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.

Ingestive behavior of Girolando steers supplemented on tropical pastures

In this study, we evaluated the feeding behavior of Girolando steers on Brachiaria brizantha cultivar Marandu pastures. Twenty-two animals with an average initial weight of 209.09 ± 8.18 kg were distributed in a completely randomized design in a 3 × 2 factorial arrangement (three seasons and two nutritional plans (NP)) with 11 replicates, as follows: rainy season 1 (NP1, mineral mixture ad libitum, and NP2, nitrogen/energy supplement [2 g.kg^‒1 body weight [BW]]); dry season (NP1, nitrogen/energy supplement [1 g.kg^‒1 BW], and NP2, nitrogen/energy supplement [2 g.kg^‒1 BW]); and rainy season 2 (NP1, mineral mixture ad libitum, and NP2, nitrogen/energy supplement ([1 g.kg^‒1 BW]). Total chewing time was longer in NP1 (566.44 vs 528.33 min.day^‒1 in NP2) (p < 0.05). The grazing, idle, trough, and total chewing times were affected by the interaction between nutritional plans and seasons. The period expended grazing was longer for the NP1. The idle time was affected by the nutritional plans and was lower for the NP1. Feeding at the trough was not affected by the nutritional plans. The animals of the NP2 showed the highest feed efficiencies in DM and NDF (0.91 and 0.52 vs 0.75 and 0.45 in NP1, respectively). Rainy season 2 had the highest efficiencies. The feeding behavior changes according to the supplementation level. Nutritional plan 2 in the second rainy season presented the best results.