ABSTRACT Heat stress compromises turkey’s productivity and increase mortality mainly in the final stages of growth. This study evaluated the effect of perches and its interaction with outdoor access on turkey performance in high environment temperature humidity index (THI). Turkeys were reared in 1.75 × 5 m indoor floor pens and were fed with a standard commercial diet, offered ad libitum according to the productive phase. All poults were housed indoors until 62 d of age. A free-range area for a replicate of 8.75 m2, with natural shadow, was available from 07:00 to 19:00 h. Final density was 10.33 ± 0.22 kg/m2. The treatments were a combination of a factorial arrangement (2 × 2) with or without perches and, with or without access to the outdoors. From 10:00 and 19:00 THI was above critical level of comfort (heat stress). In indoors turkeys, feed intake (FI) decreased, and water intake increased, panting was observed, and had a significantly lower final body weight (BW) and FI than turkeys allowed outdoors (p<0.05). Perch availability decreased final BW and FI (p<0.05). Differences in weight of breast meat, wings, or thighs between treatments were negligible. In conclusion turkeys with outdoor access from 62 d of age had better performance.

ABSTRACT This study was conducted to develop predictive equations for carcass characteristics and primal cut weights of native Mexican guajolotes using body measurements (BM). For this study, a total of 36 male guajolotes (Meleagris gallopavogallopavo), aged 6 to 10 months, and mean slaughter body weight (SBW) of 4543.14 ± 656.60 g, were used. The birds were kept under traditional extensive conditions. ThefollowingBMswererecorded24 h before slaughter: thoracicperimeter (TP), body circumference (BC), body length (BL), wing length (WL), keel length (KL), shank length (SL) and shank diameter (SD). After slaughter, hot carcass weight (HCW), cold carcass weight (CCW), hot dressing percentage (HDP), cold dressing percentage (CDP), organs and viscera weight (VIS) and abdominal fat weight (AFW) were recorded. The carcasses were dissected in to five primal cut (breast, thigh, drumstick, back and wing). The SBW and BMs showed moderate to high positive correlations (p<0.01; 0.34≤r<0.97) with carcass characteristics and primal cut weights. In the equations generated to predict HCW, CCW, HDP, CDP, VIS and AFW, the R2 ranged from 0.40 to 0.96, and the predictor variables were SBW, KL, BC, WL and SL. Regarding the equations developed to predict the primal cut weights, R2 ranged from 0.58 to 0.91. In these models, SBW, BC, SD, WL and KL explained most of the observed variation. The prediction equations obtained in the study had moderate to high accuracy; therefore, they can be used by researchers, technicians and poultry producers to obtain information on the carcass composition of native Mexican guajolotes.

Methane (CH4) gas is a by-product of anaerobic fermentation of carbohydrates in the rumen of ruminant species. Agriculture contributes with 47% of anthropogenic emissions of CH4, being the ruminants responsible for 39% of enteric emissions of CH4. This greenhouse gas (GHG) has twenty-five times higher global warming potential than CO2 and represents a loss of up to 12% of the gross energy consumed by ruminants. The aim of this review is to describe the mechanisms of action of condensed tannins contained in foliage of trees and shrubs, and their effect on rumen microbes, as well as their potential for mitigation of CH4 emissions. The findings suggest that condensed tannins reduce protozoa population up to 79% and along with this, rumen methanogens are decreased by up to 33%. Condensed tannins bounded to proteins and polysaccharides of the ration form complexes which reduce digestibility of dry and organic matter and production of metabolic used by methanogens to reduce CO2 to CH4 In vitro studies suggest that condensed tannins may reduce rumen CH4 up to 63% in vitro and up to 58% in vivo. Additionally, incorporation of condensed tannins in the ration of ruminants might increase weight gain by 26%, maybe due to the increase in the flow of protein of low rumen degradability to the small intestine or to the reduction of energy losses as CH4 in the rumen. It is concluded that incorporation of condensed tannins in the ration of ruminants at 3-6% of dry matter concentrations can reduce CH4 emissions as well as to improve weight gain and milk yield of productive animals.

El metano (CH4) es un gas subproducto de la fermentación de los carbohidratos en el rumen. La agricultura contribuye con el 47% de las emisiones antropogénicas de CH4, siendo los rumiantes responsables del 39% de las emisiones de metano entérico. Este gas de efecto invernadero (GEI) tiene un potencial de calentamiento global 25 veces más que el CO2 y representa una pérdida de hasta el 12% de la energía total consumida por los rumiantes. Este trabajo describe los mecanismos de acción de los taninos condensados contenidos en follajes y frutos y su efecto en los microbios del rumen, así como su potencial en la mitigación de las emisiones de CH4. Los hallazgos sugieren que los taninos condensados reducen la población de protozoos hasta 79%, reduciendo además los metanogenos del rumen hasta en 33%. Los taninos condensados se unen a proteínas y polisacáridos formando complejos, reduciendo así la digestibilidad de la metería seca y orgánica y la producción de H2 metabólico, el que es usado por metanogenos para la reducción del CO2 a CH4. Estudios in vitro sugieren que los taninos condensados pueden reducir el CH4 en el rumen hasta 63%, mientras que in vivo se han registrado reducciones hasta 58% en la producción de CH4. Además, la incorporación de taninos condensados en la ración de rumiantes tiene el potencial de aumentar la ganancia de peso en 26%, relacionando esto al aumento en el flujo de proteína de baja degradación ruminal al intestino delgado o la reducción de la energía perdida en forma de CH4 en el rumen. Se concluye que la incorporación de taninos condensados en la ración de los rumiantes en concentración de 3-6% de materia seca puede reducir las emisiones de CH4 así como mejorar la ganancia de peso y producción de leche de los animales productivos.