The objective of the research was to investigate the effect of Saccharomyces cerevisiae supplementation on some acute-phase proteins, haptoglobin and all electrophoretic parameters in young Charolaise bulls.

Introduction: This article presents the analysis of the correlation between the category and health status of calves and the results of their rearing and levels of selected blood parameters.Material and Methods: The study included 105 Polish Holstein-Friesian and beef (Limousine, Charolaise and Hereford) crossbred calves. Young bulls were purchased at the age of two to four weeks. The animals underwent quarantine, were dehorned, and 46 young bulls were castrated. The germ horns were removed by burning out. Castration was carried out with a bloodless method using a rubber band. The calves were kept in groups and fed a milk replacer administered via teats from automated milk-feeding stations. After the period of milk feeding, the calves were fed grass silage ad libitum and a concentrate at 2.5 kg/animal/day. The calves were weighed every two weeks. Blood for analyses was sampled at 43 d of age.Results: After the rearing period finished at the age of six months, young bulls and steers had similar body weights (176.17 and 176.55 kg) and approximate average daily weight gains from birth (0.756 and 0.767 g/day). The healthy calves at six months of age weighed 180.47 kg, whereas the animals which at least once suffered from some diseases during rearing were lighter by approx. 30 kg (P ≤ 0.01). A statistically significant (P ≤ 0.01) difference was found for the count of red blood cells and white blood cells. In comparison with healthy individuals, the diseased animals had less RBC (8.33 and 9.42 10¹²/L respectively) and more WBC (27.03 and 12.26 10⁹/L respectively).Conclusion: Castration of young bulls did not have any impact on the results of rearing and health status of the calves. The magnitude of the analysed parameters depended on the health status of the calves. Thus RBC and WBC parameters may be used to predict the health status of calves during rearing.

OBJECTIVE To compare the plasma pharmacokinetics of tulathromycin between 3-week-old (preweaned) and 6-month-old (weaned) calves and to characterize the distribution of tulathromcyin into pulmonary epithelial lining fluid (PELF) and interstitial fluid (ISF) of preweaned and weaned calves following SC administration of a single dose (2.5 mg/kg). ANIMALS 8 healthy 3-week-old and 8 healthy 6-month-old Holstein steers. PROCEDURES A jugular catheter and SC ultrafiltration probe were aseptically placed in the neck of each calf before tulathromycin administration. Blood, ISF, and bronchoalveolar lavage fluid samples were collected at predetermined times before and after tulathromycin administration for quantification of drug concentration. A urea dilution method was used to estimate tulathromycin concentration in PELF from that in bronchoalveolar lavage fluid. Tulathromycin–plasma protein binding was determined by in vitro methods. Plasma pharmacokinetics were determined by a 2-compartment model. Pharmacokinetic parameters and drug concentrations were compared between preweaned and weaned calves. RESULTS Clearance and volume of distribution per fraction of tulathromycin absorbed were significantly greater for weaned calves than preweaned calves. Tulathromycin–plasma protein binding was significantly greater for weaned calves than preweaned calves. Maximum PELF tulathromycin concentration was significantly greater than the maximum plasma and maximum ISF tulathromycin concentrations in both groups. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that age affected multiple pharmacokinetic parameters of tulathromycin, likely owing to physiologic changes as calves mature from preruminants to ruminants. Knowledge of those changes may be useful in the development of studies to evaluate potential dose adjustments during treatment of calves with respiratory tract disease.

OBJECTIVE To investigate the effects of meloxicam administration before long-distance transport on inflammatory mediators and leukocyte function of cattle at feedlot arrival. ANIMALS 60 healthy yearling beef steers. PROCEDURES Single-source steers were assigned to a transported (n = 40) or nontransported (20) group. Then, half of the steers within each group were assigned to receive meloxicam (1 mg/kg, PO) or a lactose placebo (1 bolus/steer, PO). All steers were transported approximately 1,300 km overnight to a feedlot; however, the nontransported group was moved before treatment (meloxicam or placebo) administration and allowed a 17-day acclimation period, whereas the transported group was moved immediately after treatment administration on day −1. Blood samples for measurement of inflammatory mediators and leukocyte function were collected from all steers on days −1, 0, and 3. RESULTS For steers that received meloxicam, mean plasma meloxicam concentration for the transported group was significantly greater than that for the nontransported group on day 0. For steers that received the placebo, mean haptoglobin-matrix metalloproteinase-9 complex for the transported group was significantly greater than that for the nontransported group on day 0. Mean haptoglobin concentration, neutrophil L-selectin intensity, and polymorphonuclear leukocyte count for the transported group were significantly greater than those for the nontransported group. Mean substance P concentration for nontransported steers that received meloxicam was significantly lower than that for the other 3 treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated meloxicam administration to healthy steers immediately before long-distance transport did not significantly mitigate the effects of transport-induced stress on leukocyte function or inflammatory markers.

