Impact of oral meloxicam and long-distance transport on cell-mediated and humoral immune responses in feedlot steers receiving modified live BVDV booster vaccination on arrival.

The objective of this study was to investigate the impact of oral meloxicam (MEL) and long-distance transportation on cell-mediated immunity (CMI) in preconditioned steers receiving a booster vaccination on arrival. We hypothesized that steers treated with MEL at 1mg/kg body weight, 6h before night-time transport, would be less immunocompromised on arrival (day 0) and after 7days, and that CMI following vaccination with a modified live bovine viral diarrhea virus (BVDV) recall antigen would be increased. Brahman crossbreed steers, 13-17 months of age (n=87), were randomly assigned to one of four treatment groups: MEL, transported (MTR) (n=22), MEL, non-transported (MNT) (n=22), lactose placebo, transported (CTR) (n=21), and lactose placebo, non-transported (CNT) (n=22). MTR and CTR steers were transported for approximately 16h non-stop on a truck from Mississippi to Iowa (approximately 1300km), whereas steers in the MNT and CNT groups remained in Mississippi as non-transported controls. Body weight was measured and jugular blood was collected at -1, 0, and 7days from all steers at the same time, regardless of location. Multi-parameter flow cytometry (MP-FCM) was used to identify T-cell subsets and detect the expression of three activation markers (CD25 [interleukin (IL)-2 receptor], intracellular interferon-gamma [IFNγ], and IL-4) after in vitro stimulation with BVDV recall antigen. Plasma cortisol concentration was measured on day -1, 0, and 7 as a marker of transport-associated stress. Serum antibody titer to BVDV was assessed on day -1 and day 7 post-booster vaccination. Whole-blood samples were analyzed using MP-FCM on days 0 and 7. Results were log transformed and analyzed using repeated measures of analysis of variance. Compared with non-transported controls, transport led to an increase in BVDV-induced expression of CD25, IFNγ, and IL-4 in CD4(+), CD8(+), and γδ(+) T-cell subsets (P<0.05). MEL treatment mitigated the transportation-associated increase in CD25 expression by peripheral blood mononuclear cells (PBMCs), CD4(+), and γδ(+) T cells. CMI outputs for the MTR group were less than those of the CTR group (P<0.05); however, the MTR and NT groups did not differ (P>0.10). A treatment*transport interaction was noted for the increase in IL-4 expression by CD8(+) T cells after transport, with a significant difference between the CTR and MTR groups at day 7. In conclusion, the use of oral MEL prior to transport appears to have inhibitory or homeostatic effects, but further research is needed to validate the effect of MEL treatment on specific T-cell subsets in transported cattle.

A critical review and meta-analysis of the magnitude of the effect of anthelmintic use on stocker calf production parameters in Northern US States.

Parasitism of the gastrointestinal tract of cattle leads to diminished health and productivity of grazing livestock. Anthelmintics are used to decrease parasite loads in cattle for improved weight gain. This critical review and meta-analysis aims to quantify the magnitude of the effect of use of anthelmintic products on production metrics in beef stocker calves. Four databases were searched in March 2013. Eligible studies compared average daily gain (ADG), or weight gain in stocker calves in northern climates of the United States that received anthelmintic treatments compared with placebo or an alternative anthelmintic treatment. Study results were extracted, and where possible, summary effect measures were calculated. Of 512 citations identified by the search, 9 manuscripts with 23 relevant individual studies were selected. Risk of bias was assessed for all studies included in the review and assessed to be unclear for the majority of the studies. There were 23 studies that assessed the magnitude of effect of anthelmintic use on ADG (summary mean difference in ADG=0.05 kg (50 g), 95% CI=0.03-0.07 kg, p<0.00001). The magnitude of weight gain associated with anthelmintic use could not be assessed, as measures of precision (standard errors or standard deviations) were not reported in these studies. Overall, the conclusion was made that anthelmintic use is associated with an increased weight gain. However, the approach to reporting employed by authors for this type of study means that many studies could not be included in the meta-analysis and the magnitude of effect not determined.

Impact of oral meloxicam on circulating physiological biomarkers of stress and inflammation in beef steers after long-distance transportation.

