In the mixed crop-livestock farming system of Ethiopia, natural pasture production is related to seasonal rainfall distribution which is restricted to only a few months of the year. Livestock owners in this country experience periods of excess forage in the rain season where preserving it through haymaking became tradition as a strategy for the periods of scarcity, particularly the dry season of a year. Forage can also be stored as standing hay, the cheapest way of conserving forage, in a place like pastoral and agro-pastoral production system where a decline in quality can be tolerated. Mixed grass-legume pasture samples from different agro-ecology were collected and portion of the samples were analyzed conventionally to determine their chemical composition (dry matter, ash, crude protein, neutral detergent fiber, acid detergent fiber, lignin) and in vitro dry matter digestibility to validate the NIRS calibration. NIRS was evaluated by the coefficient of determination in calibration (R 2), standard error of calibration (SEC), and standard error of cross validation (SECV). The results showed NIRS is extremely useful for predicting nutrient contents as compared to conventional chemical analysis methods which are not difficult to conduct, but they are expensive in terms of time and resources.

This study was conducted to generate information on the dynamics in nutritional qualities of natural pasture hay as affected by harvesting stage, storage method and storage duration at Holetta representing cool tropical environment in the central highlands of Ethiopia. The study was designed with a factorial combinations of four harvesting stages/times (mid-October, late-October, mid-November, late-November), two storage methods (open-air, shelter shade) and five storage durations (zero, two, four, six and eight months). Crude protein (CP), in vitro OM digestibility (IVOMD), metabolizable energy (ME), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin contents in the hay were significantly (P < 0.05) affected by harvesting stages, storage methods and storage durations. The mean CP content was reduced by 30.2%, while both IVOMD and ME contents were reduced by 17.8% each with the delay in harvesting time from mid-October (full heading stage of the pasture) to late-November (one and half months past the full heading stage). On the other hand, the mean of NDF, ADF and lignin contents were increased by 13.8, 21.6 and 36.0%, respectively with the delay in harvesting time within the specified periods. Harvesting during late-October resulted in higher yields of DM (6.83 t/ha), CP (0.48 t/ha) and digestible OM yield (3.77 t/ha) than the other harvests suggesting that late-October is the ideal harvesting time for producing large quantity of better quality hay from natural pasture in the area. The nutritional qualities of the hay also showed considerable dynamism during the eight months storage period both under shade and in open air storage methods. However, the regression analysis indicated that daily rates of changes in nutritional qualities (the rates of decline in CP content and IVOMD, and the rates of increase in the fiber fractions) during storage were higher when the hay was stored in open air than under shade. The result generally showed that in terms of contents of the important nutritional parameters (CP, IVOMD, ME, NDF, ADF and lignin), hay-based feeding could be detrimental to the nutrition of dairy cattle with the delay in harvesting beyond the late-October. Substantial reductions in nutritional qualities were also observed during storage with higher rates of nutrient losses when the hay was stored in open-air than under shade. Therefore, current findings should be supported by further animal performance studies in order to establish proper supplementation schemes considering harvesting stage, storage method and storage duration in haybased feeding system of dairy cattle in the highlands of Ethiopia.

No abstract

This study was conducted to examine the effect of different wheat straw and concentrate proportions on feed intake, nutrient digestibility, growth and reproductive performances of F1 cross breed (Boran X Friesian) dairy heifers. Wheat straw (WS) with 93% dry matter content was chopped (3-5 cm in length) and mixed with concentrate, molasses and water. The amount of water used for the preparation of total mixed ration was three fold of the molasses amount. Twelve dairy heifers (90.45 ± 7.37 kg LW, mean ±S.D) were randomly assigned to one of the three dietary treatments (WS80= 80% WS: 20% concentrate; WS60 = 60% WS: 40% concentrate) and WS40 = (40% WS: 60% concentrate) in a completely randomized block design. The diets were offered ad-libitum and allowing 15-20% refusal. The experiment was consisted of 345 days of feeding trial and 7 days for the measurement of digestibility. Different wheat straw and concentrate proportion had no significant effect on organic matter intake of dairy heifers. In contrast, dry matter (DM), crude protein (CP) and acid detergent fiber (ADF) and neutral detergent fiber (NDF) intakes were greater when the heifers were fed WS40 versus the other treatments. The greater (P<0.001) DM, CP, ADF and NDF digestibility, feed conversion efficiency and growth rate were observed in WS40 than the other treatments. The greater (P<0.001) body weight at first service for dairy heifers was perceived in WS80 than the other dietary treatments. Conversely, the smallest age at first service, age at first conception and number of service per conception for dairy heifers was noticed in WS40 than the other dietary treatments. Raising dairy heifers by using 40% wheat straw and 60% concentrate can be recommended for practical application.

Brewers’ spent grain (BSG) is the amplest by-product of the brewing process. The fresh BSG is currently used as low-cost cattle feed due to its microbiological instability and high perishability. While recent research looked at the effects of storage time and temperature on the characteristics of wet brewers grains (WBG) as ruminant feeds. Three storage temperatures (15, 20, and 25 °C) and periods (2, 4 and 6 days) were arranged in a 3 × 3 factorial design. Surface spoilage was not apparent at 15 °C throughout the storage periods. Deterioration was not also observed at 20 °C until the fourth day of storage where slight mold growth was apparent. Extensive mold growth was detected late in the sixth day at 20 °C and continued manifestations up until the last day of storage at 25 °C. Changes in major nutrients, DM losses, and yeast and mold colony count were significantly affected by the interaction of storage temperatures and durations (P < 0.05). Except for samples stored at 15 °C, nutrients contents decreased concomitantly (exceptions are ADF, lignin, and loss in DM) with prolonged storage times (p < 0.05) and increasing temperatures (p < 0.05). Contrast analysis indicated that it would be safe to store under aerobic storage conditions and feed the WBG for dairy cattle.