of total nucleated cells (6.6 versus 2.4 x 10(3) cells/microL), myelocytes (0.2 versus 0 x 10(3) cells/microL), metamyelocytes (0.5 versus 0.02 x 10(3) cells/microL), band neutrophils (0.7 versus 0.1 x 10(3) cells/microL), and lymphocytes (2.1 versus 1.4 x 10(3) cells/microL) than nonbacteremic cows, and had higher plasma fibrinogen concentration (600 versus 500 mg/dL) (P < .05). There were no differences between the physical or serum biochemical measurements. Four of 11 bacteremic cows and 5 of 23 nonbacteremic cows died or were euthanized (P > .05). The high prevalence of bacteremia seen in cows with coliform mastitis has not been reported previously, and may have been due to the duration of disease, severity of signs, or culture technique. These findings suggest that systemic antibiotic therapy may be beneficial in some severe cases of coliform mastitis.

Treatment of dairy cows at parturition with prostaglandin F2 alpha or oxytocin for prevention of retained fetal membranes.

OBJECTIVE: To evaluate the effects of treatment at parturition with dinoprost tromethamine, fenprostalene, or oxytocin on postpartum disease and reproductive performance during the subsequent breeding season in dairy cows. DESIGN: Prospective study. ANIMALS: 1,400 Holstein cows from 5 commercial dairies. PROCEDURE: Cows were assigned within 2 hours after calving to serve as untreated control cows or to be treated with 1 mg of fenprostalene, SC; 25 mg of dinoprost tromethamine, IM; or 20 IU of oxytocin, IM. Cows were confined to treatment pens and monitored daily until fetal membranes were expelled. Cows with retained fetal membranes (RFM) were treated according to existing treatment protocols for the dairy, with the provision that intrauterine infusions were not allowed. All other disease conditions were recorded, and appropriate treatment was administered. Postpartum reproductive examinations were performed 28 to 56 days after parturition Breeding records were maintained for all cows until pregnancy was confirmed or the cow was removed from the herd. RESULTS: Fetal membranes were retained in 12.1% of all cows, and this outcome was unaffected by treatment. Compared with cows without RFM, cows with RFM had longer intervals to first insemination (76.4 vs 82.0 days), reduced first insemination conception rates (46.8 vs 28.0%), and increased number of days not pregnant (103.2 vs 127.4 days). Farm, as a variable, significantly affected development of RFM and postpartum disease conditions as well as reproductive performance during the subsequent breeding season. Fetal membranes were retained in 12.4, 15.2, 8.7, 6.3, and 16.9% of cows on farms 1, 2, 3, 4, and 5, respectively. Mean days to first insemination varied from 64.5 days (farm 3) to 91.5 days (farm 1). Mean number of days not pregnant varied from 94.8 days (farm 3) to 15.9 days (farm 4). CLINICAL IMPLICATIONS: Administration of prostaglandins or oxytocin at the time of calving does not reduce the incidence of RFM or improve reproductive performance. Farm management practices have the greatest impact on dairy cow performance.

Evaluation of the use of intrauterine infusions of oxytetracycline, subcutaneous injections of fenprostalene, or a combination of both, for the treatment of retained fetal membranes in dairy cows.

Dairy cows (n = 207) that had retained fetal membranes for more than 8 hours after parturition were randomly assigned to 1 of 4 treatment groups (group 1, daily intrauterine infusion of oxytetracycline; group 2, daily intrauterine infusion of oxytetracycline and a single SC injection of fenprostalene; group 3, a single SC injection of fenprostalene; and group 4, untreated controls). Cows were monitored daily. Subsequent disease conditions were recorded, and appropriate treatments were initiated. Interval from parturition to expulsion of fetal membranes was unaffected by treatment regimen. The frequency of cows with high rectal temperatures (> or = 39.5 C) was significantly (P < 0.05) less in cows treated with oxytetracycline infusions; however, the frequency of displaced abomasum, ketosis, and mastitis was unaffected by treatment method. Treatment method appeared to influence the development of postpartum uterine pathologic conditions. Treatment with oxytetracycline and fenprostalene (group 2) increased (P < 0.05) the frequency of pyometra. Treatment with fenprostalene (groups 2 and 3) decreased the number of cows with a palpable uterine lumen detectable during per rectal palpation at 28 to 42 days after parturition. Reproductive efficiency, as determined on the basis of the interval from parturition to conception, was unaffected by treatment protocol.