Transportation stress can result in significant economic losses to producers due to decreased animal productivity and increased medication costs associated with sickness such as bovine respiratory disease (BRD). Meloxicam (MEL) provides pain relief and anti-inflammatory effects in cattle for several days after a single oral treatment. Our hypothesis was that MEL administration before shipping would reduce the impact of long-distance transportation on circulating physiological biomarkers of stress and inflammation in beef steers. Ninety-seven beef steers were blood sampled for baseline biomarker determination and then randomly assigned to receive either 1 mg/kg MEL (n = 49) or a placebo (CONT; n = 48) per os before a 1,316-km transportation event lasting approximately 16 h. Calves were then blood sampled on arrival and 5 d later. Changes in the hemogram, circulating plasma proteins, total carbon dioxide (TCO2), fibrinogen, substance P (SP), cortisol, haptoglobin (Hp)-matrix metalloproteinase-9 (MMP-9) complexes, and tumor necrosis factor α (TNFα) between treatments over time were compared using a mixed effects model with statistical significance designated as P < 0.05. Analysis of covariance was conducted to assess the relationship between circulating MEL concentrations and biomarker changes over time. An increase in neutrophil, platelet, monocyte, white blood cell, and red blood cell counts occurred after transportation (P < 0.0001) and a decrease in lymphocyte count were observed (P < 0.0001). Meloxicam treatment reduced the stress-induced neutrophilia (P = 0.0072) and circulating monocyte count (P = 0.013) on arrival. Mean corpuscle hemoglobin (P = 0.05), mean corpuscle volume (P = 0.05), and lymphocyte count (P = 0.05) were also greater in the CONT calves compared with MEL calves after transportation. Furthermore, Hp-MMP-9 complexes, TCO2, TNFα, plasma proteins, and SP increased and cortisol decreased after shipping (P < 0.01). Meloxicam treatment tended to reduce serum cortisol concentrations (P = 0.08) and there was evidence of a time × treatment interaction (P = 0.04). An inverse relationship between plasma MEL concentrations and circulation cortisol concentrations (P = 0.002) and neutrophil (P = 0.04) and basophil counts (P = 0.03) was also observed. The results suggest that MEL administration may reduce the impact of long-distance transportation on circulating physiological biomarkers of stress and inflammation in beef calves.

A randomized clinical trial evaluating a farm-of-origin autogenous Moraxella bovis vaccine to control infectious bovine keratoconjunctivis (pinkeye) in beef cattle.

BACKGROUND: A randomized, masked, 2-arm parallel trial was conducted to assess the efficacy of a Moraxella bovis (M. bovis) autogenous vaccine to prevent naturally occurring infectious bovine keratoconjunctivis (IBK) in beef calves. HYPOTHESIS: The null hypothesis was that treatment group was not associated with either risk of IBK or last observed weight. ANIMALS: The trial was conducted between May and November 2009 and 2010 on a university-owned farm in Iowa. The vaccine contained 2 randomly selected M. bovis from IBK cases that occurred at the farm in 2008. Calves born between January and May 2009 and 2010 without visible corneal lesions were randomly allocated to receive vaccine (n = 191) or placebo (n = 178). METHODS: Two s.c. doses were administered 21-28 days apart. Allocation to treatment was concealed using bottles marked A or B. Staff observing the animals for IBK could not determine the treatment grouping. The herd met the "at-risk" criteria (ie, >15% IBK in unvaccinated calves and M. bovis detection in IBK cases). Analysis was "per-protocol". RESULTS: The risk of IBK was 58/185 (31%) in vaccinated calves and 66/173 (38%) in unvaccinated calves (adjusted risk ratio = 0.78; 95% CI, 0.49-1.24). Average weight before sale did not differ between the vaccinated calves (196.6 kg, SD ± 39.9) and unvaccinated calves (198.1 kg, SD ± 42.7) (P value = .19). No adverse effects were noted. CONCLUSION AND CLINICAL IMPORTANCE: Combination of the study results with previous studies suggests that autogenous M. bovis vaccines often are ineffective in controlling naturally occurring IBK.

A randomized and blinded field trial to assess the efficacy of an autogenous vaccine to prevent naturally occurring infectious bovine keratoconjunctivis (IBK) in beef calves.

A randomized and blinded 2-arm parallel trial was conducted to assess the efficacy of an autogenous vaccine to prevent naturally occurring infectious bovine keratoconjunctivis (IBK) in beef calves. The trial was managed between May and November 2008 on university owned farms in Iowa and Wisconsin. The vaccine at Iowa contained Moraxella bovoculi (M. bovoculi) while the organism used in the Wisconsin herds vaccine was Branhemella ovis (B. ovis renamed M. ovis). Calves born between January and May 2008 without visible corneal lesions were randomized to receive an autogenous vaccine or placebo vaccine using a computer generated sequence. Two subcutaneous doses were administered 21-28 days apart. Allocation to treatment was concealed using bottles marked A or B. Staff were blind to the treatment allocation. The primary outcome was IBK cumulative incidence over the study period. The secondary outcome was weaning weight. Only the Iowa herd met the criteria for an "at-risk" herd i.e. >15% IBK in unvaccinated calves and M. bovoculi isolation from IBK cases. Analysis was "per-protocol". The cumulative incidence of IBK was 47/105 in vaccinated calves and 49/109 in unvaccinated calves (unadjusted odds ratio=0.99, 95% CI: 0.58-1.70). Weight at weaning did not differ between the vaccinated cohort 148kg (SD: +/-27) and unvaccinated cohort 146kg (SD: +/-26) (unadjusted beta=1.5 and 95% CI: -5.5 to 8.6). Results indicate that the autogenous vaccine was ineffective in this study population.

The development of beef breeding bulls.

