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ABSTRACT This study aimed to evaluate the effect of the inclusion of spineless cactus (Opuntia stricta Haw) in the diet of sheep on the balance of macrominerals, renal function, and blood metabolites. Five sheep cannulated in the rumen (61.5±9.5kg body weight) were used in a 5 × 5 Latin square composed of five diets and five experimental periods. The experimental period lasted 105 days, with five periods of 21 days each. Four diets containing levels of spineless cactus (121, 245, 371, and 500g/kg of dry matter (DM)), and a control diet were evaluated. Samples of the ingredients, orts, feces, urine, and blood were collected. Spineless cactus inclusion in sheep diets increased the DM intake, ash, oxalate, and all macrominerals intake (P < 0.05), but did not affect the urinary and fecal excretion of P, as well as the concentration of P in the blood (P > 0.05). It is possible to verify that the inclusion of spineless cactus, up to the level of 500g/kg of DM in the sheep diets, does not appear to cause damage to the animal’s health. Its inclusion does not compromise kidney function or blood metabolites evaluated herein.

ABSTRACT The objective was to evaluate the effect of water salinity and environmental temperature on the nutrient consumption, digestibility, nitrogen balance, and mineral excretion of creole goats. Thirty-six males with an average age of 5.0±0.6 months and an average weight of 20.0±2.3kg were housed in metabolic cages. They are distributed in a completely randomized design, with a 2×3 type crossover (2 temperatures (T1 = 26±0.6ºC and T2 = 32±1.2ºC) and three levels of salinity (1.0, 6.0, and 12.0 dS m-1). The temperature influenced (P0.05) of temperatures or water salinity levels; the animals consumed and retained averages of 10.31 and 4.19 g day-1 of nitrogen in the body, respectively. The different water salinity levels influenced (P

The objective of the present study was to evaluate the substitution of soybean meals by biodiesel co-products on the performance and nutrient balance of lactating cows on pasture. Twelve dairy cows (7/8 Holstein-Gir) in early lactation were included in this feeding trial. These animals had an average daily milk yield of 21.1 kg and were distributed in a 4 × 4 triple Latin square experimental design. Protein supplements fed to these lactating cows contained peanut meal, cotton and sunflower as a complete replacement for soybean meal. Nutrient intake and digestibility, milk production, microbial protein synthesis, energy and protein balance were the parameters assessed in this study. Supplements containing different biodiesel co-products did not influence (P > 0.05) the level of forage intake, supplementation and nutrient by lactating cows, except for the total digestible nutrients (TDN) intake which was higher (P ≤ 0.05) in cows supplemented with cottonseed meal. The cotton meal also promoted higher digestibility of TDN (P = 0.001) and total carbohydrates (TCHO; P = 0.001) of the diet and, as a result, higher energy consumption (P = 0.01) and lower negative energy balance (P = 0.01). Cottonseed meal is a co-product of the biodiesel industry that has the ability to replace soybean meal as a source of protein in the supplement without affecting performance and promoting greater energy availability, demonstrating its ability to reduce the effects of negative energy balance in cows at the beginning of lactation kept on tropical pastures., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Santos, Saraiva, Gonzaga Neto, Maia, Lees, Sejian, Maia, Medeiros and Fonsêca.)

This research was carried out to evaluate the effect of replacing dietary soybean meal with peanut meal, on intake and digestibility, microbial protein synthesis, and nitrogen balance in lactating cows. Twelve crossbred Holstein × Gyr cows at 84 days in milk (DIM) were distributed in a triple 4 × 4 Latin square. The treatments consisted of increasing peanut meal levels (0, 330, 670, and 1000 g/kg dry matter basis) in replacement of soybean meal in the diet. Replacing soybean meal with peanut meal had no effect on the intake and digestibility of dry matter and nutrients. Nitrogen balance and percentage of retained were similar among treatments. Microbial nitrogen synthesis and microbial protein synthesis efficiency were similar among treatments. Thus, in regions where its cost is lower, peanut meal can totally replace soybean meal in dairy cow diets without affecting nitrogen balance and microbial protein synthesis., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

The objective of this study was to evaluate the effects of replacing soybean meal with peanut meal on milk production, chemical and fatty acid composition, nutritional quality indicators of the lipid fraction, and the economic viability of the diets. Twelve crossbred cows in the initial lactation third, with a bodyweight of 545 ± 37 kg and average milk production of 28 kg/day of milk were distributed in a 4 × 4, triple Latin square design. The treatments consisted of diets with substitution levels of soybean meal for peanut meal (0; 330; 670; and 1000 g/kg in DM). The peanut meal inclusion to replace soybean meal in the diets provided a decreasing linear effect for the protein (P = 0.02) and casein (P = 0.01) concentration in milk. Milk production, total solids concentration, feed efficiency, fatty acid composition, and nutritional quality indicators of the milk lipid fraction were not influenced by the substitution levels. The diet cost per kg DM decreased due to the peanut meal inclusion as a protein source. The partial or total substitution of soybean meal for peanut meal in the feedlot cows diet reduces the cost of feed, without affecting milk production and total solids yield., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Oilseed cakes can partially replace corn or soy used in the diet without losing animal performance. The objective was to carry out a meta-analysis and principal component analysis to evaluate the effects of cakes on the intake and apparent digestibility coefficient (ADC) of dry matter (DM) and milk production and composition in lactating dairy cows. The data set used in the meta-analysis came from 51 studies published between 2009 and 2019, which resulted in 119 studies with 18 types of cakes evaluated in 1350 cows. Cows fed with cakes increased dry matter intake (DMI) by 0.366 kg d -1 (P < 0.001) and DMI as a function of the animal's body weight by 0.103% (P < 0.0001) compared with the diet without cake. The milk protein content decreased by 0.050% (P < 0.010). The contents of neutral detergent fiber (NDF) (26%-%) and ether extract (EE) (3%-7%) of the cake diets did not affect ADCDM. Cakes with contents between 10% and 30% can replace corn or soy in the diet without affecting milk production, components (fat, protein, and lactose), and contents (fat and lactose), but it can reduce the milk protein content of milk., (© 2022 Japanese Society of Animal Science.)