On-farm Effect of Urea Treated Straw and Urea

On-farm study was conducted to evaluate the effects of urea treated straw and urea molasses block on milk yield, milk composition, feed intake and body weight gain of cross-bred lactating dairy cows in urban and peri-urban dairy production system of Lume District. Three treatments were considered: a. T1: urea treated straw + concentrate b. T2: urea molasses block + untreated teff straw + concentrate c. T3: untreated straw + concentrate. Pre-visit was made and 40 cross-bred dairy cows with 2nd and 3rd parities were selected and assigned to treatments. Highly significant differences were observed. Least square mean of total DM intake was 10.58 ± 0.09, 10.18 ± 0.08 and 10.1 ± 0.1 for T2, T1and T3 respectively. Daily weight gain was higher in T1 (0.28 ± 0.03 kg) and followed by T2 (0.16 ± 0.04 kg per day) and T3 (0.02 ± 0.04 kg per day). The daily milk yield was high in T2 (10.06±0.10 L per day) and followed by T1 (9.61±0.11L per day) and T3 (8.701±0.09L per day). In conclusion urea molasses block (T2) has showed increased daily DM intake and daily milk yield. Therefore, use of urea molasses block for dairy animals will be effective in urban and peri urban area where milk market access is available. Therefore, the smallholder farmers and commercial milk producers advised to use UMB to improve milk production of cross-bred dairy cows.


Introduction
The total cattle population in Ethiopia is estimated to be about 57.83 million. Out of this, the female cattle constitute about 55.38 percent [1]. Dairy cattle produce milk which serves as nourishment for new born calves and as food for infants and also for adult humans [2]. However, dairy productivity is very low [2], due to shortage feed both in terms of quantity and quality that hindering the development of dairy industry in Ethiopia. Dairy animals suffer most by the feed shortage and their peak lactation is largely affected.
On the other hand, residues of cereals and pulses account for about 31.29percent of the total animal feed utilized and ranked second to grazing (55.33%) in Ethiopia [1]. However, their potential is limited due to their high fiber, low protein, mineral and vitamin content. Increasing efficiency of available feed resource such as crop residue treatment and nutrient supplementation are one of the appropriate methods that improve milk production [3,4]. The cost-benefit analysis and feasibility of using ammoniated straw and urea molasses block as animal feed in Ethiopia was reported by [3] & [4] respectively for crossbred lactating dairy cows.
Lume district has a considerable potential and opportunities for development of improved smallholder dairy production and is market-oriented. However, there is limited information on the use of urea treated straw and urea molasses block as comparative alternative strategy to improve the nutritive value of low quality roughages and to increase milk production of dairy cows in the area. Therefore, this study was designed to evaluate the on farm effects of urea treated teff straw and urea molasses blockon crossbred dairy animals at Lume District, East Shewa Zone.

Area Description and farmers selection
The study was conducted in Lume district (urban and periurban areas), East Shewa Zone. The district 70km away from Addis Ababain south direction. The districts altitude ranges from 1500 to 2300 meters above sea level. Farm observation was done and farmers keeping cross-bred lactating cow were selected purposively and trained on general management of dairy cows including urea molasses block and urea treated straw preparation and feeding. Discussion with local development agents was held on intervention approaches and systematic coaching

Experimental animals and treatments
Forty lactating cross-bred dairy cows at early to mid-lactation (about 5-8 weeks after calving) were selected purposively for the on-farm feeding trial based on farmers willingness to undertake the experiment and commitment for data collection, and monitoring of feed intake and milking. Average body weight of the selected cows was ranging from 287 to 377kg with an average initial milk yield ranging from 5 to 11kg/cow/day. The selected cows were in second and third parity and treated for internal and external parasites. Three treatment groups were considered (Table 1). Dairy cows were assigned and fed for a period of 45 days to collect feeding response data and with an adaptation period of 15 days. All cows have free access to water. The initial and final body weights of the experimental cows were estimated using heart girth measurements.

