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Our goal was to define a breeding objective for Brangus beef cattle in Brazil. Bioeconomic models were produced and used to estimate economic values (EVs). The scenarios simulated were typical full-cycle beef production systems that are used in tropical and subtropical regions. The breeding objective contained pregnancy rate (PR), warm carcass weight (WCW), mature cow weight (MCW), number of nematode eggs per gram of faeces (EPG) and tick count (TICK). Two models were used in series to estimate the EV. A deterministic model was used to simulate effects of PR, WCW and MCW on profitability with a constant parasite load. Subsequently, stochastic models were used to estimate economic values for TICK and EPG as consequences of their environmental effects on weight gains, mortality and health costs. The EV of PR, WCW, MCW, EPG and TICK, was US$1.59, US$2.11, −US$0.24, −US$5.35 and −US$20.88, respectively. Results indicate positive emphasis should be placed on PR (12.49%) and WCW (65.07%) with negative emphasis on MCW (13.92%), EPG (2.77%) and TICK (5.75%). In comparison with the indexes usually used, these results suggest a reformulation in the selection indexes of the beef production system in tropical and subtropical regions in order to obtain greater profitability.  相似文献   
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The effect of rider weight on equine welfare and performance requires further investigation. The objective of this prospective, cross-over, randomised trial was to assess gait and behavioural responses of horses to riders of similar ability, but different bodyweights. Six nonlame horses in regular work were ridden by each of four riders: Light (L), Moderate (M), Heavy (H) and Very Heavy (VH). Saddle fit was assessed subjectively throughout the study. Each horse was ridden twice by riders L and M, and once by rider H. Rider VH rode five horses once and one twice. Each horse-rider combination undertook a standardised, 30-min ‘dressage-test' which was abandoned if we observed lameness grade ≥ 3/8 in one limb, grade ≥ 2/8 in ≥ 2 limbs, or ≥ 10/24 behavioural markers of pain. Horses were reassessed in hand 45–60 min after any abandonment. Mean rider bodyweights, body mass index (BMI) values and rider:horse bodyweight percentages for the L, M, H and VH riders were respectively: 60.8, 77.8, 91.0, 142.1 kg; 23.2, 28.0, 26.3, 46.9 kg/m2; 10.0–11.7%, 12.8–15.0%, 15.3–17.9%, 23.6–27.5%. All 13 H and VH rider tests (lameness, n = 12; behaviour, n = 1) and one of 12 M rider tests (lameness) were abandoned. Lameness was confirmed using inertial measurement unit data. All horses trotted sound after test abandonment and completed the study moving well when ridden. Limitations of the study were saddle fit was not ideal in all horse-rider combinations and abandonment criteria were subjective. The conclusions and clinical relevance of the study were that large riders can induce temporary lameness and behaviours consistent with musculoskeletal pain. This may relate to rider bodyweight and/or weight distribution. Riders M and H had similar BMI but markedly different test abandonment rates, therefore bodyweight is likely to be more relevant than BMI. Further work is required to determine if horse fitness, adaptation to heavier weights and better saddle fit for heavier/taller riders will increase horses' weight-carrying capacity.  相似文献   
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This study aimed to investigate the effects of chitosan and whole raw soybean on nutrient intake, apparent digestibility, nitrogen utilization, microbial protein synthesis, blood metabolites, feeding behavior, ruminal fermentation, digesta kinetics, and reticular flow of nutrients of buffaloes. Four ruminally‐cannulated Murrah buffaloes (351 ± 15 kg of initial BW) were randomly assigned according to a 4 × 4 Latin square design. Treatments were arranged as 2 × 2 factorial arrangement: the first factor was whole raw soybean (WRS), and the second factor was chitosan (CHI) with or without their inclusion in diets. Intake and apparent digestibility of ether extract (p < .01; p = .04, respectively), non‐fiber carbohydrates intake (p = .03) and apparent ruminal digestibility of dry matter (p = .01) were affected by diets. An interaction effect or tendency was observed for microbial nitrogen (p = .09), concentrations, ruminal ammonia nitrogen (p = .05), total volatile fatty acid (p = .03). Association of chitosan with whole raw soybean has potential effects as a modulator of rumen fermentation; therefore, chitosan can be applied as an alternative non‐ionophore for Murrah buffaloes.  相似文献   
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Poultry by‐product meal (PBM) is a popular animal‐based protein source tested in aquaculture feed formulations for replacing fishmeal (FM), mainly due to its high protein content, relatively cheap price and broad availability. However, due to the well‐documented variability in success of PBM inclusions, a meta‐analysis approach was utilized to summarize the efficacy and success of PBM inclusion in aquaculture diet formulations substituting FM. Hedges’g effect sizes were calculated by quantitatively comparing final weight and feed conversion ratio (FCR) between animals fed control (100% FM) and PBM‐supplemented FM diets using data from 47 published articles targeting 33 different species (141 and 96 effect size calculations for final weight and FCR, respectively). In addition, several analyses were performed to determine the effect of different moderators as well as variation across species. Meta‐regression was conducted to evaluate the effect of varying PBM proportions of the diet on the response variables. Overall, a non‐significant final weight but a significant higher FCR was detected with aquaculture species fed PBM diets. Similar trends in final weight were observed for subgroups. However, FCR for crustaceans and marine fish fed PBM diets was not significantly different than those fed control diets. In both freshwater and marine fish, ‘species’ was a significant moderator effect on responses, while the ‘level of FM replacement’ was significant only in marine fish. Higher between‐study heterogeneity was detected for fish, which may be due to the influence of certain factors, such as variability in nutritional quality and palatability and digestibility of PBM or due to variability on the fish meal used. In contrast, low between‐study variation was observed in crustaceans indicating consistent success in PBM‐supplemented diets for shrimp compared with fish.  相似文献   
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