A pilot study on the foraging behaviour of heifers in intensive silvopastoral and monoculture systems in the tropics.

Intensive silvopastoral systems (ISS) are a sustainable alternative to monoculture systems (MS). The presence of trees and legumes improves animal welfare due to the increased food quality and quantity and the presence of shade while providing a variety of environmental services. As cattle behaviour is greatly affected by environmental conditions, knowledge on the behavioural trade-offs that cattle make to meet their demands while foraging in different grazing systems is important, as this will help us understand the perceived advantages of ISS. This pilot study assessed the behaviour of heifers in an ISS (n=8 heifers) and MS (n=8 heifers) in the Mexican tropics during the dry and rainy seasons, and its relationship with forage availability, mean travelled distance and the temperature humidity index (THI). In both seasons, daily foraging times were longer in the MS than the ISS (P<0.01). The duration of rumination was higher for ISS (P<0.01) and the duration of lying was higher for the dry season (P<0.05). The decrease in foraging times in relation to THI was significantly higher in the ISS than in the MS (mean slope±SE: ISS=-4.64±0.34; MS=-2.34±0.22; t=-14.20, P<0.001). The results suggest that the forage availability and access to shade in the ISS allow cattle to rest longer and increase rumination, whereas cattle in MS spend more time searching for food and foraging at times of the day were the temperatures were higher as a compensatory strategy, which potentially decreases cattle's welfare and production qualities when compared with the ISS. In conclusion, ISS are likely to generate positive behavioural trade-offs that result in better welfare conditions and higher productive potential.

Social behaviour of cattle in tropical silvopastoral and monoculture systems.

Silvopastoral systems can be a good alternative for sustainable livestock production because they can provide ecosystem services and improve animal welfare. Most farm animals live in groups and the social organization and interactions between individuals have an impact on their welfare. Therefore, the objective of this study was to describe and compare the social behaviour of cattle (Bos indicus×Bos taurus) in a silvopastoral system based on a high density of leucaena (Leucaena leucocephala) combined with guinea grass (Megathyrsus maximus), star grass (Cynodon nlemfuensis) and some trees; with a monoculture system with C. nlemfuensis, in the region of Merida, Yucatán. Eight heifers in each system were observed from 0730 to 1530 h each day for 12 consecutive days during the dry season and 12 consecutive days during the rainy season. The animals followed a rotation between three paddocks, remaining 4 days in each paddock. The vegetation was characterized in the paddocks of the silvopastoral system to estimate the average percentage of shade provided. To make a comparison between systems, we used a t test with group dispersion, and Mann-Whitney tests with the frequency of affiliative and agonistic behaviours. We assessed differences in linearity and stability of dominance hierarchies using Landau's index and Dietz R-test, respectively. The distance of cows with respect to the centroid of the group was shorter, and non-agonistic behaviours were 62% more frequent in the intensive silvopastoral system than in the monoculture one. Heifers in the silvopastoral system had a more linear and non-random dominance hierarchy in both seasons (dry season: h'=0.964; rainy season: h'=0.988), than heifers in the monoculture system (dry season: h'=0.571, rainy season: h'=0.536). The dominance hierarchy in the silvopastoral system was more stable between seasons (R-test=0.779) than in the monoculture system (R-test=0.224). Our results provide the first evidence that heifers in the silvopastoral system maintain more stable social hierarchies and express more sociopositive behaviours, suggesting that animal welfare was enhanced.

Funcionalismo hepático en ratas wistar tratadas con dosis terapéuticas de nimesulide / Liver function in wistar rats treated with therapeutic doses of nimesulide

Introducción: El nimesulide es un analgésico antiinflamatorio no esteroideo, asociado en reportes de casos clínicos con hepatotoxicidad. Sin embargo, se han publicado pocos estudios controlados en animales. Objetivo: Determinar si la administración de dosis terapéuticas de nimesulide, durante diferentes periodos, altera el funcionalismo hepático en ratas Wistar machos y hembras. Materiales y métodos: Cuarenta ratas Wistar fueron distribuidas en 4 grupos de 10 cada uno (5 hembras y 5 machos). Grupo I (control): recibió 0.1 mL de solución salina durante 7 días, los animales de los grupos II, III y IV fueron tratados con nimesulide (3 mg/kg) durante 7, 21 y 35 días, respectivamente. Se determinaron niveles séricos de bilirrubina, fosfatasa alcalina y transaminasas. Resultados: La actividad de la enzima alanino-amino-transferasa (ALT) aumentó en machos (p< 0.01) y hembras (p < 0.02) de los grupos III y IV respecto a los controles. En los machos de los grupos II y IV aumentó la fosfatasa alcalina en comparación con las hembras de los mismos grupos (p < 0.05). Las bilirrubinas di - recta y total disminuyeron en las hembras del grupo IV respecto al control (p < 0.03). Conclusiones: Los resultados sugieren que a dosis terapéuticas el nimesulide altera el funcionalismo hepático en ratas Wistar.

