Nutritional strategies, performance, digestibility, and carcass traits of Santa Ines and Rabo Largo breeds in a tropical climate

The aim of this study was to compare the performance, intake, digestibility, ruminal parameters, carcass traits, and the yield of commercial cuts of Santa Ines (SI) and Rabo Largo (RL) breeds fed diets with high or low roughage-to-concentrate ratio (R:C) under a tropical climate. Twenty lambs from each breed were individually housed in covered pens and fed the experimental diets for 58 days. The diets were formulated to meet the growth requirements of lambs with a roughage-to-concentrate ratio of 70:30 and 30:70. Significant interactions of breed × diet for nutrient intake were observed (P < 0.05), with SI lambs fed low R:C diet showing higher intake of dry matter, organic matter, crude protein, and total carbohydrates compared to RL lambs fed the same diet. SI lambs fed high R:C diet had higher intake of neutral detergent fiber than RL lambs (P < 0.05). SI lambs displayed better average daily gain and feed efficiency, regardless of diet (P < 0.05). Carcass traits and gastrointestinal components were influenced by breed and diet (P < 0.05). SI lambs fed low R:C diet showed higher subcutaneous fat thickness and better carcass finishing compared to RL lambs (P < 0.05). SI breed lambs exhibited better growth performance, carcass traits, and gastrointestinal characteristics, even when fed diets with a high roughage-to-concentrate ratio.

Chemical Properties, Ruminal Fermentation, Gas Production and Digestibility of Silages Composed of Spineless Cactus and Tropical Forage Plants for Sheep Feeding

The aim was to evaluate the chemical composition, carbohydrates, protein fractionation and in vitro gas production of silages composed of spineless cactus and tropical forages and their effect on sheep performance. Treatments consisted of silages: corn silage (CS), spineless cactus silage (SCS), spineless cactus + gliricidia (SCG), spineless cactus + buffel grass silage (SCBG) and spineless cactus + pornunça (SCP). Silos were opened 60 days after ensiling, and analyses were carried out. The digestibility test lasted for 36 days, with eight animals per treatment. A completely randomized design was adopted. Considering carbohydrate fractionation, CS, SCS and SCBG silages had higher total carbohydrate content (p = 0.001). The SCS silage presented a higher A + B1 fraction (p = 0.001). The SCBG and SCG silages showed a higher B2 fraction (p < 0.0001) compared to the CS and SCS silages. The SCBG and SCP silages presented a higher C fraction (p = 0.001). For protein fractionation, the SCP and SCG silages showed higher crude protein contents (p = 0.001). The CS and SCS silages showed a higher A fraction (p = 0.001). The SCBG silage presented a higher B1 + B2 fraction (p = 0.001). The SCG silage showed a higher B3 fraction (p = 0.006) compared to SCBG silage. The SCS and SCP silages showed a higher C fraction (p = 0.001). Exclusive SCS silage showed higher in vitro dry matter digestibility (p = 0.001), dry matter degradability (p = 0.001) and total gas production (p = 0.001). The use of the SCBG, SCP and SCG silages to feed sheep increased the dry matter intake (p < 0.001). Sheep fed the SCG silage showed greater dry matter and crude protein digestibility compared to the sheep fed the CS, SCS and SCP silages (p = 0.002). There was a higher water intake (p < 0.001) with the use of the SCS and SCG silages to feed the sheep. The SCP and SCG silages provided a greater intake (p < 0.001) and excretion (p < 0.001) of nitrogen by the animals. Although there were no differences between the treatments for daily gains, lambs that received the spineless cactus-based silage associated with tropical forages showed higher gains (160-190 g/day) than lambs that received CS silage (130 g/day). Thus, the use of spineless cactus associated with buffelgrass, pornunça and gliricidia to prepare mixed silages (60:40) to feed sheep has potential use to feed sheep, with positive effects on nutrient degradation and increases in dry matter intake. Under experimental conditions, we recommend the exclusive use of spineless cactus silage associated with buffel grass, pornunça and gliricidia in feeding sheep in semi-arid regions, as it provides nutrients, water and greater daily gains compared to corn silage.

Fermentation Profile, Aerobic Stability, and Chemical and Mineral Composition of Cactus Pear Silages with Different Inclusion Levels of Gliricidia Hay

Cactus pear is used in large proportions in diets for small ruminants in semiarid regions. However, its exclusive use is not recommended due to the low fiber and crude protein content and the high water and mineral content, leading to metabolic disorders, low dry matter intake, and weight loss. The use of mixed cactus silage associated with protein and fibrous sources seeks to overcome the deficits in dry matter, fiber and crude protein, aiming to improve the nutritional quality of the diets that will be offered to ruminants. Thus, the use of gliricidia hay in cactus pear silages could represent an important alternative to improve the nutritional and fermentative characteristics of the ensiled material. Therefore, our aim was to evaluate the fermentation dynamics, nutritional characteristics, and aerobic stability of mixed silages of cactus pear combined with different levels of gliricidia hay. This was a completely randomized experimental design with five treatments and five repetitions. The treatments consisted of different levels of inclusion of gliricidia hay (0, 10, 20, 30, and 40% on a dry matter basis) in the composition of mixed cactus pear silages. The inclusion of gliricidia hay in the composition of mixed silages of cactus pear resulted in a quadratic effect for dry matter recovery, pH, NH3-N, buffering capacity, aerobic stability, ether extract, P, K, Na, and Zn (p < 0.05). There was a reduction in density, effluent losses, maximum pH, mineral matter, non-fiber carbohydrates, Ca, Mg, Fe, and Mn (p < 0.05), and an increase in the time to reach maximum pH as well as an upward trend in pH, dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber, and B (p < 0.05). Under experimental conditions, the inclusion of gliricidia hay between 20 and 30% in cactus pear-based silage provided an improvement to the chemical composition and fermentation parameters of the silages.

