Phenotypic characterisation and production system of the Nordestino horse from a multivariate perspective.

Zootechnical data is a big challenge in the extensive rearing system of Brazilian locally adapted breeds once smallholdings with limited resources and funds rear them. So, information on Brazil's breeding system of locally adapted breeds is still scarce; this situation is more challenging for equine breeds. The present study aimed to describe the local rearing systems and the phenotypic profile of the Nordestino horse breed in Paraíba state and contribute to breed conservation. Data from males (entire and castrated) and females from 50 municipalities in Paraíba state were used. Two hundred sixty-nine animals (111 females, 121 castrated males, and 37 entire males) from 129 breeders were analyzed. A questionnaire consisting of direct and objective questions was applied to understand the breeding system adopted. There was a predominance of the extensive breeding system (85%), which reflects the adaptation of the Nordestino Horse to the region's natural conditions. The lower frequency of use of cultivated pastures may be related to issues of economic viability since the maintenance of cultivated pastures may require additional investments compared to the use of natural pastures. Entire males had a minimum withers height (WH) of 135 cm. Of the 11 morphometric measurements, only five were considered discriminating by the stepwise analysis. The remaining Nordestino horses have morphological characteristics within the breed standard.

Heat tolerance, thermal equilibrium and environmental management strategies for dairy cows living in intertropical regions.

This review makes an attempt to characterize the physical attributes of heat tolerance, thermal equilibrium and thermal stress thresholds for dairy cows living in tropical environments, with a particular emphasis on pasture-based systems. Under such circumstances, the radiant heat load is the principal climatic factor that determines rates of heat and mass exchanges between cows and the environment. This fact may explain why simple mechanistic models based on air temperature and humidity are not adequately predicting thermal stress thresholds for cattle in tropical regions. To overcome this limitation, the Index of Thermal Stress for Cows (ITSC) and Index for the time spent in shade (ITS), which account for various sources of thermal radiation, were proposed to predict autonomous and behavioral thermoregulation of cows. Overall, the evolutionary adaptation of cattle in tropics favored animals that have cutaneous surface with a skin well protected against penetration of ultraviolet solar radiation (UV), covered by a coat surface with high thermal conductivity. For Holstein breed, although predominantly black animals absorb greater levels of short-wave solar radiation, they may present better protection of skin than white ones. However, dark-colored cows in tropical pastures have potential to absorb as much as 640 W m-2 of thermal radiation. This amount of heat load would require close to 1,300 g h -1 of cutaneous evaporative water loss through sweating to prevent increases to body temperature, where cows do not have access to shade. Cows are motivated to reduce time spent grazing and to seek shade when solar irradiance exceeds 550 W m-2, levels that in equatorial latitudes are likely to occur between 08:00 and 16:00h. This information may help producers improve the welfare of cows, as they can determine more comfortable hours for them to graze, for example, by employing nocturnal grazing. Over the daytime, cows should have access to areas with shade and this could include shade provided via solar panels, which has the potential to improve thermal comfort and sustainability of dairy production in tropical areas.

Optimizing the use of spineless cactus in the finishing diet of lambs: physicochemical properties and sensory characteristics of meat.

BACKGROUND: The use of spineless cactus in finishing diets for lambs improves the carcass quality. However, data about its influence on meat traits is very scarce. The effects of spineless cactus inclusion in the finishing diet of lambs at four levels (0, 150, 300 and 450 g kg-1 of dry matter, DM) in replacement of Tifton hay on the physicochemical and sensory properties of meat were studied. RESULTS: The spineless cactus modified the chemical composition increasing the protein (P < 0.001) and the fat (P < 0.01) contents of meat, presenting the greatest values in lambs fed diets with 150 and 300 g kg-1 (DM) replacing levels, respectively. However, the spineless cactus did not influence the growth performance from 23.7 to 37.3 kg of body weight (on average). In addition, colour parameters of the meat were not affected by the inclusion of spineless cactus in the finishing diet of lambs, resulting in mean values of 37.55, 14.96 and 8.49 for lightness, redness and yellowness, respectively. There were no statistical differences among treatments for cooking loss and shear force, with mean values of 34.8% and 14.8 N, respectively. Finally, the sensorial properties were not affected by the inclusion of spineless cactus in the finishing diet of lambs. CONCLUSION: Spineless cactus could be included up to the level of 300 g kg-1 DM in the finishing diets of lambs to increase the fat content of meat without compromising its sensorial properties. However, further studies about the fatty acid composition of meat from lambs fed diets containing spineless cactus are necessary. © 2019 Society of Chemical Industry.

Ruminal and morphometric parameters of the rumen and intestines of sheep fed with increasing levels of spineless cactus (Nopalea cochenillifera Salm-Dyck).

The objective of this study was to evaluate the ruminal parameters (pH, N-NH3, and microbial protein) and morphometry of the rumen and intestine of sheep fed with a diet containing four different levels of the spineless cactus variety, Baiana. The experiment was conducted at the National Semi-Arid Institute in Campina Grande, PB, Brazil. A total of 40 male sheep submitted to the confinement regime were used in a completely randomized design with four treatments (0, 15, 30, and 45% dry matter basis) and ten replicates, with an initial body weight of 23.7 ± 3.08 kg. Experimental diets were composed of ground corn, soybean meal, urea, mineral supplement, limestone, Tifton 85 hay, and spineless cactus of the Baiana variety. The pH, ammonia nitrogen, and microbial protein were evaluated in the ruminal fluid, alongside the morphometric characteristics of the rumen and intestine. While the addition of the spineless cactus did not affect N-NH3, it caused a linear reduction in the ruminal pH following 4 h of feeding, and also increased the microbial protein. In addition, it stimulated a reduction in the height of the papillae and the muscle layer of the rumen, and induced the mucosal height in the intestine to increase. The addition of up to 30% of spineless cactus in the diet of sheep without a defined breed did not alter the N-NH3, pH, and ruminal histology, but it did increase the production of microbial protein and intestinal mucosa.

Detoxified castor meal in substitution of soybean meal in sheep diet: growth performance, carcass characteristics and meat yield.

The aim of this study was to evaluate the intake, digestibility, performance, and carcass characteristics of lambs fed different levels of replacement (0, 15, 30, and 45 % based on dry matter, DM) of soybean meal (SM) by detoxified castor meal (DCM). Twenty-four and 32 intact hair lambs of nondescript breed (21.7 ± 2.6 kg of initial average body weight and approximately 10 months old) were used, respectively, in the intake and digestibility and performance experiments. The diets were composed of buffel grass hay, ground corn grain, and different levels of SM, DCM, and urea, in a roughage-to-concentrate ratio of 40:60. There was no effect of treatments on DM intake. However, crude protein (CP) and neutral detergent fiber (NDF) intakes were higher at 30 and 45 % than at 0 and 15 % of DCM, which in turn showed higher intake of non-fiber carbohydrates (NFC) (P < 0.05). The organic matter, CP, and NDF digestibilities were not affected, but the digestibility of NFC was lower at 30 and 45 % than at 0 % of DCM (P < 0.05). The average daily gain, feed conversion, slaughter and carcass weights, chilling losses, ribeye area, and absolute values and yields of neck, ribs, loin, and leg were not affected. However, the carcass yield was lower at 45 % of DCM and the absolute value of shoulder was lower at 30 and 45 % of DCM (P < 0.05). The replacement of SM by DCM up to 45 % in the feed of lambs did not negatively affect the intake, digestibility, performance, and main carcass features.