Dietary roughage sources affect lactating Holstein x Zebu cows under experimental conditions in Brazil: a meta-analysis

Tropical Animal Health and Production - To reduce costs, lactating cows are often fed a higher proportion of roughage and alternative feeds; however, such protocols may not lead to optimal milk...     

Application of morphometric measures in estimation of body weight and discrimination of Astyanax lacustris and Astyanax fasciatus

The objective of this study was to verify the direct and indirect correlation between morphometric measures, ratios, body weight and yield in two lambari species Astyanax lacustris and Astyanax fasciatus and whether the discriminant analysis is capable of separating and allocating the species. We used 102 lambari yellow tail and 60 lambari red tail. The fish were weighed and submitted to the evaluation of the morphometric measurements. The direct and indirect effects were evaluated by the method of track analysis, considering weight at slaughter, weight of body parts and body yields as dependent variables and measures and morphometric ratios as explanatory variables. Astyanax lacustris presented higher height and body width, carcass yield and trunk, while A. fasciatus presented higher head yield and viscera weight. The discriminant analysis was able to classify 79.5% of the two species. Track analysis demonstrated that the morphometric measurements can be used for estimation of body and body components’ weight in A. lacustris and A. fasciatus. However, regarding the corporal yield; the morphometric measures were insufficient to explain the yield variations of the species.     

Lethal concentration of Cymbopogon citratus (Poaceae) essential oil for Dolops discoidalis and Argulus sp. (Crustacea: Argulidae)

This study investigated the acute toxicity (LC_50-24 hr) effects of the essential oil of Cymbopogon citratus for adult Argulus sp. and Dolops discoidalis, before and during oviposition. In vitro acute toxicity (LC_50-24 hr) was tested using 20, 40, 60, 80, 100, 120, 140 and 160 μg/L of C. citratus essential oil, and two control groups (one with cultivation tank water and one with cultivation tank water + alcohol) were used. Specimens of Argulus sp. and D. discoidalis submitted to acute toxicity were evaluated using histological procedures. The major chemical compounds of C. citratus essential oil were geranial (47.5%), neral (35.6%) and myrcene (6.7%). The LC_50-24 hr for Argulus sp. adults was 67.97 μg/L, while for D. discoidalis it was 59.55 µg/L. In the oviposition of both species of argulids, maximum mortality began with treatments of 140 μg/L, while the LC_50-24 hr for Argulus sp. and D. discoidalis was 83.98 μg/L and 82.48 μg/L, respectively. In both argulid species exposed to C. citratus essential oil, morphological alterations were observed only in the eyes, and they occurred in the ommatidium and rhabdomeres and were dependent on the concentration of C. citratus essential oil and the parasite species.     

Use of ACP‐104 at Different Dilutions for Sperm Cryopreservation of Dourado,Salminus brasiliensis

The dourado, Salminus brasiliensis, is an important fish in South American river basins. The fish‐farming potential and concerns for its conservation in watersheds has stimulated studies with this species. This study compared the effect of different dilutions of two cryoprotectant solutions on the quality of cryopreserved dourado sperm (duration of motility/motility rate) post‐thawing using three different activating solutions. The cryoprotectant solution ACP‐104 was compared with the cryoprotectant solution most commonly used for dourado, which consists of a mixture of dimethyl sulfoxide, glucose, egg yolk, and distilled water. The semen was mixed following dilutions of semen : cryoprotectant solution: 1:3, 1:9, 1:15, 1:21, and 1:27. The cryopreserved samples were activated using distilled water, 0.45% NaCl or 1% NaHCO₃. The results showed differences in thawed semen using the different activating solutions and cryoprotectant solutions. The glucose‐based cryoprotectant not only resulted in sperm motility equal to or better than that produced by ACP‐104, but the quality was not affected by the dilution. However, the sperm quality improved with increasing dilutions for ACP‐104. Under the conditions tested, the standard cryoprotectant solution is recommended for the cryopreservation of dourado semen because it requires a lower solution volume and, therefore, reduced storage space for the same volume of semen.     

Genomic prediction for meat and carcass traits in Nellore cattle using a Markov blanket algorithm

This study was carried out to evaluate the advantage of preselecting SNP markers using Markov blanket algorithm regarding the accuracy of genomic prediction for carcass and meat quality traits in Nellore cattle. This study considered 3675, 3680, 3660 and 524 records of rib eye area (REA), back fat thickness (BF), rump fat (RF), and Warner–Bratzler shear force (WBSF), respectively, from the Nellore Brazil Breeding Program. The animals have been genotyped using low-density SNP panel (30 k), and subsequently imputed for arrays with 777 k SNPs. Four Bayesian specifications of genomic regression models, namely Bayes A, Bayes B, Bayes Cπ and Bayesian Ridge Regression methods were compared in terms of prediction accuracy using a five folds cross-validation. Prediction accuracy for REA, BF and RF was all similar using the Bayesian Alphabet models, ranging from 0.75 to 0.95. For WBSF, the predictive ability was higher using Bayes B (0.47) than other methods (0.39 to 0.42). Although the prediction accuracies using Markov blanket of SNP markers were lower than those using all SNPs, for WBSF the relative gain was lower than 13%. With a subset of informative SNPs markers, identified using Markov blanket, probably, is possible to capture a large proportion of the genetic variance for WBSF. The development of low-density and customized arrays using Markov blanket might be cost-effective to perform a genomic selection for this trait, increasing the number of evaluated animals, improving the management decisions based on genomic information and applying genomic selection on a large scale.     

