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Kansas State University


Beef Research News
Brought to you by Kansas State University College of Veterinary Medicine - Farm Animal Section
February 2008





Biosecurity practices in feedyards

Partitioning of energy in pregnant beef cows

Effect of number of feeding places on performance & behavior

Effect of prebreeding weight or progestin exposure on heifers

Self clearance from BVDV infections in Peru dairies

Improving the Veterinary employment selection process

Biosecurity practices in feedyards

A survey was performed to determine the biocontainment, biosecurity, and security practices at beef feedyards in the Central Plains of the United States. Managers of feedyards in Colorado, Kansas, Nebraska, Oklahoma, and Texas that feed beef cattle for finish before slaughter were surveyed. The feedyards had to have an active concentrated animal feeding operation permit with a 1-time capacity of 1,000 cattle. A voluntary survey of feedyard personnel was conducted. Identified feedyard personnel were interviewed and responses regarding facility design, security, employees, disease preparedness, feedstuffs, hospital or treatment systems, sanitation, cattle sources, handling of sick cattle, and disposal of carcasses were collected in a database questionnaire.

The survey was conducted for 106 feedyards with a 1-time capacity that ranged from 1,300 to 125,000 cattle. Feedyards in general did not have high implementation of biocontainment, biosecurity, or security practices. Smaller feedyards were, in general, less likely to use good practices than were larger feedyards. Results of the survey provided standard practices for biocontainment, biosecurity, and security in feedyards located in Central Plains states. Information gained from the survey results can be used by consulting veterinarians and feedyard managers as a basis for discussion and to target training efforts. Feedyards included in this survey may not have implemented more biocontainment, biosecurity, and security practices for several reasons. They may have been unaware of the risks or the appropriate mitigation strategies to decrease risks. Veterinarians should help managers to better understand the routes of transmission for diseases that are most threatening to their operations and to develop optimal plans aimed at preventing disease transmission. In contrast, managers may have understood the risks but perceived that the mitigation strategies were ineffective or uneconomical.

Information about disease risks and mitigation strategies should be combined with cost-benefit analyses by veterinarians and managers to establish best management practices for each feedyard. Action plans developed in consultation with veterinarians to address disease outbreaks would be valuable to managers for use in educating feedyard employees about preventive actions and steps for an effective response. Additional studies will be needed to enable veterinarians and farm managers to better understand the risks and to determine those mitigation strategies that provide the most economic benefits. Veterinarians are pivotal in educating feedyard staff about the dynamic risk of disease introduction and transmission within the feedyard, which characterizes the industry, and identifying best management practices for biocontainment, biosecurity, and security.

Brandt, A., M. Sanderson, B. DeGroot, D. Thomson, L. Hollis. Biocontainment, Biosecurity, and Security Practices in Beef Feedyards. JAVMA. January 15, 2008 Vol. 232, No. 2, pp. 262-269.


Partitioning of energy in pregnant beef cows

The purpose of this study was to determine if the efficiency of energy retention in pregnant cows was dependent on the time during the pregnancy that feed was offered. Our hypothesis was that restricting feed intake during the second trimester of gestation and providing the saved feed during the third trimester was less energetically efficient than providing the feed during the second trimester. Twenty cows (4 breed composite: 1/4 Hereford, 1/4 Angus, 1/4 Red Poll, and 1/4 Pinzgauer) that had produced 1 calf before the study were fed a diet that consisted of (DM basis) 67.3% chopped corn silage, 27.0% alfalfa hay, 5.5% corn, and 0.2% NaCl. When the cows were 87 ± 0.6 d pregnant, the first nutrient balance measurement was conducted. Six subsequent nutrient balance measurements were taken on d 122 ± 0.6, 143 ± 0.6, 171 ± 0.6, 206 ± 0.6, 241 ± 0.6, and 262 ± 0.6 of gestation. Each nutrient balance measurement consisted of a 96-h total collection of feces and urine and a 24-h indirect calorimetry measurement.

Ten cows were fed for moderate BW gain during the entire pregnancy, and 10 cows were feed-restricted in the second trimester and realimented during the third trimester (low-high, L-H). The BW of the cows at parturition (559 ± 14 kg) did not differ between treatments (P = 0.20). There was a general trend for the proportion of ME intake retained to decrease in moderate cows as pregnancy progressed. The proportion of ME intake retained in L-H cows decreased during the first 49 d of feed restriction, but the proportion of ME retained after 77 d of restriction was greater than that retained at 49 d of restriction. During realimentation, there were no time effects for efficiency of ME conversion to retained energy, but efficiency was greater for L-H cows than moderate cows (P < 0.001). The ability of the cow to adapt its energy metabolism during periods of moderate feed restriction and realimentation allows development of management strategies that alter the time interval of the production cycle during which supplemental feed is offered. Total savings in feed offered during the production year are minimal, but management strategies can be developed that shift which feed resources are being used.

