Performance of finishing beef steers in response to anabolic implant and zilpaterol hydrochloride supplementation

Our objectives were to evaluate the dose/payout pattern of trenbolone acetate (TBA) and estradiol-17β (E(2)) implants and feeding of zilpaterol hydrochloride (ZH) on performance and carcass characteristics of finishing beef steers. A randomized complete block design was used with a 3 × 2 factorial arrangement of treatments. British × Continental steers (n = 168; initial BW = 362 kg) were blocked by BW and allotted randomly to 42 pens (7 pens/treatment; 6 pens/block; 4 steers/pen). The main effects of treatment were implant [no implant (NI); Revalor-S (REV-S; 120 mg of TBA + 24 mg of E(2)); and Revalor-XS (REV-X; 200 mg of TBA + 40 mg of E(2))] and ZH (0 or 8.3 mg/kg of DM for 20 d with a 3-d withdrawal before slaughter). Blocks were split into 2 groups, and block groups were fed for either 153 or 174 d. No implant × ZH interactions were noted for cumulative performance data. Overall, shrunk final BW (567, 606, and 624 kg for NI, REV-S, and REV-X, respectively), ADG (1.25, 1.51, and 1.60 kg), and G:F (0.14, 0.16, and 0.17) increased (P < 0.05) as TBA and E(2) dose increased. Implanting increased (P < 0.05) DMI, but DMI did not differ (P > 0.10) between REV-S and REV-X (8.8 for NI vs. 9.4 kg/d for the 2 implants). From d 1 to 112 of the feeding period, implanting increased (P < 0.05) ADG and G:F, but REV-S and REV-X did not differ (P > 0.10). From d 112 to end, ADG increased by 19% (P < 0.05) and G:F was 18% greater (P < 0.05) for REV-X vs. REV-S. Carcass-adjusted final BW (29-kg difference), ADG (0.2-kg/d difference), and G:F (0.02 difference) were increased (P < 0.05) by ZH, but daily DMI was not affected by feeding ZH. Hot carcass weight was increased (P < 0.05) by ZH (19-kg difference) and implant, with REV-X resulting in the greatest response (HCW of 376 for NI vs. 404 and 419 kg for REV-S and REV-X, respectively; P < 0.05). An implant × ZH interaction (P = 0.05) occurred for dressing percent (DP). Without ZH, implanting increased DP, but DP did not differ (P > 0.10) between REV-X and REV-S. With ZH, REV-X increased (1.7%; P < 0.05) DP vs. NI and REV-S. Marbling score, 12th-rib fat, and KPH were not affected (P > 0.10) by implant or ZH. Overall, treatment increased steer performance and HCW in an additive fashion, suggesting different mechanisms of action for ZH and steroidal implants. In addition, a greater dose of TBA + E(2) and extended payout improved steer performance and HCW.     

The efficacy of anticoccidial products against Eimeria spp. in northern bobwhites

To determine whether chemotherapeutic compounds available for use in domestic poultry are effective at controlling coccidiosis in northern bobwhites (Colinus virginianus), we tested 13 chemotherapeutic anticoccidials including amprolium (250 parts per million [ppm]), clopidol (125 ppm), diclazuril (1 ppm and 2 ppm), decoquinate (30 ppm), lasalocid (120 ppm), monensin (90 ppm), narasin/nicarbazin (36/36 ppm), robenidine (33 ppm), roxarsone (50 ppm), sulfadimethoxine/ ormetoprin (125/75 ppm), salinomycin (60 ppm), semduramicin (25 ppm), and zoalene (125 ppm and 150 ppm). Three tests were conducted using two replicates of 10 birds each: Infected, unmedicated controls and medicated birds were challenged with 1 x 10(6) oocysts of a field isolate consisting primarily of Eimeria lettyae. Subsequently, we tested clopidol, lasalocid, salinomycin, diclazuril (1 ppm), and monensin against mixed-species field isolates containing E. lettyae, E. dispersa, E. colini, or all. Weight gain, gross intestinal lesions, severity of diarrhea, and feed conversion ratio (FCR) 6 days postinfection were recorded. Lesion score, as previously reported, was unreliable as a measure of severity of infection in comparison with weight gain, fecal scores, and FCR. Excellent to good efficacy was found in clopidol, decoquinate, diclazuril (1 ppm and 2 ppm), and in lasalocid, narasin and nicarbazin, robenidine, sulfadimethoxine/ormetoprin, and zoalene (150 ppm). Marginal protection was found using monensin, salinomycin, semduramicin, or a roxarsone/semduramicin combination. Amprolium, roxarsone, and zoalene (125 ppm) were ineffective at controlling coccidia. Two of the six isolates tested against diclazuril 1 ppm and clopidol demonstrated a high degree of resistance, but none of the six isolates was resistant to lasalocid. Four of the eight isolates showed mild to moderate, and moderate to high, resistance against monensin and salinomycin, respectively. These findings indicate that several available compounds are effective at controlling coccidiosis in bobwhites.     

