Dale A. Moore

Field Trial Evaluating the Influence of Prophylactic and Therapeutic Antimicrobial Administration on Antimicrobial Resistance of Fecal Escherichia coli in Dairy Calves

ABSTRACT The objective of this study was to describe the influence of in-feed and therapeutic antimicrobials on resistance in commensal fecal Escherichia coli isolated from preweaned calves. Four groups of 30, day-old calf-ranch calves were enrolled and raised until 4 weeks of age. Groups 1 to 3 were raised without antimicrobials in the feed. Group 1 was isolated from the other groups and received no antimicrobial therapy. Group 2 was housed on the calf ranch and did not receive antimicrobial therapy, whereas groups 3 and 4 could be treated with antimicrobials. Group 4 was fed neomycin and tetracycline HCl in the milk replacer. Fecal samples were collected from calves on days 1, 14, and 28. Three E. coli isolates per sample were evaluated for susceptibility to 12 antimicrobials. Cluster analysis was used to group isolates having similar susceptibility patterns. Cumulative logistic regression was used to evaluate factors associated with increasing levels of multiple antimicrobial resistance. In-feed antimicrobials were associated with higher levels of multiple antimicrobial resistance in fecal E. coli.f In calves not receiving in-feed antimicrobials, older calves had higher levels of resistance compared to day-old calves. Individual antimicrobial therapy increased resistance in these calves but appeared to be transient. There was no environmental influence on resistance in E. coli populations among study groups.

Evaluation of the effects of oral colostrum supplementation during the first fourteen days on the health and performance of preweaned calves.

Abstract Increasing concerns about antimicrobial resistance have led to the development and implementation of alternatives to antimicrobial use in animal production. The objective of this clinical trial was to determine the effect of colostrum supplementation of the milk replacer ration on morbidity, mortality, feed intake, and weight gain of preweaned calves. Ninety 1-d-old calves on each of 3 commercial calf ranches were randomly allocated to 1 of 3 groups. Treatment-group calves received 10g of supplemental immunoglobulin G (IgG) in the form of 70g of colostrum powder in the milk replacer twice daily for 14 d. The placebo-group calves received a nutritionally equivalent supplement lacking IgG in the milk replacer twice daily for 14 d. Control calves received milk replacer without supplements twice daily. Calves were housed in individual hutches and were weighed on d 1, 28, and 60. Serum was collected on d 2 for serum IgG determination. Daily health evaluations for the first 28 d of life were performed by study personnel blinded to treatment group assignment. Observed illness was treated based on health assessment, rectal temperature, and specific calf ranch protocols. Feed consumption (milk and grain) was recorded. Calves receiving supplemental colostrum had less diarrhea and received fewer antimicrobial treatments than control and placebo calves. The results indicated that calf diarrhea was associated with low serum IgG levels and low-weight calves. Grain consumption and weight gain over the first 28 d of life were significantly greater in colostrum-supplemented calves compared with control calves. No differences in mortality or respiratory disease incidence among groups were detected. Supplemental colostrum during the first 2 wk of life can reduce diarrheal disease in preweaned calves on calf ranches and thereby reduce the amount of antimicrobial treatments needed.

Comparison of published recommendations regarding biosecurity practices for various production animal species and classes

OBJECTIVE To compare published recommendations regarding biosecurity practices for various production animal species and classes. DESIGN Literature review. POPULATION Educational materials available on the World Wide Web that provided biosecurity recommendations for dairy cattle, beef cattle, small ruminant, swine, and poultry producers. PROCEDURES Web sites for national producer organizations, university cooperative extension services, and state departments of agriculture were searched to identify educational materials with biosecurity recommendations. RESULTS A single national organization was selected as representing each animal agriculture commodity group. A total of 53 university Web sites were visited, and 65 publications prepared by university cooperative extension services were identified and evaluated. Web sites for all 50 state departments of agriculture were searched, and 29 were found to have at least 1 publication related to biosecurity practices, for a total of 46 publications. Evaluation of the biosecurity recommendations revealed wide variations by source and within and among commodity groups. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that educational materials for producers contained wide variations in recommended biosecurity practices. It is possible that some producers choose not to implement biosecurity recommendations because of confusion as to the specific recommendations they should follow.