Nanosilica enhances morphogenic and chemical parameters of Megathyrsus maximus grass under conditions of phosphorus deficiency and excess stress in different soils

Phosphorus (P) imbalances are a recurring issue in cultivated soils with pastures across diverse regions. In addition to P deficiency, the prevalence of excess P in soil has escalated, resulting in damage to pasture yield. In response to this reality, there is a need for well-considered strategies, such as the application of silicon (Si), a known element for alleviating plant stress. However, the influence of Si on the morphogenetic and chemical attributes of forage grasses grown in various soils remains uncertain. Consequently, this study aimed to assess the impact of P deficiency and excess on morphogenetic and chemical parameters, as well as digestibility, in Zuri guinea grass cultivated in Oxisol and Entisol soils. It also sought to determine whether fertigation with nanosilica could mitigate the detrimental effects of these nutritional stresses. Results revealed that P deficiency led to a reduction in tiller numbers and grass protein content, along with an increase in lignin content. Conversely, P excess resulted in higher proportions of dead material and lignin, a reduced mass leaf: stem ratio in plants, and a decrease in dry matter (DM) yield. Fertigation with Si improved tillering and protein content in deficient plants. In the case of P excess, Si reduced tiller mortality and lignin content, increased the mass leaf:stem ratio, and enhanced DM yield. This approach also increased yields in plants with sufficient P levels without affecting grass digestibility. Thus, Si utilization holds promise for enhancing the growth and chemical characteristics of forage grasses under P stress and optimizing yield in well-nourished, adapted plants, promoting more sustainable pasture yields.

Metabolic profile of goats fed diets containing crude glycerin from biodiesel production

Feedlot finishing of goats is a growing practice, but the economic viability of this technology is compromised by the inclusion of ingredients such as corn and soybean. An alternative to minimize this barrier is the use of agroindustry coproducts as substitutes for those ingredients, such as crude glycerol. This study aimed to evaluated the metabolism of crossbred Boer finishing goats fed diets containing crude glycerin from biodiesel production. Thirty-two crossbred, castrated goat of age were distributed in a fully randomized experimental design with four treatments and eight replicates. The experiment lasted 69 days, and goats were fed sorghum silage and concentrate, with the inclusion of crude glycerin in the diet at levels of 0, 50, 100, and 150 g/kg on a dry matter basis. The diets did not have an effect (p > 0.05) on the serum urea levels. Increasing dietary crude glycerin levels did not the influence the metabolic or urinary profiles (p > 0.05). The liver tissue of the goats fed diets containing the highest crude glycerin inclusion levels showed deleterious effects. The inclusion of crude glycerin with approximately 6.6 g/kg methanol caused deleterious effects to the liver tissue of Boer crossbred goats as the glycerin concentrations increased. However, glycerin levels did not cause deleterious effects on the liver tissue or on the serum or urinary profiles. The use of crude glycerin with lower methanol content is recommended for goat diets.

Nanosilica modulates C:N:P stoichiometry attenuating phosphorus toxicity more than deficiency in Megathyrsus maximus cultivated in an Oxisol and Entisol

Silicon (Si) nanoparticles can attenuate nutritional disorders caused by phosphorus in forages through nutritional homeostasis. This paper aims to evaluate the effects of P deficiency and toxicity in Megathyrsus maximus cultivated in two types of soils and to verify whether Si application via fertigation can mitigate these imbalances. The following two experiments were carried out: cultivation of forage plants in pots with Entisol and Oxisol, in a 3 × 2 factorial design, with three nutritional levels of phosphorus (deficient, adequate, and excessive) and two Si concentrations in the irrigation water (0 and 1.5 mmol L-1). Height, number of tillers, rate of leaf senescence, dry matter production, C:N, C:Si, C:P, and N:P ratios; and C, P, and N use efficiencies were evaluated in two growth cycles. P imbalances hampered carbon assimilation, C:N:P homeostasis, and dry matter production. Nanosilica fertigation promoted silicon uptake, improving C:N:P homeostasis and nutritional efficiency in plants under P deficiency and toxicity. Leaf senescence was reduced with addition of Si in plants grown in Oxisol in the three nutritional states of P. Silicon attenuated the stress caused by P toxicity in Entisol and Oxisol, improving production in plants without nutritional stress in Oxisol. The supply of Si nanoparticles in the cultivation of M. maximus can contribute to a more efficient and sustainable use of phosphorus in pastures.

