In Ethiopia, the dairy cows’ major feed resources are natural pasture and crop residues, both of which are nutritionally low and do not even satisfy the maintenance requirement. Consequently, dairy productivity per head is low in the country. This paper reviews the existing knowledge of negative energy balance (NEB) and summarizes its implication on production and reproduction parameters, as well as the monitoring tools as a means of intervention in minimizing the effect on dairy cows. The presence of NEB in late gestation and early lactation of dairy cows could contribute to both short and long-term negative effects on production and reproduction ability. Lower body condition, reduced milk production, a change in the milk fat to protein ratio, an increasing incidence of health problems, a late time to become estrus, delayed ovarian cycle, and a lower conception rate are the common implications. Through the knowledge created so far, it can be concluded that NEB is almost a common phenomenon in transitional high milking dairy animals, but there is a possibility to shorten its persistence through strategic supplementation using the NEB monitoring tools.

Objective: Portable laser methane detectors (LMDs) may be an economical means of estimating CH4 emissions from ruminants. We validated an LMD-based approach and then used that approach to evaluate CH4 emissions from indigenous dairy cows in a dryland area of Ethiopia. Methods: First, we validated our LMD-based approach in Simmental crossbred beef cattle (n = 2) housed in respiration chambers and fed either a high- or low-concentrate diet. From the results of the validation, we constructed an estimation equation to determine CH4 emissions from LMD CH4 concentrations. Next, we used our validated LMD approach to examine CH4 emissions in Fogera dairy cows grazed for 8 h/d (GG, n = 4), fed indoors on natural-grassland hay (CG1, n = 4), or fed indoors on Napier-grass (Pennisetum purpureum) hay (CG2, n = 4). All the cows were supplemented with concentrate feed. Results: The exhaled CH4 concentrations measured by LMD were linearly correlated with the CH4 emissions determined by infrared-absorption-based gas analyzer (r2 = 0.55). The estimation equation used to determine CH4 emissions (y, mg/min) from LMD CH4 concentrations (x, ppm m) was y = 0.4259x+38.61. Daily CH4 emissions of Fogera cows estimated by using the equation did not differ among the three groups; however, a numerically greater milk yield was obtained from the CG2 cows than from the GG cows, suggesting that Napiergrass hay might be better than natural-grassland hay for indoor feeding. The CG1 cows had higher CH4 emissions per feed intake than the other groups, without significant increases in milk yield and body-weight gain, suggesting that natural-grassland hay cannot be recommended for indoor-fed cows. Conclusion: These findings demonstrate the potential of using LMDs to valuate feeding regimens rapidly and economically for dairy cows in areas under financial constraint, while taking CH4 emissions into consideration.

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 and Brachiaria Hybrid), and treated crop residues (Eragrostis tef straw) 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 × 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); and Brachiaria hybrid 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 (R² = 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.

The huge livestock resources of the country could not be used to its potential due to lack of good-quality feed throughout the year. Consequently, finding alternative feed supplements for livestock is an important step to sustain livestock production in the country. Ficus thonningii leaf is one of the potential feed resources for ruminants in the area. The experiment was conducted with the objective of evaluating the nutrient intake, digestibility and growth performance of local lambs fed natural pasture hay (NPH)-based diet supplemented with graded levels of Ficus thonningii dried leaves (FTL) and determining of the optimum level for replacing of concentrate mixture (CM). Twenty intact male yearling Washera lambs with initial body weight of 17.06 + 1.43 (mean + SE) kg were used in experiment. The experiment was conducted using randomized complete block design having four replications with five dietary treatments. The treatments were T1 = NPH + 0 g FTL +215 g CM; T2 = NPH + 112.5 g FTL +161.25 gCM; T3 = NPH + 225 g FTL +107.5 g CM; T4 = NPH + 337.5 g FTL + 53.75 g CM; and T5 = NPH + 450 g FTL +0 g CM. Data were analyzed using the general linear model procedures of SAS (version 9.3; 2002). The results showed that FTL are a good source of crude protein (CP) (126.9 g/KgDM) and fibers (377–426 g/Kg DM). Results also showed that supplementation of higher-level FTL significantly (P < 0.001) increased total DM, OM and fibers intake (P < 0.001), but no significant difference (P > 0.05) observed in CP and ME intakes among treatments. Increasing level of FTL supplementation, however, reduced significantly (P < 0.001) the digestibility coefficient of all nutrients. In terms of ADG, nonsignificant (P > 0.05) differences were observed in lambs assigned up to 75% replacement of CM. The lowest performance was observed in sole FTL supplementation (T5), despite increased nutrients intake. It was concluded that indigenous fodder tree Ficus thonningii leaves could serve as alternative CP supplement in NPH-based feeding of Washera sheep and can be used to replace CM up to 75% to improve performance.