Experimental feed preparation and laboratory analysis
5.3.1. Urea treated teff straw: The straw was treated with a urea solution prepared from 4% of urea, 10% of molasses and 100 liters water per 100kg of air-dried straw and, incubated in pit. The wall of the pit was covered with polyethylene sheet. The straw was treated, trampled and compacted batch by batch until filled to the pit capacity. Finally, the pit was sealed with plastic sheet and loaded on top by mass of soil to make it airtight. It was, then, left unopened for twenty-one days. By the end of incubation period, the pit was opened and a portion of the straw was taken daily and ventilated overnight to remove residual ammonia before offering to the animals.
A concentrate mix that has been assumed to be sufficient for the entire experimental period was formulated based on milk yield (0.5kg per 1 liter of milk yield per day) [5]. A concentrate was mixed from 25% maize, 44.6% wheat bran, 5.8% nougseed cake, 14.4% soyabean, 2.6% nora (mineral source specially, calcium carbonate), 0.7% salt and 6.9% molasses.

Urea molasses block: UMB was formulated from 10%
noug seed cake, 25% wheat bran, 10% cement, 40% molasses, 10% urea and 5% common salt. Additionally, 4% of water (of total weight) was mixed to make a block weighing 5kg. The mixture finally had a dough texture and was put into a plastic sheet lined, oval can for molding. Compaction was applied using a wooden bar; afterwards the block was left for 15 minutes until it maintained a proper shape. Finally, it was removed from the can and left to dry in a well ventilated room for about 72 hours, after which it was ready for feeding.
All samples of feed offered were analyzed for DM, ash, neutral detergent fiber (NDF) and acid detergent fiber (ADF) as per the methods of Van Soest and Robertson. Hemicellulose was calculated from the difference between NDF and ADF.
For milk yield analysis a daily milk record (morning and afternoon separately) was taken by individual farmers themselves and enumerator. All the cows were hand milked twice a day (7:00 AM in the morning and 4:00 PM in the afternoon) and milk yield measurements were taken by using graduated cylinder every day throughout the study period. The milk samples were taken to determine chemical composition of milk (fat, protein, total solid, solid not fat and milk density).

Statistical analysis
The collected data were analyzed with General Linear Model (GLM) procedure of SAS (2004) for least square analysis of variance. Mean comparisons were done using Duncan's Multiple Range Test (DMRT) for variables whose F-values declared a significant difference. Differences were considered statistically significant at 0.01% significance level.

Chemical composition of experimental feed
The percent feed chemical composition varied depending on feed type, in which the contents of CP, was higher in urea molasses block and concentrate mix ( Table 2). Urea-treatment increased CP content of the teff straw more than double from 3.2 to 7.83% and decrease NDF from 41.85 to 37.13% denoting the breakage of lignified bond and release of hemicellulose. Similar changes were observed in CP and NDF of wheat straw following urea treatment [6]. But, the CP content of treated straw observed in this study was lower than that of previous report of Rehrahie [3]. The effectiveness of urea treatment has been reported to be dependent on many factors among which the poorer the quality of the roughage the better is the response to urea treatment [7].

Agricultural Research & Technology: Open Access Journal
In the present study, at environmental temperature of mean minimum 13 ℃ and maximum 25 ℃, treated teff straw had pH value of 9 and appeared dark yellowish in color having soft consistency with modest ammonia smell ensuring the effectiveness of the treatment.

Daily nutrient intake of the experimental animals
Significant differences (P<0.01) were observed between treatments in daily nutrients intake. The total DM intake was improved in T2 as a result of UMB feeding as supplementary feed. Similar result was also reported in Fogera district where, supplementation of UMB increases DMI of cross-bred dairy cows [4].
Feeding urea treated teff straw was found to improve straw DM intake (10.18±0.08), compared to untreated teff straw (10.1±0.1kg per day). This result is in agreement with the finding of Teshome [8] who reported an increased DMI of cross-bred dairy cows fed urea treated wheat straw in Fogera district (Table 3).

