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

Simple Summary In tropical regions, it is common practice to feed dairy cows poor-quality roughage, but this diet has been shown to decrease animal productivity and increase methane emissions. For these reasons, introducing alternative roughage feeds, such as nutritionally improved forages or bio-chemically treated straw, is essential for improving milk yield, dietary nitrogen utilization, and reducing enteric methane emission from dairy cows. Thus, we evaluated the effects of natural pasture hay, two improved grass hays (Napier andBrachiariahybrid grasses), and treated teff straw silage feeding as basal diets on nutrient digestibility, milk yield, nitrogen utilization efficiency, and enteric methane emissions using lactating Fogera dairy cows. Our results showed that improved grass hays and treated teff straw silage diet feeding increased milk yield, nutrient digestibility, and nitrogen utilization efficiency as compared to natural pasture hay. Moreover, the cows fed with improved grass hays and treated teff straw resulted in changing the nitrogen excretion pathway from urine to feces, as well as reduction of the methane production per daily milk yield. Hence, these results provide a novel feeding regimen through feeding nutritionally upgraded forages as a basal diet, which improves milk yield, nutrient utilization efficiency, and reduction of methane emission for sustainable dairy production in tropical regions. The nutritionally imbalanced poor-quality diet feeding is the major constraint of dairy production in tropical regions. Hence, alternative high-quality roughage-based diets are required to improve milk yield and reduce methane emission (CH4). Thus, we tested the effects of feeding natural pasture hay, improved forage grass hays (Napier andBrachiariaHybrid), and treated crop residues (Eragrostis tefstraw) on nutrient digestibility, milk yield, nitrogen balance, and methane emission. The eight lactating Fogera cows selected for the experiment were assigned randomly to a 4 x 4 Latin square design. Cows were housed in well-ventilated individual pens and fed a total mixed ration (TMR) comprising 70% roughage and 30% concentrate. The four roughage-based basal dietary treatments supplemented with formulated concentrate were: Control (natural pasture hay (NPH)); treated teff straw silage (TTS); Napier grass hay (NGH); andBrachiariahybrid grass hay (BhH). Compared with the control diet, the daily milk yield increased (p< 0.01) by 31.9%, 52.9%, and 71.6% with TTS, NGH, and BhH diets, respectively. Cows fed BhH had the highest dry matter intake (8.84 kg/d), followed by NGH (8.10 kg/d) and TTS (7.71 kg/d); all of these intakes were greater (p= 0.01) than that of NPH (6.21 kg/d). Nitrogen digestibility increased (p < 0.01) from the NPH diet to TTS (by 27.7%), NGH (21.7%), and BhH (39.5%). The concentration of ruminal ammonia nitrogen was higher for cows fed NGH than other diets (p= 0.01) and positively correlated with plasma urea nitrogen concentration (R-2 = 0.45). Feeding TTS, NGH, and BhH hay as a basal diet changed the nitrogen excretion pathway from urine to feces, which can help protect against environmental pollution. Estimated methane yields per dry matter intake and milk yield were decreased in dairy cows fed BhH, NGH, and TTS diets when compared to cows fed an NPH diet (p< 0.05). In conclusion, feeding of TTS, NGH, and BhH roughages as a basal diet to lactating dairy cows in tropical regions improved nutrient intake and digestibility, milk yield, nitrogen utilization efficiency, and reduced enteric methane emission

Nutritional Value and In Vitro Volatile Fatty Acid Production of Forage Grasses Cultivated Using Farmyard Manure and Desmodium intortum Intercropping in the Upper Blue Nile Basin, Ethiopia

Integrating farmyard manure (FYM) and legume intercropping improves soil chemical and microbial properties, thereby increasing forage productivity and nutritional value. The purpose of this study was to evaluate how fertilizer treatments affected the chemical composition, in vitro gas production and organic matter digestibility (IVOMD), and volatile fatty acid production (VFA) of Napier and desho grasses in the upper Blue Nile basin of Ethiopia. Apart from ether extract content, the chemical composition of the fertilizer treatments in the Aba Gerima watershed did not differ significantly, whereas significant differences were observed in acid detergent fiber and crude protein contents at the Guder watershed. In both watersheds, Napier grass had significantly higher crude protein levels than desho grass. In Aba Gerima, ash content was significantly higher in 2018 than in 2019, but not in Guder. For Napier and desho grasses, there were an increment in IVOMD (6.7 vs 4.7%), metabolizable energy (5.5 vs 4.5%), and VFA production (23.1 vs 3.0%) in the Desmodium intortum plus FYM treatment than in the control in Aba Gerima. In Guder, however, IVOMD (13.7 vs 4.6%), metabolizable energy (13.3 vs 3.3%), and VFA production (11.2 vs 5.6%) increased in the same treatment for Napier and desho grasses than in the control. This study suggests that the Desmodium intortum plus FYM improves the nutritional value, IVOMD, and VFA production of Napier and desho grasses in dryland areas of the upper Blue Nile basin, facilitating their growth as alternative livestock feed for better production in these areas

Selection and evaluation of promising indigenous fodder trees and shrubs as supplemental diets for ruminant animals across different agroecological environments

The aim of this study was to select and evaluate promising potential indigenous fodder trees and shrubs (IFTS) as supplemental feeds for ruminant animals. Through interviews with farmers and field inventories, 107 IFTS species were identified as ruminant feeds, from which 37 potential IFTS species were selected. The chemical composition and anti-nutritional factors of the selected IFTS were analysed. Among the 37 selected IFTS species, crude protein (CP) ranged from 83.3 to 230.5 (mean, 134.3) g kg−1 dry matter (DM); CP was greater than 80 g kg−1 DM in all selected species. Condensed tannin (CT) content varied from 2.57 to 210.91 g kg−1 (p −1 DM, an amount that is tolerable for ruminants. Farmers’ preferences and the nutritive value of the selected fodder species were positively correlated (p 110 g kg−1, neutral detergent fibre (NDF) −1, and CT −1. Thus, the selected potential IFTS need further evaluation for their agronomic practice, biomass production and animal performance.</p