Informationen aus der EWG [EG] (V)

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Body condition score at parturition and postpartum supplemental fat effects on cow and calf performance

Three-year-old Angus x Gelbvieh beef cows nutritionally managed to achieve a BCS of 4 +/- 0.07 (479.3 +/- 36.3 kg of BW) or 6 +/- 0.07 (579.6 +/- 53.1 kg of BW) at parturition were used in a 2-yr experiment (n = 36/yr) to determine the effects of prepartum energy balance and postpartum lipid supplementation on cow and calf performance. Beginning 3 d postpartum, cows within each BCS were assigned randomly to be fed hay and a low-fat control supplement or supplements with either high-linoleate cracked safflower seeds or high-oleate cracked safflower seeds until d 60 of lactation. Diets were formulated to be isonitrogenous and isocaloric, and safflower seed supplements were provided to achieve 5% of DMI as fat. Ultrasonic 12th rib fat and LM area were lower (P < 0.001) for cows in BCS 4 compared with BCS 6 cows throughout the study. Cows in BCS 4 at parturition maintained (P = 0.02) condition over the course of the study, whereas cows in BCS 6 lost condition. No differences (P = 0.44 to 0.71) were detected for milk yield, milk energy, milk fat percentage, or milk lactose percentage because of BCS; however, milk protein percentage was less (P = 0.03) for BCS 4 cows. First-service conception rates did not differ (P = 0.22) because of BCS at parturition, but overall pregnancy rate was greater (P = 0.02) in BCS 6 cows. No differences (P = 0.48 to 0.83) were detected in calf birth weight or ADG because of BCS at parturition. Dietary lipid supplementation did not influence (P = 0.23 to 0.96) cow BW change, BCS change, 12th rib fat, LM area, milk yield, milk energy, milk fat percentage, milk lactose percentage, first service conception, overall pregnancy rates, or calf performance. Although cows in BCS of 4 at parturition seemed capable of maintaining BCS during lactation, the overall decrease in pregnancy rate indicates cows should be managed to achieve a BCS >4 before parturition to improve reproductive success.     

A framework for understanding the potential for emerging diseases in aquaculture

Numerous diseases have emerged as serious economic or ecological problems in aquaculture species. The combination of factors behind the emergence of each disease is unique, but various common factors are apparent. We combine risk-analysis methods and virulence theory with historical examples (mainly from salmonid production) to identify key disease-emergence risk factors. Diseases have emerged through pathogen exchange with wild populations, evolution from non-pathogenic micro-organisms and anthropogenic transfer of stocks. Aquacultural practices frequently result in high population densities and other stresses (such as intercurrent disease) which increase the risk of infection establishment and spread. As aquaculture expands and new species are farmed, diseases will continue to emerge and affect both wild and farmed fish adversely. The rate and extent of emergence can be reduced by the application of biosecurity programmes designed to mitigate the risk factors for disease emergence.     

Multifunctional carbon nanotube yarns by downsizing an ancient technology

By introducing twist during spinning of multiwalled carbon nanotubes from nanotube forests to make multi-ply, torque-stabilized yarns, we achieve yarn strengths greater than 460 megapascals. These yarns deform hysteretically over large strain ranges, reversibly providing up to 48% energy damping, and are nearly as tough as fibers used for bulletproof vests. Unlike ordinary fibers and yarns, these nanotube yarns are not degraded in strength by overhand knotting. They also retain their strength and flexibility after heating in air at 450 degrees C for an hour or when immersed in liquid nitrogen. High creep resistance and high electrical conductivity are observed and are retained after polymer infiltration, which substantially increases yarn strength.     

Production and immunological responses associated with controlled-release-capsule vs 5-drench preventive anthelmintic programmes for parasite control in lambs

AIMS: To determine whether: a) using a controlled-release anthelmintic capsule (CRC) instead of a programme of 5 oral drenches administered at 3-4 week intervals, would delay the development of anti-parasite immunity in lambs; b) the use of ivermectin instead of albendazole, administered either as a CRC or as a programme of 5 oral drenches, would delay the development of anti-parasite immunity in lambs; c) lambs treated with CRCs would have higher liveweight gains than lambs drenched orally 5 times at 3-4 week intervals, and; d) delayed onset of anti-parasite immunity is associated with reduced liveweight gains in the period following anthelmintic treatment. METHODS: Three field trials were conducted, 1 on a research farm and 2 on commercial sheep farms, in which groups of 30 lambs were treated with either a CRC containing albendazole, a CRC containing ivermectin, 5 oral drenches with albendazole, or 5 oral drenches with ivermectin, administered at 3-4 week intervals. Liveweights and faecal nematode egg counts (FECs) were recorded in all trials. Immunoglobulin-G (IgG) antibody levels to Ostertagia circumcincta and Trichostrongylus colubriformis adult and larval antigens were measured in Trials 1 and 3, and fleece weights and resistance of animals to nematode challenge infection were measured in Trial 1. RESULTS: CRC-treated lambs had higher levels of antibodies to O. circumcincta infective-stage larvae (L3) than orally drenched lambs in Trial 3, but no other immunological differences due to mechanism of delivery were detected. Antibody levels were lower in lambs treated with ivermectin than albendazole, as a CRC or oral drench in Trial 1, but this was not associated with any measurable effects on FEC or productivity. No significant differences (p>0.05) were detected between drench types (albendazole vs ivermectin) or delivery mechanisms (CRC vs oral drenching) in any of the production parameters measured, in any of the trials. Albendazole-CRCs failed to control FECs in all 3 trials. CONCLUSIONS: Although some differences between treatments in antibody levels were detected these were not associated with measurable differences in level of parasitism or productivity of lambs. CRC use did not appear to offer substantial gains in productivity over a structured programme of 5 oral drenches administered at 3-4 week intervals.     

Darwinian medicine: applications of evolutionary biology for veterinarians

Every medical phenomenon has both a mechanistic explanation and an evolutionary explanation. Veterinarians are accustomed to dealing with the mechanistic, the "what" or the "how", of various disease conditions, and applying treatment accordingly. Darwinian medicine is a field that addresses the evolutionary explanation, the "why" for various medical conditions. This review focuses on these Darwinian explanations and is divided into 4 main categories--host defenses, virulence, genetic conflict, and incomplete adaptation to a changing environment. Each of these areas is reviewed, with examples of evolutionary reasons for disease conditions. Consideration of adaptationist reasons for many of these disease phenomena should make veterinarians better clinicians, educators, and researchers.