Comparison of yield, nutritive value, and in vitro digestibility of monocrop and intercropped corn-soybean silages cut at two maturity stages

Dallisgrass ( Paspalum dilatatum Poir.) is an economically important and widely cultivated forage crop for livestock feeding in the tropical, subtropical, and warm temperate regions because of good adaptation to unsuitable pasture conditions. In this study, 216 dallisgrass samples were used to develop near infrared reflectance calibrations to estimate five forage quality parameters: dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and ash. Second derivative pretreatment was applied for calibration of DM, CP and NDF while a first derivative pretreatment was used for ADF and ash. The coefficients of determination in the internal validation set (r ²) were 0.78 for DM, 0.80 for CP, 0.95 for NDF 0.75 for ADF, and 0.71 for ash. The relative predictive determinant ratios for calibration indicate that the NDF equations were acceptable for quantitative prediction of dallisgrass quality, whereas the DM, CP, ADF, and ash equations were useful for screening purposes. The near infrared prediction models developed in this study can be used for screening in the forage breeding researches to be carried out for five quality parameters in the future.

The primary aim of this research was to assess the impact of supplementing fish oil into the diet of pregnant Awassi ewes on various aspects of the dam’s productive performance, offspring birth weight, colostrum yield and quality, milk production and composition, postpartum offspring performance, and the composition of fatty acids in milk. In this study, two different fat sources, namely palm oil (PO) and fish oil (FO), were utilized, with both being included at a rate of 2.4% of dietary dry matter (DM) during the initial 65 days of gestation (early gestation stage), and then at 2.1% DM from day 65 of gestation until lambing (late gestation stage). The study subjects were Awassi ewes with a body weight (BW) averaging 57 ± 1.5 kg and an age of 3.5 ± 1.2 years. These ewes were randomly assigned to one of four dietary treatments: (i) a diet containing only palm oil from day 0 to day 150 of pregnancy (PO, n = 15); (ii) a diet containing palm oil from day 0 to day 65 of pregnancy, followed by a diet containing fish oil from day 66 to day 150 of pregnancy (POFO, n = 16); (iii) a diet containing fish oil from day 0 to day 65 of pregnancy, followed by a diet containing palm oil from day 66 to day 150 of pregnancy (FOPO, n = 16); (iv) a diet containing only fish oil from day 0 to day 150 of pregnancy (FO, n = 16). Within each treatment, ewes were housed in three replicates, with each replicate further divided into three subgroups. The first two subgroups each contained eight ewes, while the third subgroup contained nine ewes. In addition, each treatment contained 10 primiparous and 15 multiparous ewes. The results indicated that the POFO treatment led to significant increases (p < 0.05) in birth weight, gestation length, and colostrum IgG concentration. However, it also resulted in a decrease (p < 0.001) in colostrum production and a reduction (p < 0.001) in the percentage of milk fat and milk protein. Furthermore, the milk from the POFO treatment exhibited higher levels of polyunsaturated fatty acids (PUFAs) (p < 0.001) compared to the PO and FOPO treatments, while the milk saturated fatty acids (SFA) were lower (p < 0.001). In conclusion, the addition of fish oil at a rate of 2.1% DM during the late pregnancy period showed promise for enhancing birth weight, colostrum IgG concentration, and the PUFA content in the milk.

Feed additives are essential in advancing modern ruminant nutrition by addressing challenges related to productivity, environmental sustainability, and animal health. This chapter explores the diverse roles of feed additives in optimizing rumen fermentation, enhancing nutrient utilization, and reducing methane emissions within evolving global livestock production systems. It provides a comprehensive classification of additives—including buffers, ionophores, probiotics, enzymes, tannins, essential oils, and rumen-protected nutrients—detailing their mechanisms for improving feed efficiency and mitigating environmental impacts. The integration of these additives with nutritional models and emerging innovations such as microbial precision engineering and algae-based solutions is examined. While feed additives demonstrate significant benefits, challenges remain in economic feasibility, regulatory compliance, and global accessibility. Future directions emphasize precision nutrition approaches and the development of scalable solutions to ensure a sustainable livestock sector that meets growing global demand.

The present study was conducted to evaluate whether the deacetylation degree of chitosan (low: 70% vs. high: 90%) and its dietary level (0, 200, 400, 800, 1600 mg/kg diet) would affect laying performance, faeces viscosity, egg quality, egg and serum biochemistry of layers. For the experimental feeding period of 8 weeks, 140 four weeks old Hisex Brown layers were divided into 10 treatment groups, comprising 14 birds each. The birds were housed in individual cages in a complete randomised design. Performance was assessed by recording feed intake, egg weight, daily egg production, egg quality and egg biochemistry. Serum biochemistry parameters were determined at the beginning and end of the experiment and faeces viscosity at the end of the experiment. Feed conversion ratio and faeces viscosity were deteriorated by increased level of chitosan. Lightness of egg yolk was significantly increased in animals receiving high-degree deacetylated chitosan compared to low-degree deacetylated chitosan. Yellowness of egg yolk was affected by interaction of deacetylation degree and level of chitosan. Yolk cholesterol concentration was lower in groups receiving high deacetylated chitosan by increasing chitosan level, while laying hens fed low deacetylated chitosan had a higher level of yolk cholesterol. A significant interaction between degree of deacetylation and chitosan level was determined for serum glucose and calcium concentration. Serum total antioxidant content increased with higher levels of dietary chitosan. In conclusion, dietary level or different degrees of deacetylated chitosan may reduce yolk cholesterol and improve serum antioxidant status. However, feed conversion ratio and faeces viscosity were impaired by increasing levels of chitosan supplementation, and lightness of yolk was increased by supplementation of chitosan with a high degree of deacetylation.