Body weight gain
Significantly higher (P<0.01) daily weight gain was recorded in T1 compared to T2 and T3. T2 had higher daily weight gain compared to T3 (Table 4). In contrast, weight loss in lactating cross-bred dairy cows fed on treated rice straw was reported in Fogera District [8]. However, Takeba [4] reported that, the estimated daily body weight gain of cross-bred dairy cow supplemented with urea molasses block in Fogera district was 236g while others nonsupplemented cross-bred lactating cows 120g per day (Table 4).

Daily milk yield and composition
The main purpose of dairying in urban and peri-urban area of Lume district was to produce milk for marketing and family use. The area has market oriented dairy farms and hence the farmers kept cross-bred dairy cows and give priority for raw milk sale to cooperatives or to private milk traders.
There was significant difference (P<0.01) where the cows supplemented with UMB recorded higher daily milk yield (Table  5). Morning and evening milk yield was high in T2 (6.44±0.06 and 3.63±0.04); and followed by T1 (6.22±0.06 and 3.61±0.05) and T3 (5.46 ±0.07 and 3.24±0.04), respectively. Daily milk yield were 10.06±0.10, 9.61±0.09 and 8.70±0.11 in T2, T1 and T3 respectively. This finding is in agreement with Takeba [4] who reported that the saleable milk off-take of cows received the UMB supplementation was significantly increased by 34 % for crossbred dairy cows in Fogera District of Amahara region. But the result obtained in this study is much higher than that of Nkya et al. [9], who reported the average daily milk yield of crossbred dairy cows managed with cut and carry + UMB supplementation as 7kg per day at peri-urban areas of Tanzania. However, some finding shows higher milk yield than the milk yield obtained in this study. For instance, Seyoum & Fekede [10] reported the average daily milk yield of cross-bred dairy cows managed under cut and carry + UMB as 10.62kg per day at Holetta Agricultural Research Center (Table 5).

Conclusion and Recommendation
The improvement in feed and nutrient intake and the concomitant increase in the daily milk yield have different economic implications for the farmers in different livestock production systems. For instance, the greater improvement in daily milk yield of crossbred dairy cows in market oriented, periurban livestock production systems, where milk marketing is very attractive, will result in a significant economic advantage as compared to rural production systems, where milk has to be frequently converted into butter because of lacking market access. Therefore, use of urea molasses block for dairy animals will be effective in urban and peri urban area where milk market access is available.
In this study urea molasses block raise DM intake of roughages and milk yield where its production procedure is very easy and simple, can be produced from locally available materials and requires less labor. Therefore, commercial and smallholder dairy farmers can improve milk production as well as body weight of the milking cows through supplementation of UMB.
The overall least square mean of protein, fat, total solids, density and solids-not-fat (SNF) contents were not significantly different in the study area. But, Takeba [4] reported that, UMB supplementation significantly increased the milk fat content by 7 % in cross-bred dairy cows. However, Rehrahie [5] reported that only milk protein was significantly different while milk fat and total solid were not significantly different treated and untreated wheat straw. In addition, Rehrahie & Ledin [11] reported that the effect of hay-based diet, urea treated teff straw based diet and urea treated barley straw-based diet on milk fat percent didn't differed significantly.

Partial budget analysis of urea molasses block and urea treated teff straw
Based on average milk price paid to producers by milk cooperatives and private consumers, with 10.50 Birr/1t milk, cows fed UMB based diet have got the highest net return 83.27ETB /cow/day. This was followed by urea treated teff straw supplemented diet and control. Relatively, the better economic return of crossbred cows fed urea treated straw was reported by Rehrahie [5]. Takeba [4] also reported that, UMB supplementation seems to be economically meaningful for crossbred dairy cows only (Table 6).