Management of the bull battery will have a dramatic impact on profitability of the cow/calf enterprise. It is critical that young bulls be selected and developed to maximize longevity and productivity for the eventual buyer. Bulls must be structurally sound, healthy, and have adequate libido in order to service the required number of females. Once bulls complete their first breeding season, special care must be taken in order to ensure that they recover and regain needed body condition and pass a bull breeding soundness examination (BBSE). Mature bulls that have reached their genetic potential for growth require less intensive management, but the health program and annual BBSE cannot be overlooked. Mature bulls are also more likely to carry venereal disease and should be screened according to local disease incidence and state regulations. All bulls, regardless of age, should be observed early during the breeding season to ensure that they are physically capable of mounting and servicing females. The establishment of a complete management program, especially for young bulls, is essential to ensure that ranch resources are used efficiently, including maintenance of a high level of reproductive performance of the cow herd.

Developing replacement beef heifers.

The replacement heifer represents the next generation of genetic progress for the cow herd. Producers invest a substantial amount of capital in these females, even if they fail to become pregnant. In order to get a return on this investment, it is imperative that these heifers become pregnant early in the first breeding season, calve with a minimum of dystocia, breed back in a timely fashion, and then continue to be productive for a number of years. Practitioners working with heifer development programs need to emphasize a systemic approach that evaluates these females at critical times. These programs need to address such areas as weaning and nutritional management, genetic selection, prebreeding evaluation, the breeding season, and heifer management from pregnancy examination through the end of their first calving season. This increased level of scrutiny should not end until the heifer weans her first calf and is determined to be pregnant the second time. This type of program will ensure optimal reproductive rates, female longevity, and a positive return on the producer's investment.

Persistent activity of doramectin injectable formulation against experimental challenge with Haemonchus placei in cattle.

Two studies were conducted in North America to evaluate the persistent activity of doramectin injectable formulation against experimental challenge with Haemonchus placei. In both studies, calves were randomly assigned to 1 of 4 treatment groups (n = 10 per group) or a larval viability group (n = 2). Calves were treated subcutaneously in the lateral midline of the neck with saline (1 ml/50 kg) on Day 0, or with doramectin (200 mg/kg = 1 ml/50 kg) on Day 0, 7, or 14. Animals used to assess larval viability did not receive any treatment. Beginning on Day 14 and continuing through Day 28, each of the 40 treated calves were given approximately 300 infective larvae of H. placei per os. The two larval viability animals received approximately 10,000 larvae as a single dose on Day 28. Approximately two weeks later, all animals were slaughtered and the abomasum from each calf processed for nematode recovery. A 2% aliquot of abomasal contents plus wash was examined for enumeration and identification of nematodes. Geometric mean H. placei counts were calculated from the log (H. placei count +1) and used to estimate percentage reduction. Overall, doramectin was > or =96.9% efficacious in reducing infection with H. placei when challenged daily 14-28 days after treatment.

Preventative programs for respiratory disease in cow/calf operations.

Control of respiratory disease in cow/calf operations presents many challenges. The incidence of disease in the suckling calf is not well documented and the logistics of handling range animals make control programs difficult to implement. Health programs have to be built around normal working patterns, and these patterns may not provide the best "fit" for immune management of the calf. Weaned calves undergo significant disease challenge when they enter typical marketing channels. This provides the potential for high levels of calf morbidity, mortality, medicine costs, and losses from decreased performance as they arrive at a stocker operation or feedyard. If preweaning calf health and preconditioning programs are used, they must be planned so that the producer has an opportunity to obtain a return on their investment. Options for increasing calf weight marketed, certified calf health sales, or retained ownership through the next phase of production should be evaluated carefully. Any potential increase in calf value must be weighed against program costs. This affords the veterinarian an opportunity to build on traditional disease management and prevention skills and expand their influence in overall ranch management.

Repair of a proximal diaphyseal femoral fracture in a calf, using intramedullary pinning, cerclage wiring, and external fixation.

Repair of a comminuted, spiral oblique, proximal diaphyseal femoral fracture in a 7-day-old calf was achieved by use of an intramedullary pin, cerclage wires, and external fixator. Six stainless steel wires were used for full cerclage to secure a long butterfly fragment and multiple incomplete and complete nondisplaced fragments to the femur in order to create 2 principal fragments. Axial alignment and resistance to bending was provided by a round, double-pointed, end-threaded intramedullary pin (6.35 mm in diameter), which was inserted in a retrograde fashion. A type-1, double-connecting-bar external fixator, using 4 round pins (4.8 mm in diameter), was used to provide supplemental stabilization against shear and torsional forces. At 45 days after surgery, healing at the fracture site was seen on radiography of the limb, and the external fixator was removed. Eight months after surgery, the calf had a normal gait.

Atlanto-occipital fusion in two polled Hereford calves.

Two cases of atlanto-occipital fusion were diagnosed in Polled Hereford calves. The cause, genetic or environmental, of this abnormality could not be determined. Since relatively minor traumatic forces during birth can cause severe injury in the head region, atlanto-occipital fusion should be ruled out in calves dying acutely after assisted parturition.