Oxytetracycline residues in milk after intrauterine treatment of cows with retained fetal membranes.

OBJECTIVE: To establish the maximum concentration and duration of oxytetracycline residues in milk from cows with retained fetal membranes given the antimicrobial via intrauterine infusion, and to investigate whether the number of infusions or the presence of fever (> 39.7 C) affected the duration of residues. DESIGN: Prospective study. ANIMALS: 54 Holstein cows with retained fetal membranes on a single 1,400-cow commercial dairy. PROCEDURE: Cows were treated once a day with 5 g of oxytetracycline (50 ml of 100 mg/ml solution in a povidone base) by intrauterine infusion for at least 2 days, or until the membranes were expelled. Cows that became febrile (rectal temperature > or = 39.7 C) were also given 20,000 IU of procaine penicillin G/kg of body weight, i.m., for 2 to 4 days. Milk samples were collected at 24-hour intervals during treatment. and at 12-hour intervals after the last treatment. All samples were frozen and submitted every 2 weeks for high performance liquid chromatography analysis for oxytetracycline. RESULTS: Oxytetracycline was detected in milk of all cows during treatment, at a maximum concentration ranging from 47.2 to 1,804.6 micrograms/kg (mean, 316.9 micrograms/kg). Duration of oxytetracycline residues after the last infusion ranged from 0 to 144 hours (mean, 52.3 hours). Neither the number of infusions received, nor development of rectal temperature > 39.7 C, affected the maximum concentration or the duration of oxytetracycline residues in milk. CLINICAL IMPLICATIONS: Milk obtained from cows that had been treated for retained fetal membranes by intrauterine infusion of oxytetracycline should be discarded to avoid illegal residues.

Use of systemic disease signs to assess disease severity in dairy cows with acute coliform mastitis.

OBJECTIVE: To evaluate the use of systemic disease signs for classifying severity of acute coliform mastitis in dairy cows. DESIGN: Prospective cohort study. ANIMALS: 144 dairy cows. PROCEDURE: Cows were examined at the time of initial identification of disease (time 0) and classified as having mild, moderate, or severe disease on the basis of rectal temperature, hydration status, rumen contraction rate, and attitude. A CBC and serum biochemical analyses were performed, and milk samples were submitted for bacterial culture at time 0 and 48 hours later. RESULTS: 69 cows were classified as having mild disease, 44 as having moderate disease, and 31 as having severe disease. Median WBC and neutrophil counts were significantly lower in cows with moderate or severe disease at time 0 than in cows with mild disease. Band neutrophil count was significantly higher at 48 hours and serum calcium concentration was significantly lower at time 0 and at 48 hours in cows with severe or moderate disease, compared with cows with mild disease. Twenty-eight, 51, and 77% of cows with mild, moderate, and severe disease, respectively, had > 100,000 colony-forming units/ml of milk at time 0. The odds that a cow with severe disease would die or be culled were 3.6 times the odds for a cow with moderate disease and 11.2 times the odds for a cow with mild disease. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a classification scheme based on readily observable systemic disease signs can be used to classify disease severity in cows with acute coliform mastitis.

Bacteremia associated with naturally occuring acute coliform mastitis in dairy cows.

