Effects of supplementing cassava root silage to grazing dairy cows on nutrient utilization, milk production and composition in the tropics

The current study evaluated the effects of supplementing cassava root silage (CRS) to dairy cows grazing on Megathyrsus maximus cv Mombasa on nutrient intake and digestibility, as well as on milk production and composition. Ten primiparous Girolando cows with average body weight ± (SEM) of 373.45 ± (63.55) kg were used in a replicated 5 × 5 Latin square. Animals were subjected to five treatments: (I) grazing cows without supplementation (WCS); (II) grazing cows provided with 5 kg DM of supplement without CRS (0 g/kg DM of CRS) or including (III) 260, (IV) 520, and (V) 780 g/kg DM of CRS. Statistical analyses were performed using the PROC MIXED of SAS with significance at P < 0.05. Intake of neutral detergent fiber (NDF) and ether extract decreased (P < 0.01), while intake of non-fiber carbohydrates increased (P < 0.01), with increased CRS in the diets. Total DM intake and digestibility of DM, and digestibility of nutritional components were lower (P < 0.03) in WCS animals compared to supplemented animals, except for intake and digestibility of NDF, which was the opposite. Milk yield (MY) and fat corrected milk (FCM), as well as all milk components were unaffected (P > 0.05) by CRS inclusion. In contrast, MY, FCM, protein, lactose, casein, and non-fat milk solids (NFMS) were greater for animals that received supplementation (P < 0.05), compared to animals WCS. Milk fat and total dry extract (TMS) did not differ (P > 0.11) between two groups. In conclusion, CRS may be a potential corn meal replacer in the supplement of dairy cows under tropical conditions.

Effect of Dietary Palm Kernel Oil on the Quality, Fatty Acid Profile, and Sensorial Attributes of Young Bull Meat

Lipid supplementation through vegetable oils in diets for ruminants can be a nutritional strategy to increase energy density, manipulate ruminal fermentation and change the physicochemical composition and sensorial properties of meat. This study evaluated the optimal dietary inclusion of palm kernel oil (PKO) for Nellore bulls on meat quality. The diets consisted of 0.0, 11.5, 23.0, and 34.6 g/kg dry matter (DM) PKO levels. PKO inclusion did not influence the centesimal composition, pH, color indices, water holding capacity, cooking loss, or shear force of the beef. There were linear increases in the concentrations of lauric acid (C12:0) and myristic acid (C14:0) in the bull's meat. However, palmitic acid (C16:0), oleic acid (C18:0), vaccenic acid (t-11-C18:1) and conjugated linoleic acid (CLA), ∑n - 6, ∑n - 3, ∑n - 6/∑n 3, the hypocholesterolemic: hypercholesterolemic ratio of the fatty acid content, and the thrombogenicity index were not affected. There were linear reductions in the oleic acid meat concentration (c-9-C18:1) and elongated enzymatic activity when PKO was added to the bull diet. The atherogenicity index increased linearly due to PKO inclusion in the bull diet. No effect of the inclusion of PKO on meat flavor, perception of tenderness, juiciness, or global acceptance from the sensorial evaluation was recorded. The inclusion of PKO up to 34.6 g/kg DM can be recommended to supplement young bulls with no effects on meat composition and quality characteristics.

Effects of condensed tannin-amended cassava silage blend diets on feeding behavior, digestibility, nitrogen balance, milk yield and milk composition in dairy goats

Condensed tannins (CTs) are phenolic compounds derived from secondary plant metabolism that act as part of the plant's chemical defense system against pathogen invasion and herbivorous attack. This study aimed to evaluate the intake, digestibility, nitrogen (N) balance, production and composition of milk from goats fed cassava silage with added levels of CTs. Eight Anglo-Nubian goats with a mean BW of 40 ± 2.0 kg were distributed in a double Latin square design with four levels of CTs (0, 25, 50 and 75 g/kg DM) with four 20-day periods with 15 days of adaptation and five evaluation days for each period. No differences were observed in DM, NDF, CP intake and feed conversion (grams of DM intake (DMI) per gram of milk produced); however, when expressed as percent of BW, DMI showed a quadratic increase to 29.1 g/kg. As the level of supplemented CTs increased in the diet, the CP digestibility (P = 0.023), NDF (P = 0.044), non-fiber carbohydrates (NFC; P = 0.032) and total digestible nutrients (P = 0.033) exhibited a linear decrease. Furthermore, the addition of CTs to cassava silage induced a linear increase in N-fecal excretion (P = 0.014) and a positive quadratic effect on N-retained (P = 0.014) and N-balance (P = 0.024) as well as a positive quadratic trend in N-digested (P = 0.092). Milk urea N (P = 0.023) decreased linearly. The addition of CTs to cassava silage had a positive quadratic effect on ruminating time (P = 0.011). In addition, comparing the use or non-use from the orthogonal contrast test, the inclusion of CTs in goat diet increased water and N-intake, CP and NDF digestibility, spent time eating and ruminating and N-balance and decreased milk production corrected^3.5%, fat milk content, milk urea N and dry defatted extract of milk. Thus, adding CTs to cassava silage at 25 g/kg total DM promoted goats' greater use of the diet without impairing feed conversion and the quality of goat milk produced. Dietary levels of 50 and 75 g/kg total DM are not recommended because under the conditions of this study, they reduced the productive efficiency of dairy goats.