Targeting therapy to minimize antimicrobial use in preweaned calves: Effects on health, growth, and treatment costs

Prophylactic and therapeutic antimicrobial use in food animals is questioned because of the potential for development of resistant bacteria and future inability to use some antimicrobials for human or animal disease. The objectives of this study were to determine the effect of raising preweaned dairy calves without antimicrobials in the milk and minimizing therapeutic antimicrobial treatment on morbidity, mortality, weight gain, and treatment costs. Newborn calves (n = 358) were allocated to 1 of 4 groups, housed outdoors in individual hutches, and monitored for 28 d. Calves in the conventional therapy (CT) group were treated as per dairy protocol with sulfamethoxazole/trimethoprim, spectinomycin, penicillin, and bismuth-pectin for diarrhea. The targeted therapy (TT) group included bismuth-pectin for diarrhea and antimicrobial treatment only in cases of fever or depressed attitude. Within CT and TT groups, calves were equally assigned to receive neomycin and tetracycline in their milk for the first 2 wk of life (AB-milk) or no antimicrobials (NoAB-milk). Daily health evaluations included fecal consistency, respiratory disease, attitude, and hydration status as well as milk and grain consumption. A negative binomial model evaluated the total number of days with diarrhea days in each group. General linear models were used to assess average daily weight gain and grain consumption. Conventionally treated calves had 70% more days with diarrhea than TT calves, and AB-milk calves had 31% more days with diarrhea compared with NoAB-milk calves. The TT calves tended to have a higher average daily gain by 28 d and consumed more grain compared with CT calves. If antimicrobials were used only for diarrhea cases with fever, inappetence, or depression and no in-milk antimicrobials were used, a

Associations among serum pro- and anti-inflammatory cytokines, metabolic mediators, body condition, and uterine disease in postpartum dairy cows

10 per calf savings could be realized. Targeting antimicrobial therapy of calf diarrhea cases is prudent not only to save the drugs for future use but also to prevent the potential for antibiotic-associated diarrhea and reduce calf-rearing costs.

Factors associated with the rectal temperature of Holstein dairy cows during the first 10 days in milk.

BackgroundAdipose tissue is an active endocrine organ which secretes a wide range of hormones and protein factors, collectively termed adipokines. Adipokines affect appetite and satiety, glucose and lipid metabolism, inflammation and immune functions. The objectives were to evaluate serum concentrations of adipokines (adiponectin, leptin, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6) in lactating dairy cows with postpartum uterine inflammatory conditions (metritis, clinical endometritis or subclinical endometritis) and in cows experiencing loss of body condition, and to assess the relationship of adipokines and body condition loss in the establishment of persistent uterine inflammatory conditions.MethodsLactating multiparous Holstein cows (N = 40), with body condition scores (BCS) from 2 to 4 (eight cows for each 0.5 score increment) were enrolled. Body condition was monitored for all cows weekly for 7 weeks post calving; cows with uterine inflammatory conditions were also re-evaluated 2 weeks later. Blood samples were collected from 1 week prior to calving to 7 weeks after calving for determination of serum concentrations of adipokines, insulin and insulin like growth factor (IGF)-1.ResultsCows with metritis or clinical endometritis had higher serum concentrations of adiponectin, leptin, TNF-alpha, IL-1beta and IL-6 compared to normal cows (P < 0.05). Furthermore, serum leptin, TNF-alpha, IL-1beta and IL-6 were higher in cows with subclinical endometritis compared to normal cows (P < 0.05), and insulin and IGF-1 concentrations were lower in cows with metritis or clinical endometritis. Cows with low BCS (2 and 2.5) had significantly higher adiponectin, TNF-alpha, IL-1beta and IL-6 than those with high BCS (3 to 4). Cows with persistent uterine inflammatory conditions had higher adiponectin, leptin TNF-alpha, IL-1beta and IL-6 and insulin compared to normal and spontaneously recovered cows, except for IGF-1 (P < 0.05).ConclusionsSerum concentrations of adipokines, insulin, and IGF-1 had significant associations with BCS categories (low vs. high) and postpartum uterine inflammatory conditions. Perhaps loss of body condition mediated increases in anti- and pro-inflammatory cytokines, whereas increased pro- and anti-inflammatory cytokines concentrations mediated body condition loss and thereby prolonged persistence of uterine inflammation in dairy cows.

Outbreak of malignant catarrhal fever among cattle associated with a state livestock exhibition

Daily evaluation of rectal temperature (RT) during the first 10 d in milk (DIM) is used to facilitate the early identification of postpartum complications, particularly metritis in dairy cows. The factors associated with RT of postpartum dairy cows have not been clearly established and the RT threshold used to define fever has been variable. The objectives were to identify factors associated with the RT of postpartum dairy cows and provide descriptive statistics of the RT during the first 10 DIM to clarify the normal range of RT for cows. Daily RT was evaluated from 1 to 10 DIM for all cows calving during 2 consecutive summers on a single 1,500-cow Holstein dairy. Cows were placed into metabolic/digestive (METB), infectious (INF), and no recorded disease (NONE) groups based on disease diagnoses during the first 10 DIM. Cows were grouped based on calving difficulty and parity. Multiple linear regression models with repeated measures were used to evaluate the factors associated with RT. Three hundred and ninety-two cows were evaluated, of which 45% were primiparous and 32% required assistance at calving. No difference was observed in calving assistance by parity. First disease diagnoses peaked in the INF and METB groups at 3 and 1 DIM, respectively. The RT of primiparous cows was 0.1 to 0.2°C higher than that of multiparous cows from 1 to 8 DIM, accounting for calving difficulty, twin births, month of calving, and disease group in the model. The INF group cows had a higher RT than did NONE group cows (38.9±0.04 to 39.2±0.73 vs. 38.7±0.03°C, respectively) on each of the first 10 DIM, which was approximately 0.6°C higher from 3 to 5 DIM. The RT of cows with metritis was at least 0.1°C higher (38.8±0.05°C) than that of NONE group cows beginning 4 d before diagnosis. The mean RT of primiparous, defined healthy (NONE group) cows was 38.8±0.02°C, with an upper normal limit (mean+2 SD) of 39.6°C. The mean RT of multiparous cows in the NONE group during the first 10 DIM was 38.7±0.01°C, with an upper normal limit of 39.5°C. The RT of dairy cattle during the first 10 DIM was associated with parity, month of calving, and an infectious disease diagnosis, particularly the diagnosis of metritis. The normal RT of dairy cattle in the immediate postpartum period, during the warm summer months, is potentially higher than that generally reported.