OBJECTIVE: To determine the incidence of bacteremia in dairy cows with naturally occurring acute coliform mastitis (ACM) with a wide range of disease severity. DESIGN: Cohort study. ANIMALS: 144 dairy cows with ACM from 6 herds. PROCEDURE: Cows were examined at time of identification of ACM (time 0) and classified as having mild, moderate, or severe mastitis on the basis of rectal temperature, hydration status, rumen contraction rate, and attitude. Cows were reexamined at 24 or 48 hours. Bacteriologic culturing of milk and blood (30 ml), CBC, and serum biochemical analysis were performed at each time point. Appropriate samples were obtained at a single point from herdmates without mastitis (controls) that were closely matched for lactation number and days since parturition. Blood culture results were compared among severity groups and controls by use of chi2 tests, as was outcome of an ACM episode for cows grouped by blood bacterial isolates. RESULTS: Bacteria were isolated from 52 blood samples from 46 of 144 (32%) cows with ACM, which was significantly more than control cows (11/156; 7.1%). Group-1 isolates (Escherichia coli, Pasteurella multocida, Mannheimia haemolytica, Klebsiella pneumoniae, Enterobacter agglomerans, and Salmonella enterica serotype Typhimurium) were identified in 20 of 144 (14%) cows with ACM and 0 of 156 control cows. Group-1 isolates were identified in 4.3, 9.1, and 42% of cows classified as having mild, moderate, and severe ACM, respectively. Escherichia coli and K pneumoniae milk and blood isolates obtained from the same cow were of the same genotype. Bacillus spp were identified in 21 of 144 (15%) cows with ACM, which was significantly more than control cows (3/156; 1.9%). Thirty-five percent of cows with a group-1 isolate died during the mastitis episode. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that bacteremia develops in a substantial proportion of cows with ACM. Classification of severity of disease is important for establishment of effective treatment protocols; parenteral antimicrobial treatment may be indicated in cows with ACM.

Bar suture (toggle pin) vs open surgical abomasopexy for treatment of left displaced abomasum in dairy cattle.

Fifty-nine dairy cows with left displacement of the abomasum were randomly assigned to receive 1 of 2 treatments. Twenty-eight were treated by right paramedian abomasopexy via laparotomy, and 31 were treated by percutaneous fixation of the abomasum, using the bar suture or toggle pin technique. Comparisons of the 2 groups, at 4 follow-up examinations, yielded no significant differences in return to normal milk production, return to normal feed intake, mortality, culling rate, tissue reaction at the surgical site, or redisplacement up to 60 days into the subsequent lactation.

Effect of gonadotropin-releasing hormone on clinical response and fertility in cows with cystic ovaries, as related to milk progesterone concentration and days after parturition.

We gave gonadotropin-releasing hormone (GnRH) or an analog of GnRH to 264 lactating cows with cystic ovaries. The effects of milk progesterone concentration (MPC) and days after parturition (DAP) at diagnosis on clinical response 30 days after treatment and on subsequent fertility were examined. Palpation per rectum revealed ovarian cysts in 264 cows; 118 had true follicular cysts (MPC less than 1 ng/ml). Clinicians with more than 3 years of experience reported significantly more true cysts than did less experienced clinicians. Clinical response 30 days after treatment did not differ in 3 groups of cows (divided on the basis of MPC at treatment), but fewer cows with MPC less than 1 ng/ml were bred or conceived than were cows with MPC greater than or equal to 33 ng/ml. Days after parturition at diagnosis did not affect 30-day clinical response rate, but cows treated less than 35 DAP had significantly more days to first estrus and to conception than did cows treated greater than 90 DAP. Significantly more cows treated less than 35 DAP had MPC less than 1 ng/ml at treatment.

An evaluation of simultaneous GnRH and cloprostenol treatment of dairy cattle with cystic ovaries.