Objective: To characterize clinical and behavioral changes in calves following inoculation with Mycoplasma bovis and evaluate relationships between those changes and pulmonary disease. Animals: 22 healthy Holstein steers. Procedures: 20 calves were inoculated intranasally with < 10(8) CFU or > 10(9) CFU of M bovis. Calves were assigned a clinical illness score (CIS) on a scale of 1 through 4 twice daily on the basis of severity of cough, labored breathing, and lethargy. For each calf, distance traveled and time spent near the waterer, feed bunk, or shelter were determined via a remote location monitoring device. Calves were euthanized and necropsied 22 days after inoculation. Results: 13 calves became clinically ill after challenge inoculation; 3 calves were euthanized within 20 days. Among all calves, consolidation was evident in 0% to 79.9% of the lungs; extent of lung consolidation did not differ between the challenge dose groups. Distance traveled and percentages of time spent in proximity to the feed bunk and shelter were associated with CIS; calves with more severe disease traveled less distance and spent less time at the feed bunk and more time in the shelter. Distance traveled by calves was negatively associated with extent of lung consolidation (< or ≥ 10% of lungs affected); this effect was modified by trial day. Conclusions and Clinical Relevance: Following inoculation with M bovis, calf behavior patterns were associated with both CIS and severity of pulmonary disease. Use of behavior monitoring systems may aid in recognition of respiratory tract disease in calves.

Objective—To evaluate serum haptoglobin concentration at feedlot arrival and subsequent performance and morbidity and mortality rates of calves that developed bovine respiratory disease. Animals—360 heifer calves and 416 steer and bull calves. Procedures—Serum samples were obtained from cattle at the time of arrival to a feedlot (day −1) and analyzed for haptoglobin concentration. In experiment 1, calves were classified into groups with a low (< 1.0 μg/mL), medium (1.0 to 3.0 μg/mL), or high (> 3.0 μg/mL) serum haptoglobin concentration and allotted into pens on the basis of group. In experiment 2, calves were classified as having or not having detectable serum haptoglobin concentrations. Results—In experiment 1, average daily gain from days 1 to 7 decreased as haptoglobin concentration increased. Dry-matter intake (DMI) from days 1 to 21 decreased with increasing haptoglobin concentration, and DMI typically decreased from days 1 to 63. Total bovine respiratory disease morbidity rate typically increased with increasing haptoglobin concentration. At harvest, no differences in carcass characteristics were observed on the basis of haptoglobin concentration. In experiment 2, cattle with measureable serum haptoglobin concentrations at arrival weighed less throughout the experiment, gained less from days 1 to 7, and had lower DMI from days 1 to 42. Overall morbidity rate was not different between groups, but cattle with detectable serum haptoglobin concentrations had higher odds of being treated 3 times. Conclusions and Clinical Relevance—Serum haptoglobin concentration in cattle at the time of feedlot arrival was not associated with overall performance but may have limited merit for making decisions regarding targeted prophylactic treatment.