Freetly, H.C., J. A. Nienaber and T. Brown-Brandl. Partitioning of energy in pregnant beef cows during nutritionally induced body weight fluctuation. J. Anim Sci. 2008. 86:370-377.


Effect of number of feeding places on performance and behavior

Seventy-two Friesian calves (BW = 102.0 ± 1.8 kg) were bought from a commercial calf farm and distributed to a factorial arrangement of treatments in a complete block design with 3 treatments and 3 blocks of similar fasted BW to study the effect of increasing the number of feeding places per pen on performance, behavior, and welfare indicators during the 4 wk after arrival. Treatments consisted of 1 (T1), 2 (T2), or 4 (T4) concentrate feeding places/pen (8 calves/pen). Concentrate and straw were fed at 0830 in individual feeders, and animals were allowed to consume on an ad libitum basis. Dry matter intake and ADG were recorded weekly, and blood samples were taken on d 0 (before transport), 7, 14, 21, and 28. Time spent in maintenance activities, number of displacements between calves, and the angular dominance value (ADV) were registered at wk 1 and 3 after arrival. Increasing the number of feeding places per pen resulted in a quadratic response of concentrate and total DMI, ADG, and BW during the 28-d period, with T1 showing the lowest values.

Straw intake and the within-pen SD of ADG tended to decrease linearly (P = 0.10) as the number of feeding places per pen increased. During the 4-wk receiving period, and particularly on d 7 after arrival, serum NEFA responded quadratically, with T1 and T2 calves showing the greatest values. With increasing number of concentrate feeders, the average time spent lying increased (P = 0.001), standing time decreased linearly (P = 0.001), and the diurnal feeding pattern changed (concentrate eating time increased but straw eating time decreased during peak feeding times, P < 0.05). The number of displacements from the concentrate feeders responded quadratically (P < 0.001) with increasing number of feeding places per pen, with T4 calves showing the lowest levels of aggression. In T1 calves, increasing ADV resulted in a linear decrease (P = 0.03) of ADG at wk 1 with a quadratic effect at wk 3 (P < 0.01).

In T2 calves, increasing ADV resulted in a linear decrease (P = 0.04) of ADG at wk 1 but a linear increase (P = 0.02) at wk 3. No effect of social rank on ADG was observed in T4 calves (P > 0.20). Increasing social pressure at the concentrate feeders beyond the threshold of 4 heifers per feeder had a negative effect on performance. Within-pen variability in performance increased linearly as a consequence of greater effects of social dominance. Physiological indicators of welfare were not consistently affected by treatments.

González, L.A., A. Ferret, X. Manteca, J. L. Ruíz-de-la-Torre, S. Calsamiglia, M. Devant and A. Bach. Effect of the number of concentrate feeding places per pen on performance, behavior, and welfare indicators of Friesian calves during the first month after arrival at the feedlot. J. Anim Sci. 2008. 86:419-431.


Effect of prebreeding weight or progestin exposure on beef heifers

Two experiments evaluated prebreeding target BW or progestin exposure for heifers developed lighter than traditional recommendations. Experiment 1 evaluated the effects of the system on heifer performance through subsequent calving and rebreeding over 3 yr. Heifers (229 kg) were assigned randomly to be developed to 55% of mature BW (299 kg) before a 45-d breeding season (intensive, INT; n = 119) or 50% of mature BW (272 kg) before a 60-d breeding season (relaxed, RLX; n = 142). Prebreeding and pregnancy diagnosis BW were greater (P 0.006) for INT than RLX heifers. Overall pregnancy rate did not differ (88.4%; P = 0.51), but RLX heifers had later calving dates (7 d; P < 0.001) and lighter calf weaning weights (194 ± 4 vs. 199 ± 4 kg; P < 0.07) compared with INT heifers. Calf birth weight, calving difficulty, second-calf conception rates, and 2-yr-old retention rate did not differ (P > 0.15) between systems.