In a randomized double-blind clinical trial, 75 cows with ovarian cysts were treated with the synthetic gonadotropin releasing hormone, gonadorelin acetate (GnRH). Forty-two of these cows were simultaneously treated with cloprostenol (CP), and the remaining 33 cows received sterile saline. Milk progesterone (P(4)) was measured at treatment and two days later. Clinical response 30 days after treatment was determined by palpation per rectum, and estrus and breeding dates were recorded up to 90 days after treatment. Cows were examined for pregnancy by palpation per rectum 40 days or more after breeding. Milk progesterone levels two days after treatment were significantly lower and the 30-day clinical response rate was significantly higher in the GnRH + CP group than in the GnRH group. Intervals to first estrus and to conception, proportion in heat by day 21 after treatment, and pregnancy rate by 90 days did not differ significantly between the groups. The same relationships held in a subset of cows with P(4)>/=1 ng/mL at treatment. Fewer cows in the GnRH + CP group became pregnant by day 90 after treatment, but this difference was not significant. These results suggest that simultaneous GnRH and cloprostenol treatment of all cows with cystic ovaries cannot be recommended at this time.

A randomized clinical trial of the effect of the time of administration of cloprostenol on detention of estrus in dairy cattle.

We performed a clinical trial to study whether cows with palpable corpora lutea treated with cloprostenol by the farmer on the morning following examination (median time 0630 hours) were seen in heat and conceived more frequently than cows treated by the veterinarian immediately following the reproductive examination (median time 1210 hours).There were no significant differences between the two groups in the proportions of cows seen in estrus or fertility at the induced estrus.The proportions of animals that had the time of onset of estrus recorded and were seen in estrus during working hours (0800-1600 hours) were also not significantly different between the veterinary-treated and farmer-treated groups.Under the conditions of this study, there was no reason to prefer prescribing early morning administration of cloprostenol by farmers over immediate administration of the drug by the clinician.

Immune-mediated hemolytic anemia induced by penicillin in horses.

Three horses developed severe, immune-mediated hemolytic anemia after treatment with penicillin. The horses had positive direct antiglobulin (Coombs) tests and high titers of IgG antibody that agglutinated penicillin-coated equine red cells. Two of the horses were tested for antibodies to autologous red cell antigens; autoantibodies were not present. Titers of antipenicillin antibody decreased after penicillin was discontinued but IgG antibody was detectable months after recovery. One of the horses was challenged with penicillin; antibody titer increased slightly, but anemia did not develop. Antipenicillin antibody of the IgM class was present in low titer in 23 (77%) of 30 non-anemic horses tested. Apparently, the horse is similar to man in that penicillin-induced anemia is rare but the percentage of individuals with antipenicillin antibody is high.

Effect of milk sample delivery methods and arrival conditions on bacterial contamination rates.

A cross sectional study was performed of factors believed to contribute to the contamination of bovine milk sample cultures submitted to the Ithaca Regional Laboratory of the Quality Milk Promotion Services/New York State Mastitis Control. Of 871 samples entered in the study, 137 (15.7%) were contaminated. There were interactions between the sample source (veterinarian vs dairyman), delivery method, and time between sample collection and arrival at the laboratory. If only those samples collected and hand delivered by the dairyman within 1 day of collection were compared to a like subset of samples collected and hand delivered by veterinarians, no statistically significant differences in milk sample contamination rate (MSCR) were found. Samples were delivered to the laboratory by hand, US Postal Service, United Parcel Service, via the New York State College of Veterinary Medicine Diagnostic Laboratory, or Northeast Dairy Herd Improvement Association Courier. The MSCR was only 7.6% for hand delivered samples, while 26% of Postal Service samples were contaminated. These rates differed significantly from other delivery methods (P less than 0.0001). The USPS samples arrived a longer time after sampling than did samples sent by other routes, and time had a significant effect on MSCR (0 to 1 day, 8.9%; greater than 1 day, 25.9%; P less than 0.01). Samples packaged with ice packs sent by routes other than the Postal Service had a lower MSCR than those not packaged with ice packs, but ice packs did not reduce the MSCR for samples sent by the Postal Service.(ABSTRACT TRUNCATED AT 250 WORDS)