Ecologic and symbiotic approaches to animal welfare, animal rights, and human responsibility

Veterinarians confronted with situations involving animal welfare, animal rights, and human responsibility assume practical importance in the relationships of veterinarians with clients and other constituencies. To help resolve these situations, the authors briefly compare economics and ethics and discuss the types of rights. An attempt is made to bring animal welfare and animal rights into the same conceptual framework, using an ecologic approach. This reaches the thesis that the less human beings allow animals the right of self-determination, the more we should exercise responsibility in their care and welfare. Actively exercised human responsibility in all uses of animals is offered as a practical and valid alternative to the extreme of abolitionism. This alternative also is applied in a cautionary way to the role of veterinary medicine in specieism. The veterinary profession is urged to be active in the middle ground of the field of animal rights and to firmly establish its relationships to animal welfare and human responsibility.     

高蛋白菜籽料和传统菜籽料对于断奶仔猪各性能的影响

<正>为探究高蛋白菜籽料和传统菜籽料对于断奶仔猪各性能的影响,伊利诺伊州动物科学教授Hans H. Stein团队将试验分为如下几组:给断奶仔猪饲喂20%和40%的高蛋白菜籽料(标记为CMA和CMB组) 、饲喂含20%传统菜籽料组(标记为CM-CV组),之后检测不同组猪的生产性能、各器官重量、骨骼中磷酸钙的含量以及血液特征,并与饲料中添加传统菜籽     

Designing sustainable agriculture education: Academics’ suggestions for an undergraduate curriculum at a land grant university

Historically, land grant universities and their colleges of agriculture have been discipline driven in both their curricula and research agendas. Critics call for interdisciplinary approaches to undergraduate curriculum. Concomitantly, sustainable agriculture (SA) education is beginning to emerge as a way to address many complex social and environmental problems. University of California at Davis faculty, staff, and students are developing an undergraduate SA major. To inform this process, a web-based Delphi survey of academics working in fields related to SA was conducted. Faculty from colleges and universities across the US were surveyed. Participants suggested that students needed knowledge of natural and social science disciplines relating to the agri-food system. In addition, stakeholders suggested students learn through experiences that link the classroom to field work, engaging a broad range of actors within applied settings. Stakeholders also emphasized the need for interdisciplinary and applied scholarship. Additionally, they proposed a range of teaching and learning approaches, including many practical experiences. Given the diverse suggestions of content knowledge and means of producing knowledge, the survey presented unique challenges and called into question the epistemological and pedagogical norms currently found in land grant colleges of agriculture. This study has implications for land grant universities seeking to develop undergraduate curriculum appropriate to the field of SA. Damian M. Parr is a doctoral student of Agricultural and Environmental Education, in the School of Education at the University of California at Davis. His professional interests include organic farming, sustainable agriculture, experiential and transformational learning, critical pedagogy, and participatory action research. He is currently working on linking on-campus student initiated sustainable farm and food systems projects to curricula at land grant universities Cary J. Trexler is an assistant professor of Agricultural and Environmental Education at the University of California at Davis where he teaches courses in the history of agricultural education, experiential learning, and research methods for practicing teachers. His research focuses on experiential learning, sustainable agriculture education, and needs of teachers and informal educators within the context of the agri-food system Navina R. Khanna is a graduate student pursuing an MS in International Agricultural Development at the University of California at Davis. She is committed to facilitating community dialogue and education about sustainability issues. Her work at the university focuses on the process and goal of sustainability in agricultural education and campus food system sustainability. Her primary professional interests include democratic participatory process in agri-food system sustainability and urban revitalization Bryce T. Battisti is a doctoral student of Agricultural and Environmental Education, in the School of Education at the University of California at Davis. His research interests include the development of alternative models for university education that are founded on student-centered experiential learning. Specifically, he studies models of permaculture education that lead toward accredited degrees and relates these models to sustainable agriculture degree programs     