Carcass traits and meat quality of goats fed with cactus pear (Opuntia ficus-indica Mill) silage subjected to an intermittent water supply

The effect of different proportions of cactus pear (Opuntia ficus-indica Mill) silage (CPS) and intermittent water supply (IWS) to crossbreed goats' diets on carcass traits and meat quality were evaluated. The IWS caused a reduction (p = 0.03) in the percentage of leg fat in the animals. The rib eye area, carcass weight, and physical-chemical characteristics were not affected (p > 0.05) by the CPS or IWS. The IWS reduced (p = 0.04) the elongase enzyme activity. The CPS inclusion in the diet reduced C22:0 (p = 0.01), some branched-chain fatty acid (BCFA), C20:1 (p = 0.03), c13-C18:1 (p = 0.01) fatty acids. Therefore, in situations of water scarcity, an intermittent water supply of up to 48 h and diets with up to 42% cactus pear silage, can be adopted in goat feedlot, without affecting carcass traits and meat quality.

Effect of crude glycerin levels on meat quality and carcass characteristics of crossbred Boer goats

This study assessed the effects of four levels of crude glycerin (0, 50, 100, and 150 g/kg dry matter (DM) basis) in the diet of Boer crossbred goat kids on the qualitative and quantitative carcass characteristics as well as meat quality. Thirty‐two crossbred, castrated Boer x undefined breed goat kids with an initial average weight of 17.8 ± 2.2 kg between 3 and 4 months of age were distributed across a complete randomized experiment with four treatments and eight replicates. The DM intake linearly decreased (p < .05) as the crude glycerin inclusion level in the diet increased. Crude glycerin levels decreased (linear effect, p < .05) empty body weight, hot dressing percentage, and cold dressing percentage. Conformation and subcutaneous fat thickness were not affected (p > .05) by dietary crude glycerin. Crude glycerin levels decreased (linear effect, p = .03) rib eye area of the Longissimus dorsi muscle, however, did not affect color, cooking loss, and shear force. The crude glycerin can be included up to 50 g/kg DM in the diet of crossbred Boer goats without negatively affecting carcass characteristics and meat quality. It can be recommended as an energy source in finishing diets.

Rumen fermentation and metabolic profile of rams fed with diets amended cottonseed cake

The aim of the study was to evaluate the addition of increasing cottonseed cake contents in the diet. The diets were composed of corn silage (500 g kg^-1) and concentrate feed (500 g kg^-1) on a dry matter (DM) basis. The treatments consisted of the substitution of 0, 140, 280, and 420 g kg^-1 soybean meal to cottonseed cake in the DM of concentrate feed. Four rams of the Santa Inês breed, average age of 12 months and average weight of 27.77 ± 3.87 kg, were distributed in a Latin square design (4 × 4) in a split-split-plot design, with diets in the plots and as subplots were 5 days of collection and the collection times. The results were subjected to analysis of variance and regression at 5% probability. The soybean meal substitution contents by cottonseed cake in the concentrate increased linearly the pH (P = 0.019). Ruminal ammonia-nitrogen concentration decreased linearly by 0.0137 mg dL^-1 at each 10 g/kg of substitution and the time after feeding promoted the same effect (P < 0.001) decreased linearly by 0.6204 mg dL^-1 at each hour after feeding. There was an increased linearly of 0.0116 mmol mL^-1 at the concentration of propionic (P = 0.008) and a reduction of 0.0062 mmol mL^-1 at the concentration of butyric (P = 0.009) with cottonseed cake content; however, the substitution did not influence the others short-chain fatty acids. Replacement of soybean meal with cottonseed cake in the sheep feed did not significantly alter the blood parameters, promoting minor changes in the ruminal parameters mainly in the ruminal ammonia-nitrogen without affecting the animal's health.

Fermentative profile, losses and chemical composition of silage soybean genotypes amended with sugarcane levels

The experiment aimed to evaluate the fermentative and nutritional profile of the silage of four soybean plant genotypes (BRS 333 RR, Pampeanas: C50, C60, and C70) ensiled with levels of sugarcane (0, 25, 50, 75, and 100%). The experiments were conducted in a completely randomized design, in factorial scheme 4 × 5 (four soybean genotypes and five levels of sugarcane inclusion) with four replicates. Silages with 100% soybean plant presented the highest levels of butyric acid (P < 0.001) and ammoniacal nitrogen (P < 0.047); however, the intermediate addition of sugarcane contributed to lactic fermentation (P < 0.001). Besides, there was a quadratic effect (P < 0.05) for the recovery of dry matter, which ranged from 83.28 to 95.29%, with higher values observed for silage with the same proportions of soybean plant and sugarcane. It was verified that the crude protein content exhibited decreasing linear effects (P < 0.001), varying among 4.60 to 7.48% in the silages. It was concluded that the highest recovery of dry matter, the best fermentation profile, and the highest levels of crude protein and digestibility occurred in the inclusion between 25 and 50% of sugarcane in soybean silage, with the superiority of the C50 soybean genotype.