Objective - To evaluate the effectiveness of various sampling techniques for determining antimicrobial resistance patterns in Escherichia coli isolated from feces of feedlot cattle. Sample Population - Fecal samples obtained from 328 beef steers and 6 feedlot pens in which the cattle resided. Procedure - Single fecal samples were collected from the rectum of each steer and from floors of pens in which the cattle resided. Fecal material from each single sample was combined into pools containing 5 and 10 samples. Five isolates of Escherichia coli from each single sample and each pooled sample were tested for susceptibility to 17 antimicrobials. Results - Patterns of antimicrobial resistance for fecal samples obtained from the rectum of cattle did not differ from fecal samples obtained from pen floors. Resistance patterns from pooled samples differed from patterns observed for single fecal samples. Little pen-to-pen variation in resistance prevalence was observed. Clustering of resistance phenotypes within samples was detected. Conclusions and Clinical Relevance - Studies of antimicrobial resistance in feedlot cattle can rely on fecal samples obtained from pen floors, thus avoiding the cost and effort of obtaining fecal samples from the rectum of cattle. Pooled fecal samples yielded resistance patterns that were consistent with those of single fecal samples when the prevalence of resistance to an antimicrobial was > 2%. Pooling may be a practical alternative when investigating patterns of resistance that are not rare. Apparent clustering of resistance phenotypes within samples argues for examining fewer isolates per fecal sample and more fecal samples per pen.

The effects of subcutaneous administration of a commercially available estradiol 17 beta implant on hematologic values and the chemiluminescence response of neutrophils were evaluated in 14 steers. Chemiluminescence and hematologic values were measured in treated (n = 8) and nontreated (n = 6) steers on days -14, -7, and -1 prior to implantation. Estradiol 17 beta was implanted into the treated group of steers on day 0, and blood samples were obtained from all steers on days 1, 2, 3, 4, 8, 15, 22, 29, 36, 43, and 50. The concentration of estrogen in serum was significantly (P = 0.0120) higher following implantation. Chemiluminescence and hematologic indices were not significantly affected by either implant status or serum concentrations of estrogen. The results of this study suggested that the use of implants containing estradiol 17 beta for promotion of weight gain in steers will not result in alterations of hematologic values or the neutrophil respiratory burst.

Hepatic abscesses were induced experimentally in 5 steers by inoculating Fusobacterium necrophorum via ultrasonography-guided, percutaneous catheterization of the portal vein. Hepatic ultrasonography was performed to determine the onset and progression of abscessation. Blood samples were collected before and after inoculation for performing leukocyte counts and hepatic function tests. Ultrasonographic evidence of liver abscesses was observed as early as 3 days after inoculation. Abscesses appeared as hyperechoic centers (cellular debris and pus) surrounded by hypoechoic or anechoic areas (fluid). Increases in rectal temperature, leukocyte counts, fibrinogen, globulin, bilirubin, gamma-glutamyltransferase, and sorbitol dehydrogenase concentrations were detected. Hepatic dysfunction was evidenced by decrease in serum albumin concentration and low sulfobromophthalein clearance. The ultrasonographic diagnosis of abscesses correlated well with necropsy findings.

A group of 48 crossbred steers (approx 250 kg each) were used to determine the effects of various diets and treatments on serum prolactin concentrations and rectal temperatures. The steers were randomly assigned to groups fed the following: (1) endophyte fungus-infested fescue hay; (2) ammoniated endophyte fungus-infested cattle industry hay; (3) endophyte fungus-infested fescue hay plus 1 g of thiabendazole (TBZ)/9.1 kg of body weight at 7-day intervals; (4) ammoniated endophyte fungus-infested fescue hay plus 1 g of TBZ/9.1 kg at 7-day intervals; (5) ground Bermuda grass hay; and (6) endophyte-fungus-free fescue hay. Blood samples for prolactin determinations and rectal temperatures were obtained biweekly beginning on week 3 and continuing through week 9. A significant correlation (P < 0.05) between low prolactin concentrations and high rectal temperatures in cattle eating endophyte-infested fescue hay was determined; however, as the prolactin concentrations approached normal (control animal) concentrations, this relationship between serum prolactin and rectal temperatures was not observed. Two antifungal agents used in this experiment (thiabendazole and ammonia) appeared to have different effects on the variables measured. Thiabendazole had no significant effect on prolactin concentrations or rectal temperatures of cattle ingesting endophyte-infested fescue hay, whereas ammoniation of this hay induced significantly higher (P<0.05) prolactin concentrations and lower rectal temperatures than in steers receiving only endophyte-infested fescue hay. Therefore, ammonia may be valuable not only as an aid in determining the cause of the fescue problem but also as a practical solution to some of the fescue-related economic problems in the cattleindustry. Also, prolactin concentrations may be valuable in diagnosing fescue-related problems.