Supplementing Tropical Cattle for Improved Nutrient Utilization and Reduced Enteric Methane Emissions

Abstract

Given their high nitrogen (N) concentration and low costs, sweet potato vine silage (SPVS) and urea-molasses blocks (UMB) are recommended supplements for tropical regions; therefore, they were investigated in this study. Six heifers were allocated to three diets: the roughage diet (R) consisted of wheat straw (0.61) and Rhodes grass hay (0.39; on dry matter (DM) basis); R + SPVS combined R (0.81) and SPVS (0.19); and with R + UMB animals had access to UMB. During two experimental periods, feed intake, feces and urine excretion, digesta passage, and rumen microbial protein synthesis were determined during seven days and methane emissions during three days. There was no treatment effect (p > 0.05) on DM and N intake. Apparent DM digestibility of R + SPVS (510 g/kg) was higher (p < 0.05) than of R (474 g/kg). Digesta passage and duodenal microbial N flow were similar for all diets (p > 0.05), while N retention was highest with R + SPVS (p > 0.05). Methane emissions per unit of digested feed (g CH4/kg dDM) were lower (p < 0.05) for R + SPVS (55.2) than for R (64.7). Hence, SPVS supplementation to poor–quality roughage has the potential to increase diet digestibility and N retention while reducing CH4 emissions.

Effects of Inclusion Levels of Sweet Potato Vine Silage on Feed Intake, Milk Production and Profitability of Lactating Crossbred Dairy Cows

“…The findings are in agreement to those observed by [17], and [4]. This was due to increased DMI hence more nutrient ingestion and nitrogen utilization with SPVS supplementation [3]. Fat corrected milk content improved with SPVS supplementation though there was no consistent trend across the four levels of SPVS supplementation.…”

“…These sweet potato vines can effectively be utilized as dairy cattle feed. The value of sweet potato vines is attributed to their inherent characteristics that include high levels of water-soluble carbohydrates, palatability, crude protein and high digestibility (>62%) [3]. The crude protein content of sweet potato forage ranges from 180 to 300 g/kg dry matter among different varieties, while the crude fiber content is about 180 g/kg DM.…”

Effect of Feeding Improved Grass Hays and Eragrostis tef Straw Silage on Milk Yield, Nitrogen Utilization, and Methane Emission of Lactating Fogera Dairy Cows in Ethiopia

“…Moreover, owing to an alarmingly rising human population, grazing lands used for natural hay production for the dry season are widely converted to croplands and plantations [ 2 ], thereby forcing cattle to graze on marginal and overgrazed lands with poor-quality forage [ 3 , 4 ]. This practice is further aggravated by the fact that the yield and nutritive value of tropical grasses decline sharply as the dry season approaches, leading to reduced feed intake and milk production in conventional grazing systems [ 5 , 6 ]. In addition, compared with those elsewhere, dairy animals in developing countries produce more methane and excrete more nitrogen per unit of animal product, primarily because of the feeding of low-quality roughage, which is unbalanced in nutrients [ 7 ].…”

Nutrient Content Assessment of Six Citrus Species Parts and their Feedstuff Significance

“…This indicated that leaves of these Citrus species could be used as protein supplement to enrich animal feed, because protein is needed by animal body in large amounts. Sweet potato vine silage contained 136.1 g kg -1 DM crude protein and had been suggested for supplementing tropical cattle [26]. Soybean contained 44% [27] and 49.0-52.0% crude protein value [21].…”