Effects of one versus two doses of prostaglandin F2alpha on AI pregnancy rates in a 5-day, progesterone-based, CO-Synch protocol in crossbred beef heifers.

CASE DESCRIPTION Severe disease and death were identified in cattle exhibited at a state fair that were naturally infected with ovine herpesvirus type 2 (OvHV-2). CLINICAL FINDINGS Most affected cattle had anorexia, signs of depression, diarrhea, fever, and respiratory distress ultimately leading to death. Mean duration of clinical signs prior to death was 6 days (range, 1 to 26 days). Mean number of days between apparent exposure and death was 71 days (range, 46 to 139 days). TREATMENT AND OUTCOMES 19 of 132 cattle cohoused in 1 barn died of malignant catarrhal fever (MCF). The diagnosis of sheep-associated MCF was confirmed on the basis of results of an OvHV-2-specific PCR assay performed on tissue samples obtained from affected cattle. The disease was associated but not significantly with distance from the center of the barn and was not associated with distance from the center of the sheep pens. CLINICAL RELEVANCE Outbreaks of MCF in cattle are unusual, particularly in association with livestock exhibitions. Because the clinical signs may be similar to those of some transboundary diseases, cases of MCF should be reported and investigated. Findings for this outbreak provided evidence to suggest that fair boards and veterinarians should reexamine biosecurity recommendations for livestock exhibitions.

Recent Emergence of Escherichia coli with Cephalosporin Resistance Conferred by blaCTX-M on Washington State Dairy Farms

The present study determined whether a 5-d progesterone-based CO-Synch protocol with a single dose of prostaglandin F(2α) (PGF) at progesterone withdrawal on Day 5, would yield a timed AI pregnancy rate similar to two doses of PGF given 6 h apart on Day 5. Angus cross beef heifers (N = 562) at six locations were used. All heifers received 100 µg of gonadorelin hydrochloride (GnRH) and a controlled internal drug release (CIDR) insert on Day 0. Within farm, heifers were randomly allocated to receive one dose of 25 mg dinoprost (PGF) at CIDR removal on Day 5 (1 PGF; N = 264), or two doses of 25 mg PGF, with the first dose given on Day 5 at CIDR removal, and the second dose 6 h later (2 PGF; N = 298). Most heifers (N = 415) received a heat detector patch at CIDR removal. After CIDR removal, heifers were observed twice daily through Day 7 for estrus and heat detector aid status was recorded. On Day 8, heifers were given 100 µg of GnRH, heat detector aid status was recorded, and heifers were inseminated approximately 72 h after CIDR removal. Accounting for significant variables such as location (P < 0.01), heifers in estrus at or prior to AI (P < 0.001), and a treatment by location interaction (P < 0.01), two doses of PGF on Day 5 tended to have higher pregnancy rates to timed AI compared to those that received one dose of PGF (P = 0.06). In conclusion, heifers given two doses of PGF at CIDR removal on Day 5, in a 5-d CIDR-CO-Synch protocol, tended to have a higher pregnancy rate than those that received only one dose of PGF.

Comparison of modeled sampling strategies for estimation of dairy herd lameness prevalence and cow-level variables associated with lameness

ABSTRACT Enterobacteriaceae-associated bla CTX-M genes have become globally widespread within the past 30 years. Among isolates from Washington State cattle, Escherichia coli strains carrying bla CTX-M (CTX-M E. coli strains) were absent from a set of 2008 isolates but present in a set of isolates from 2011. On 30 Washington State dairy farms sampled in 2012, CTX-M E. coli prevalence was significantly higher on eastern than on northwestern Washington farms, on farms with more than 3,000 adult cows, and on farms that recently received new animals. The addition of fresh bedding to calf hutches at least weekly and use of residual fly sprays were associated with lower prevalence of CTX-M E. coli. In Washington State, the occurrence of human pathogens carrying bla CTX-M genes preceded the emergence of bla CTX-M-associated E. coli in cattle, indicating that these resistance determinants and/or their bacterial hosts may have emerged in human populations prior to their dissemination to cattle populations.