Introduction: Nimesulide is a non-steroidal antiinfflamatory drug associated with hepatotoxicity. Nevertheless, there have few published controlled studies with animals. Objec - tive: Determine whether the administration of therapeutic doses of nimesulide during differents periods alters hepatic function in male and female rats. Materials and me - thods: Forty Wistar rats were classified into 4 groups of 10 rats each. Group I received 0,1 ml of saline for 7 days, whe reas the animals from groups II, III and IV were treated with Ni mesulide (3 mg/kg) during 7, 21 and 35 days, respectively. It has determined serum levels of bilirubin, alkaline phos pha tase and transaminases. Results: Alanino-amino-transferase (ALT) enzyme was increased in males (p<0.01) and females (p<0.02) from groups III and IV in com parison with the control group. Alkalin phosphate increased in males from groups II and IV in comparison with the females from these same groups (p< 0.05). Direct and total bilirubins decreased in group IV females (p< 0.03) in comparison with the control group. Conclusions: The administration of therapeutic doses of nimesulide affects hepatic function on Wistar rats.

Prevalence of BRCA1 and BRCA2 gene mutations in families with medium and high risk of breast and ovarian cancer in Brazil

Of all malignant neoplasias affecting women, breast cancer has the highest incidence rate in Brazil. The objective of the present study was to determine the frequency of genetic modifications in families with medium and high risk for breast and ovarian cancer from different regions of Brazil. An exploratory, descriptive study was carried out on the prevalence of the BRCA1 and BRCA2 mutations in case series of high-risk families for breast and/or ovarian cancer. After heredogram construction, a blood sample was taken and DNA extraction was performed in all index cases. The protein truncation test was used to screen for truncated mutations in exon 11 of the BRCA1 gene and in exons 10 and 11 of the BRCA2 gene. Of the 612 individuals submitted to genetic testing, 21 (3.4 percent), 19 women and 2 men, had mutations in the BRCA1 or BRCA2 genes. Of the 19 BRCA1 mutations found in the 18 participants, 7 consisted of ins6kb mutations, 4 were 5382insC, 3 were 2156delGinsCC, 2 were 185delAG, 1 was C1201G, 1 was C3522T, and 1 was 3450del4. With respect to the BRCA2 gene, 3 mutations were found: 5878del10, 5036delA and 4232insA (one case each). The prevalence of germline mutations in the BRCA1 and BRCA2 genes found in the present study was lower than reported by other studies on high-risk Brazilian populations. The inclusion of individuals with medium risk may have contributed to the lower prevalence observed.

Prevalence of BRCA1 and BRCA2 gene mutations in families with medium and high risk of breast and ovarian cancer in Brazil.

Of all malignant neoplasias affecting women, breast cancer has the highest incidence rate in Brazil. The objective of the present study was to determine the frequency of genetic modifications in families with medium and high risk for breast and ovarian cancer from different regions of Brazil. An exploratory, descriptive study was carried out on the prevalence of the BRCA1 and BRCA2 mutations in case series of high-risk families for breast and/or ovarian cancer. After heredogram construction, a blood sample was taken and DNA extraction was performed in all index cases. The protein truncation test was used to screen for truncated mutations in exon 11 of the BRCA1 gene and in exons 10 and 11 of the BRCA2 gene. Of the 612 individuals submitted to genetic testing, 21 (3.4%), 19 women and 2 men, had mutations in the BRCA1 or BRCA2 genes. Of the 19 BRCA1 mutations found in the 18 participants, 7 consisted of ins6kb mutations, 4 were 5382insC, 3 were 2156delGinsCC, 2 were 185delAG, 1 was C1201G, 1 was C3522T, and 1 was 3450del4. With respect to the BRCA2 gene, 3 mutations were found: 5878del10, 5036delA and 4232insA (one case each). The prevalence of germline mutations in the BRCA1 and BRCA2 genes found in the present study was lower than reported by other studies on high-risk Brazilian populations. The inclusion of individuals with medium risk may have contributed to the lower prevalence observed.