This study was conducted in Fogera District, north western Ethiopia, to evaluate the effect of harvesting stages on biomass yield and nutritive value of oat–vetch mixtures under residual moisture. The experimental plots were prepared thoroughly by plowing the land before sowing. The experiment was conducted using randomized complete block design in a factorial arrangement having two factors with three replications. The first factor, factor A, comprises a four combinations of two forage species (oats and vetches) having two varieties each. The two oats varieties used were CI-8237 and CI-8251, represented as (O₁) and (O₂) and the two vetch varieties, Vicia villosa and Vicia dasycarpa, represented as V1 and V2, respectively. The second factor, harvesting stage, had three levels which follows the three physiological stages of oat varieties as flag leaf stage (HS₁), milk stage (HS₂) and dough stage (HS₃) in the mixtures. Agronomic performance and forage biomass yield were recorded. Chemical compositions of the forage such as crude protein (CP), ash, neutral detergent fiber, acid detergent fiber, acid detergent lignin, hemicellulose and cellulose were determined. Data were analyzed with general linear model procedure of SAS (version 9.1; 2008). Results indicated that harvesting stages significantly (P < 0.001) affected most of the agronomic parameters in oats varieties, whereas plant height and number of branches were significant (P < 0.05) in vetch varieties. Significantly higher (P < 0.001) plant height, number of leaves per plant and leaf to stem ratio) were obtained in variety oats CI-8237. Dry matter yield (DMY) and chemical compositions of the forage were significantly affected (P < 0.001) by harvesting stages. More vigor and higher number of branches were recorded in V. villosa, but higher plant height was obtained in V. dasycarpa. The highest mean DMY (4.99 t/ha) and CP yield (0.81 t/ha) were recorded at harvesting stage two (HS₂). However, the lowest DMY (3.42 t/ha) was obtained at harvesting stage one. Relatively, the optimum DMY (6.16 t/ha) with maximum CP yield (0.92 t/ha) was recorded from mixture of CI-8237 + V. villosa at harvesting stage two. The fiber components were increased with advanced stage of growth, but CP and ash contents were decreased as the age of the plant matures. Production of CI-8237 + V. villosa mixture harvested at harvesting stage two would be more beneficial to produce optimum yield and nutritive value and could be recommended in the study area.

This experiment was conducted with the objective of evaluating the effects of intercropping vetch species and harvesting age on the morphological characteristics, forage yield, and chemical composition of sole and intercropped forages. The experiment was laid out using a randomized complete block design (RCBD) in a factorial arrangement consisting of two factors ((five forage varieties (four vetches & one desho) *two harvesting ages)) for a total of ten treatments with three replications. The experimental treatments were sole desho (Var-Kulumsa), desho+V. villosa (Var-Lalisa), desho+V. villosa (Var-Gebisa), desho+V. sativa, and desho+V. dasycarpa (Var-Lana) at 90 and 120 harvesting days. All morphological characteristics forage yield and chemical composition data were collected from two middle rows by excluding the border rows. The result showed that the interaction (P < 0.001) effect of harvesting age and intercropping of vetch species and varieties with desho grass was observed on the morphological characteristics, dry matter yield, and chemical composition of intercropped forage. Intercropping of vetch species/varieties with desho grass had shown significantly (P < 0.001) higher dry matter yield than sole desho except desho with V. sativa. The highest crude protein (CP) content was obtained from desho grass intercropped with two V. villosa (Var-Lalisa and Var-Gebisa) at 90 days of harvesting age. This CP content of intercropped desho+Vetch species/varieties was double in amount than the CP obtained from sole desho in these species at 90 days of harvesting age. Moreover, the highest CPY was recorded from two V. villosa varieties (Var-Lalisa and Var-Gebisa). Hence, for the intercropping of vetch with desho grasses, the two V. villosa varieties (Var-Lalisa and Var-Gebisa) are recommended for on-farm evaluation and demonstration in the study area and similar agro-ecologies during the establishment phase at 90 days of harvesting age. It is possible to conclude that the intercropping of desho with these selected vetch species could be better than sole desho grass in terms of forage yield and quality in the highlands of northwestern Ethiopia to maximize ruminant livestock production. Hence, for the intercropping of vetch with desho grasses, the two V. villosa varieties (Var-Lalisa and Var-Gebisa) are recommended for on-farm evaluation and demonstration in the study area and similar agro-ecologies during the establishment phase at 90 days of harvesting age.