GROSS AND HISTOPATHOLOGIC CORRELATION OF LOW‐FIELD MAGNETIC RESONANCE IMAGING FINDINGS IN THE STIFLE OF ASYMPTOMATIC HORSES

With the recent introduction of a 0.25T rotating MRI system, clinical evaluation of the equine stifle joint is now possible in the average equine athlete. A recent publication described common abnormalities of horses with stifle lameness detected with a low‐field MRI system; however, postmortem corroboration of the lesions detected was not possible. Therefore, our objective was to compare postmortem findings with low‐field MRI findings in equine cadaver stifle joints. Ten fresh cadaver stifle joints from horses without clinical signs of stifle disease were evaluated using low‐field MRI, gross dissection, and histopathology. In eight stifles, either the lateral or medial cranial meniscotibial ligament had an irregular shape, fiber separation, or moderate abnormal signal intensity (SI) on all sequences. In five stifles, the medial femoral condyle had articular cartilage fibrillation with or without an osteochondral defect over the weight bearing surface of the medial femoral condyle. All stifles had abnormal SI on all sequences within the patellar ligaments that corresponded with adipose tissue infiltrating between the collagen bundles. Other abnormalities identified included articular cartilage fibrillation of the tibial condyles in three stifles, and articular cartilage fibrillation with chondral defects in the patella in three stifles. All abnormalities detected with low‐field MRI were corroborated by gross dissection. Findings from the current study supported the use of low‐field MRI for detection of stifle joint lesions in horses and demonstrated that some stifle joint pathologies may be subclinical in horses.     

Agroforestry diffusion and secondary forest regeneration in the Brazilian Amazon: further findings from the Rondônia Agroforestry Pilot Project (1992–2002)

In July 1992 the Rondônia Agroforestry Pilot Project (RAPP) was launched in two agricultural municipalities (Nova União and Alto Paraiso) in the western Brazilian Amazon State of Rondônia. The purpose of the RAPP was to assess the conditions under which colonist farmers in the western Amazon would integrate agroforestry plantings into their small-scale farming systems and to assess the performance of those plantings over time. An experimental group consisting of 50 small-scale farmers was selected to participate. Plots were designed to accommodate between 3 and 25 different species, each producing one or more commodities with local market potential (hardwood, fruits, nuts, latexes, oils). Farmers planted seedlings typically on a 1-ha plot, located and designed by each farmer with the advice of a professional Brazilian extensionist. During the first phase of the project (1992–1998), the growth performance of the seedlings and changes in household characteristics were monitored on an annual basis. By 2002, 32 (64.0%) of the original 50 agroforest plots were found in place. This paper updates the research findings based on a 2002 follow-up visit to these 32 farms. In addition to growth performance, the authors’ found that 17.95% of the farms in the neighboring control group had planted trees and other agroforest crops between 1992 and 2002, compared to only 5.38% of farms outside the project area, suggesting spontaneous diffusion. The authors also found a potentially synergistic relationship between agroforestry and secondary forest regeneration with the use of satellite image analysis. The experience of the RAPP indicates that colonist farmers in Amazonia can be successful managers of agroforest plots with minimal external inputs over the long-term (10 years).     

Effects of no‐take area size and age of marine protected areas on fisheries yields: a meta‐analytical approach

Marine protected areas (MPAs) are often promoted as tools for biodiversity conservation as well as for fisheries management. Despite increasing evidence of their usefulness, questions remain regarding the optimal design of MPAs, in particular concerning their function as fisheries management tools, for which empirical studies are still lacking. Using 28 data sets from seven MPAs in Southern Europe, we developed a meta‐analytical approach to investigate the effects of protection on adjacent fisheries and asking how these effects are influenced by MPA size and age. Southern European MPAs showed clear effects on the surrounding fisheries, on the ‘catch per unit effort’ (CPUE) of target species, but especially on the CPUE of the marketable catch. These effects depended on the time of protection and on the size of the no‐take area. CPUE of both target species and the marketable catch increased gradually by 2–4% per year over a long time period (at least 30 years). The influence of the size of the no‐take area appeared to be more complex. The catch rates of the entire fishery in and around the MPA were higher when the no‐take areas were smaller. Conversely, catch rates of selected fisheries that were expected to benefit most from protection increased when the no‐take area was larger. Our results emphasize the importance of MPA size on its export functions and suggest that an adequate, often extended, time frame be used for the management and the evaluation of effectiveness of MPAs.