Warner-Bratzler and slice shear force measurements of 3 beef muscles in response to various aging periods after trenbolone acetate and estradiol implants and zilpaterol hydrochloride supplementation of finishing beef steers

Our objectives were to determine the effects of zilpaterol hydrochloride (ZH) and the release rate of trenbolone acetate and estradiol-17β on the Warner-Bratzler shear force (WBSF) and slice shear force (SSF) of longissimus lumborum (LL) and the WBSF of gluteus medius (GM) and psoas major (PM) in response to various aging periods. British × Continental steers (n = 168) were assigned to treatments in a 3 × 2 factorial. The main effects of treatment were implant (no implant, Revalor-S, Revalor-XS, Intervet/Schering Plough Animal Health, De Soto, KS) and ZH (0 or 8.3 mg/kg of DM for 20 d). Slaughter group was included as a random effect to account for the variation in days on feed (153 or 174 d). Loins (n = 96) were fabricated to obtain strip loin, top sirloin butt, and tenderloin subprimals. Five 2.54-cm steaks were cut from each subprimal and assigned to 1 of 5 aging periods (7, 14, 21, 28, or 35 d postmortem). Feeding ZH increased (P ≤ 0.01) LL WBSF and SSF values at each aging period compared with controls. Implanting increased (P < 0.05) LL WBSF values at 14 and 21 d, but did not affect LL SSF values (P > 0.05). Only Revalor-S increased (P ≤ 0.05) WBSF values at 28 and 35 d compared with no implant or Revalor-XS. The percentage of LL steaks with a WBSF value below 4.6 kg did not differ (P > 0.05) between ZH supplementation or implant strategy at any aging period, and by d 28, more than 99% of LL steaks registered WBSF values below 4.6 kg. Feeding ZH increased (P < 0.05) GM WBSF values only on d 21. Implant had no effect (P > 0.05) on GM WBSF values. The percentage of GM steaks with a WBSF value below 4.6 kg did not differ (P > 0.05) between ZH supplementation or implant strategy at any aging period. Neither ZH nor implant strategy affected PM WBSF values (P > 0.05). All PM WBSF values were below 4.6 kg on d 7. The results of this study indicated that feeding ZH increased WBSF and SSF of LL steaks, regardless of the aging period; however, the percentage of steaks with WBSF below 4.6 kg did not differ because of ZH or implant. Implanting increased LL WBSF values, but not SSF values. These results showed that although differences existed between implanting, as well as ZH supplementation of British × Continental steers, 99% of LL steaks were classified as tender based on WBSF values by extending aging to 28 d postmortem. It should be noted that 21.2% of 7-d, 13.8% of 14-d, and 17.3% of 21-d ZH steaks had WBSF values greater than 4.6 kg, but 0% of nonsupplemented steaks were greater than 4.6 kg at these aging periods. However, because ZH and implants can increase retail yield of valuable subprimals, such as the tenderloin, considerable value could be captured through ZH supplementation with anabolic implants because shear force was not affected in PM steaks.     

Transformative food systems education in a land-grant college of agriculture: the importance of learner-centered inquiries

In this paper we use a critically reflective research approach to analyze our efforts at transformative learning in food systems education in a land grant university. As a team of learners across the educational hierarchy, we apply scholarly tools to the teaching process and learning outcomes of student-centered inquiries in a food systems course. The course, an interdisciplinary, lower division undergraduate course at the University of California, Davis is part of a new undergraduate major in Sustainable Agriculture and Food Systems. We provide an overview of the course’s core elements—labs, exams, assignments, and lectures—as they relate to social constructivist learning theory and student-centered inquiries. Then, through qualitative analysis of students’ reflective essays about their learning experiences in the course, we demonstrate important transformative outcomes of student-centered inquiries: (1) most students confronted the commodity fetish and tried to reconcile tensions between what the food system is and ought to be, and (2) students repositioned themselves, their thinking, and social deliberation in relation to the food system. Students’ reflections point to the power of learning that emerges through their inquiry process, including in the field, and from critical self-reflection. We also highlight the importance of reflective essays in both reinforcing experiential learning and in helping instructors to better understand students’ learning vis-à-vis our teaching.