Cost per pregnant 2-yr-old cow was less for the RLX than the INT heifer development system. Of heifers that failed to become pregnant, a greater proportion (P = 0.07) of heifers in the RLX than in the INT system were prepubertal when the breeding season began. Therefore, a second 2-yr experiment evaluated melengestrol acetate (MGA, 0.5 mg/d) as a means of hastening puberty in heifers developed to 50% of mature BW. Heifers were assigned randomly to the control (n = 103) or MGA (n = 81) treatment for 14 d and were placed with bulls 13 d later for 45 d. Prebreeding and pregnancy diagnosis BW were similar (280 and 380 kg, respectively; P > 0.10) for heifers in the control and MGA treatments. The proportion of heifers pubertal before breeding (74%), pregnancy rate (90%), calving date, calf weaning weight, and second breeding season pregnancy rate (92%) were similar (P > 0.10) between treatments. Developing heifers to 50 or 55% of mature BW resulted in similar overall pregnancy rates, and supplementing the diets of heifers developed to 50% of mature BW with MGA before breeding did not improve reproductive performance.

Martin, J.L., K. W. Creighton, J. A. Musgrave, T. J. Klopfenstein, R. T. Clark, D. C. Adams and R. N. Funston. Effect of prebreeding body weight or progestin exposure before breeding on beef heifer performance through the second breeding season. J. Anim Sci. 2008. 86:451-459.


Self clearance from BVDV infections in Peru dairies

In this cross-sectional study, a stratified two-stage random sampling procedure was employed to select 221 dairy herds for bulk tank milk (BTM) sampling, and a subset of 55 dairy herds for individual blood sampling of a number of young animals (spot test), to predict presence or absence of current BVDV infection, and for data collection. The prediction was based on the high probability of seropositivity in groups of animals where PI animals are present because of the efficient spread of virus from PI animals to the surrounding group. BTM samples were collected in August 2003 (n = 192) and February 2004 (n = 195), and the 55 herds selected for spot testing and data collection were visited in December 2003. All samples were tested for presence of BVDV specific antibodies using a commercial indirect ELISA (SVANOVA Biotech AB, Uppsala, Sweden). The results demonstrated a very high level of exposure to BVDV in the region, and the proportion of herds with high antibody levels in the BTM was above 95% on both occasions. Despite this, almost two thirds of the herds had spot test results indicating absence of current infection, suggesting a high probability of self-clearance.

A logistic regression model with the results from the spot tests as dependent variable was used to investigate possible herd and management factors associated with self-clearance, and suggested that this may occur regardless of herd size. Even though it is well established that the process of identification and elimination of PI animals is required within a systematic BVDV eradication programme, the present study strongly suggests that many herds may be cleared without intervention even in regions with high cattle density and high BVDV prevalence. Consequently, in any BVDV infected population (regardless of the herd-level BVDV seroprevalence), and at any given point of time, a large proportion of the herds will be free from infection due to self-clearance. Self-clearance is therefore a process that works in favour of any effort to control BVDV, which should be taken into account when planning and assessing the cost-effectiveness of a systematic control programme.

Ståhla, K., A. Lindbergb, H. Riverac, C. Ortizd and J. Moreno-Lópeza. Self-clearance from BVDV infections—A frequent finding in dairy herds in an endemically infected region in Peru. Prev Vet Med. Vol 83, Issues 3-4, 2008. P 285-296.


Improving the Veterinary employment selection process

The rural mixed-animal veterinarian is a critical control point for safe, wholesome, affordable food production and security. The population of students entering food-animal practice is decreasing, and future shortages are likely. Veterinary practice owners will continue to struggle to find associates to fill open positions. Identifying and hiring the correct veterinarian for an open position is a challenging proposition for the rural practitioner. Kansas State University hosted a forum to facilitate the hiring process and provide education regarding the mechanism of an effective selection interview.

A unique experiential technique known as "speed interviews" was used to facilitate communication between conference participants and to practice newly acquired skills. A survey of participants revealed similar viewpoints toward most job attributes. Veterinary students and prospective employers expressed realistic expectations of job requirements, salaries, and debt load. Students expressed willingness to work and desire to practice in the types of practices defined by the veterinarians. The symposium provided valuable insight for practitioners and students regarding the recruitment process. Appropriate and accurate representation at the time of job/associate selection is critical for long-term success and employee retention. The goal of the event was to provide a service to both prospective employers and students by offering education regarding the employment selection interview process and placing attendees in an environment rich with people who have complimentary goals.

White, B.J., K.P. Gwinner, D.M. Andrus, J.B. Prince. Unique Educational Methods to improve the veterinary employment selection process for rural mixed-animal practices. Jour Vet Med Educ. 2007 Vol 34, Issue 4, 517-523.


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Brad White
Beef Production Medicine
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