Contents:

Effect of becoming BVD-free in dairy herd

Effect of 4-way viral vaccine for prevention of BRD

Metaphylactic florfenicol for treatment of BRD

Feeding flaxseed during receiving period

Weaning & source impact on performance and BRD
 

Effect of becoming BVD-free in dairy herd

The aim of the study was to investigate the effect of BVDV-free certification of dairy herds on fertility and udder health. Cases were defined as dairy herds that had at least one BVDV-antigen positive animal, subsequently gained the BVDV-free status by participating in the BVDV-control program of the Animal Health Service (AHS) and maintained this status for at least 2 years. Controls had an unknown status for BVDV and two controls were matched to one case by region and herd size. Data concerning fertility and milk production of all herds were provided by The Dutch Royal Cattle Syndicate (NRS). After validation, data of 79,607 cows of 392 case herds and 124,831 cows of 730 control herds were analyzed on ten fertility and three udder health parameters.
For the analyses all observations were aggregated at herd level. To account for the matching, differences for fertility parameters were calculated between each of the two pairs of case–control within a matching code. The analyses were performed with these differences as dependent variables. Mixed models and GEE models were used for the statistical analyses of fertility and udder health.
Case herds had a significantly lower abortion rate in the BVDV-free period than controls herds (10.3% versus 11.6%, P < 0.01) while there was no significant difference for the other fertility parameters. There was no effect on mastitis prevalence or bulk-milk SCC but the mastitis incidence significantly decreased for case herds in the BVDV-free period (cases 0.6 % lower than controls, P < 0.05). In our study the effect of getting the BVDV-free status may have been underestimated for several reasons like an unknown status for control herds, not knowing when an acute infection occurred in case herds and not knowing the management for both cases and controls. Interestingly, both significant variables, being abortions and mastitis incidence, are parameters that are more difficult to influence by the farmer than the other parameters (e.g. calving interval).

Berends, I.M.G.A., W.A.J.M. Swart, K. Frankena, J. Muskens, T.J.G.M. Lam and G. van Schaik The effect of becoming BVDV-free on fertility and udder health in Dutch dairy herds. Preventive Veterinary Medicine Volume 84, Issues 1-2, 17 April 2008, Pages 48-60





Effect of 4-way viral vaccine for prevention of BRD

We investigated the effect of vaccination of male beef calves (mean age ± S.D.: 158 ± 31days) against bovine herpes virus (BHV-1 or IBR virus), bovine respiratory syncitial virus (BRSV), bovine viral diarrhea (BVD) virus and para-influenza (PI3) virus on the incidence of respiratory disease during the first forty days after weaning and entering a feed-lot in Portugal.
In May 2003, Mertolenga, Preta and mixed-breed calves from 10 different beef herds, were systematically assigned (by order of entrance in a chute) to two treatment groups, before moving to a common feed-lot. One hundred and twenty five male calves were vaccinated with a quadrivalent vaccine (Rispoval 4®) and revaccinated after 21–27 days while 148 herdmates were injected with saline (0.9% NaCl) on the same occasions. The incidence and severity of clinical cases of “bovine respiratory disease” (BRD) were evaluated every day during the first 40 days after entering the feed-lot. Morbidity (3% vs. 14%) and mortality (0% vs. 4%) due to BRD were significantly lower in the vaccinated group. Ten days after revaccination, the calves were treated with an antimicrobial – ending the study – after an outbreak of BRD caused a high incidence of disease in the non-vaccinated group.
In conclusion, our results showed that Rispoval 4®, a quadrivalent vaccine against respiratory viruses, under field conditions, reduces morbidity and mortality due to BRD in beef calves after weaning.

Stilwell, G., M. Matos, N. Carolino and M. S. Lima. Short communication: Effect of a quadrivalent vaccine against respiratory virus on the incidence of respiratory disease in weaned beef calves. Preventive Veterinary Medicine Volume 85, Issues 3-4, 15 July 2008, Pages 151-157





Metaphylactic florfenicol for treatment of BRD

The efficacy of an injectable formulation of florfenicol (300 mg/mL) as metaphylactic control of naturally occurring bovine respiratory disease (BRD) was evaluated in two double-blind randomly controlled field studies on two Dutch veal calf herds (A and B). Cattle aged not older than 3 months and in the direct presence of calves with clinical respiratory disease were randomly allocated to treatment with 40 mg/kg florfenicol subcutaneously (s.c.) a positive control treatment (12.5 mg/kg tilmicosin p.o. twice daily for five consecutive days in herd A, and 12.5 mg/kg doxycycline p.o. twice daily for five consecutive days in herd B), or a negative control (one placebo saline s.c. administration on D0). The predominant respiratory pathogens present in pretreatment respiratory samples from affected animals were Mycoplasma bovis and Pasteurella multocida in outbreaks A and B, respectively. Metaphylactic administration of florfenicol resulted in a statistically significant weight gain, decreased rectal temperature for five consecutive days after treatment and decreased metaphylactic failure percentages compared with both positive and negative control groups. In summary, these studies demonstrated that a single s.c. injection of florfenicol is effective and practical for control of the bacterial component of BRD in veal calves.

B. Catry, L. Duchateau, J. Van de ven, H. Laevens, G. Opsomer, F. Haesbrouck, A. de Kruif (2008) Efficacy of metaphylactic florfenicol therapy during natural outbreaks of bovine respiratory disease. Journal of Veterinary Pharmacology and Therapeutics. Online Early Articles doi:10.1111/j.1365-2885.2008.00981.x





Feeding flaxseed during receiving period

Two experiments were conducted at the Kansas State University Beef Cattle Research Center to determine the effects of feeding ground flaxseed (flax) during the receiving period on growth, health, and subsequent finishing performance of heifers. Crossbred heifers (Exp. 1 n = 363, 214 ±1 kg initial BW; Exp. 2 n = 377, 222 ±1 kg initial BW) were purchased during January and April of 2006. Heifers were fed receiving rations based on steam-flaked corn with 0, 2, 4, or 6% ground flax (DM basis) for 56 d. Following the receiving period, cattle in Exp. 1 and 2 were fed steam-flaked corn based diets for 150 d and 147 d, respectively, and then slaughtered. Heifers were implanted 91 and 109 d prior to slaughter, for Exp. 1 and 2, respectively. In Exp. 1, DMI during the receiving period tended to increase linearly (P = 0.09) with increasing flax in the diet. Average daily gain was 1.46, 1.56, 1.58, and 1.61 kg for heifers fed 0, 2, 4, and 6% flax, respectively (linear, P = 0.03). Final BW in Exp. 1 after the finishing period was increased (linear, P = 0.04) with increasing inclusion of flax in the receiving diets. In Exp. 2, growth performance and mortality during the receiving period were not different among treatments (P > 0.12). During the receiving period in Exp. 2, incidence of 1st respiratory treatment tended to be greatest (P = 0.09) for heifers fed 4% flax. During the finishing period, DMI were 8.4, 8.4, 8.0, and 8.1 kg/d for 0, 2, 4, and 6% flax, respectively (linear, P = 0.05). In Exp. 2, LM areas were greatest (quadratic, P = 0.04) for cattle fed 2% flax at receiving. In general, feeding flax during the receiving period may have the potential to improve growth performance; however, performance between experiments was variable, and many factors excluding flax feeding may have contributed to this response.

M. J. Quinn, E. S. Moore, D. U. Thomson, B. E. Depenbusch, M. L. May, J. J. Higgins, J. F. Carter and J. S. Drouillard. The effects of feeding flaxseed during the receiving period on morbidity, mortality, performance, and carcass characteristics of heifers.
Published online first on June 20, 2008 J. Anim Sci. 1910. doi:10.2527/jas.2007-0271





Weaning & source impact on performance and BRD

The study objective was to determine health and performance of ranch calves from different pre-conditioning strategies during a 42-d receiving period when commingled with calves of unknown health histories from multiple sources. Steer calves from a single source ranch (RANCH) were weaned and immediately shipped to a feedlot (WEAN, initial BW = 247 ± 29 kg); weaned on the ranch for 45 d before shipping, but did not receive any vaccinations (WEAN45, initial BW = 231 ± 26 kg); or weaned, vaccinated with modified live viral vaccine, and held on the ranch for 45 d before shipping (WEANVAC45, initial BW = 274 ± 21 kg). Multiple-source steers were purchased through auction markets (MARKET, initial BW = 238 ± 13 kg), and upon receiving, a portion of ranch-origin steers from each weaning group were commingled with a portion of MARKET cattle (COMM). The experimental design was completely randomized with a 2 x 3 +1 factorial arrangement of treatments. Factors were RANCH vs. COMM and weaning management (WEAN vs. WEAN45 vs. WEANVAC45) as the factors; MARKET cattle served as the control. Calves of WEAN, WEAN45, and MARKET were vaccinated on arrival at the feedlot. Ranch-origin calves tended (P = 0.06) to have greater ADG than COMM or MARKET calves, although ADG was not affected (P = 0.46) by weaning management. Across the 42-d receiving period, DMI was not affected (P = 0.85) by cattle origin. However, MARKET, WEAN45, and WEANVAC45 calves consumed more (P < 0.001) DM than WEAN calves. Gain efficiency was not affected (P > 0.11) by treatment. Ranch-origin calves were less (P < 0.001) likely to be treated for bovine respiratory disease than MARKET calves; COMM calves were intermediate. Calves that were retained on the ranch after weaning (WEAN45 and WEANVAC45) were also less likely to be treated (P = 0.001) than MARKET or WEAN calves. As expected, differences in morbidity related to differences in health costs. Calves of WEAN45 and WEANVAC45 had lower (P < 0.001) health costs than MARKET and WEAN calves. On arrival, serum haptoglobin concentrations were greater (P < 0.001) in MARKET and WEAN compared with WEAN45 and WEANVAC45 calves. Calves from a single source that are retained on the ranch for 45 d after weaning exhibit less morbidity and lower health costs during the receiving period at the feedyard than when cattle are commingled or trucked to the feedyard immediately after weaning.

Step, D.L., C. R. Krehbiel, H. A. DePra, J. J. Cranston, R. W. Fulton, J. G. Kirkpatrick, D. R. Gill, M. E. Payton, M. A. Montelongo and A. W. Confer. Effects of commingling beef calves from different sources and weaning protocols during a 42-day receiving period on performance and bovine respiratory disease Published online first on June 20, 2008 J. Anim Sci. 1910. doi:10.2527/jas.2008-0883




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