Performance Evaluation of Crossbred Cattle Fed Treated Leftover Feed

India being a tropical south Asian developing nation has a large deficit of cereal grains, dry and green fodder. At present there is a shortage of 11.24% green fodder, 23.4% dry crop residues and 28.9% concentrate feed ingredients (IGFRI-2020). This gap can be filled either by increasing crop productivity, utilizing untapped feed resources, increasing land area, or through imports. The bovine are the largest dairy animals which mainly subsist on green fodder followed by dry roughage and concentrate mixture. The feeding cost in dairy animals accounts for the highest input factor of the total cost of rearing and production (60-70%). The net cultivated area is around 142 million hectare in addition to forests and their associated grasslands and fodder sources (Singh et al., 2014). There is high pressure on land for crop production in order to meet the growing demands of food grains for human consumption and hence farmers cannot spare land for fodder production to feed the cattle (Singh et al., 2014; Singh et al., 2020a). At many organized farm in India, leftover feed constitute bulk roughage which is generally considered as waste material and discarded in crop-fields. The composition of leftover varies depending upon the fodder variety however by and large the leftover consist mainly of maize, jowar, bajra, berseem and napier grass in northern plain region of India (Birthal and Jha, 2005). It has been reported that if molasses and urea mixture is supplied to the animals with straw then intake, digestibility and palatability of feed increases (Sahoo et al., 2004; Verma et al., 2006). Various studies have been conducted for this purpose by treating the inferior quality feed with urea, ammonia and molasses with different inclusion levels which provided positive results. It was observed that urea treatment could increase nutritive value of straw by 46% (Wanapat et al., 2009) due to breakage of bonds between the lignin, hemi-cellulose and cellulose. The feeding practices using these feed have also improved the productivity of dairy animals (Singh et al., 2014). From the perusal of literature, it is found that the most of earlier research works have been targeted on treatment of dry crop residues (wheat straw or rice straw) using supplementation of urea as nitrogen or molasses as energy sources but no study has been conducted on treatment of the fresh leftover feed having high moisture contents (more than 50 per cent). The treatment of leftover feed using different combinations of urea, molasses and salt may enhance its nutritive value as well as its palatability. The treated leftover feed can also serve as better feed during the scarcity or lean period. It is also expected that feeding of these treated feed may reduce the feeding cost without affecting the performance of animals. 
 

Place of study
 
The study was conducted at Cattle and Buffalo Farm, ICAR-Indian Veterinary Research Institute, Izatnagar, India during 2018-19 which is located at latitude of 28^o 22' north, longitude of 79^o 24' East and altitude of 169.2 meter above the mean sea level. The location comes under upper gangetic plain region and has sub-tropical climatic condition with high humidity.
 
Design of experiment
 
The experiment was conducted in two phase’s viz. 1) Feasibility assessment of treated leftover feed and  2) Palatability and performance evaluation of dairy cattle using different combinations of treated leftover feed with fresh fodder. The leftover feed consisted of chaffed fodder sorghum, millets, maize, napier grass and berseem (clover) as raw material. Six combinations of urea, molasses and salt were used for treating the leftover feed (Table 1) to increase its nutritive value and palatability. The feasibility of the treatment during the months of December to April was tested and weight gain of animals in different treatment groups was compared.


 
Selection of experimental animals
 
A total of 24 crossbred cattle (8-12 months of age) were selected and randomly allocated to four different groups (6 animals per group) viz. Group-1 (Gr-1): 100% treated leftover feed; Group-2 (Gr-2): 75% treated feed; Group-3 (Gr-3): 50% treated feed and Group-4 (Gr-4) or Control: 100% green fodder, without use of treated feed. Feeding was done by providing each feed for one week subsequent to each other and one week was given between each treatment as adjustment period (Table 2).


       
Palatability score was used to test the palatability of the treatment; all the 24 animals were weighed before and after each feeding trail and their weight gains were compared after the end of each trial.
 
Chemical analysis of feed
 
Leftover feed was analysed before and after treatment to find out changes in the the chemical composition. The presence of fungal toxins viz. mycotoxin and ochratoxin were also tested in the treated feed. Testing was done using automatic chromatographic technique and methanol was used as solvent.
 
Feasibility testing
 
Leftover feed was mixed with urea, molasses and salt and packed in polybag of 25 kg capacity in airtight condition for incubation period of 21 days, thereafter polybags were opened and feed were valuated physically for smell, colour and texture. Moisture content was sufficient in the leftover feed so there was no requirement of water sprinkling.
 
Palatability testing
 
Palatability scores were given based on acceptance and time taken by animals to start feeding as mentioned in Table 3.


 
Performance of the animals
 
Performance of the animals was evaluated based on weight gain before and after each feeding trail.
 
Statistical analysis
 
The data obtained from the experiments were analysed using the SPSS 20.0 software package

The chemical composition of leftover feed before and after treatment with urea, molasses and salt has been presented in Table 4.


       
The treatment of leftover feed was feasible during the winter and spring months of the year. The nutritional quality of the leftover feed increased after each treatment and there were no traces of mycotoxin and ochratoxin in any of the treated feed. Crude protein content increased due to increased nitrogen content following urea treatment where as crude fibre content increased which might be due to break down of ester bonds between the lignin, hemi-cellulose and cellulose. Ash content increased because of addition of salt and other impurities.
 
Palatability of the feed
 
Palatability of the treated feed in different groups were measured by using palatability scored as mentioned in Table 5.


       
Palatability scores show identical trends in all the treatment groups. The high value of palatability score indicated that feed acceptability was poor in treatment than control. From the results as shown in Table 3, it is evident that animals fed on 100 percent fresh feed in Gr-4 had better acceptability whereas Gr-1 with 100 per cent treated leftover feed had the lowest acceptability. Among the treatments, the combinations of treated and fresh feed (in ratio of 50:50 and 75:25) gave better results in terms of feed acceptability without any adverse effect on performance of the growing animals (Table 2).
 
Performance of the animals
 
Performance of the experimental animals in terms of changes in their boy weights are shown in Table 6.


       
The difference of initial body weights (IW) was non-significant in all the groups. The final body (FW) and weight gain (WG) of animals for F3 and F5 were found significant in Gr-1 compared with control, however Gr-3 and Gr-4 were non-significant with control.  Among the proportion of treated and fresh feed, the weight gain in Gr-2 was found superior even than control, however the difference was non-significant. The equivalent performance in Gr-2 than control might be due increased nutritive values of feed and better acceptability than other groups. In 3rd and 5th group the initial body weight of animals in control, Gr-1, Gr-2 and Gr-3 was non-significant among each other. The final body of animals in different groups were also found non-significant. The weight gain was significantly (p<0.5) lower in Gr-1 where 100 percent treated feed was offered to animals than control, Gr-2 but non-significant from Gr-3. The equivalent performance in Gr-2 might be due increased nutritive values of feed along with acceptability and better palatability in control group.
 
Economics of the feed
 
Economic feasibility of the treated feed in different groups were measured by using scorecards as mentioned in Table 7.


       
Feeding cost chart shows that there was reduction in feeding cost up to almost half in 1^st  and 2^nd treatment groups feeding cost was somewhat higher in 3^rd treatment group due to higher cost of molasses but even though it was lower than the control group. Among the treatments, the combinations of treated and fresh feed (in ratio of 50:50 and 75:25) gave better results in terms of feed acceptability without any adverse effect on performance of the growing animals.
 
Chemical composition of feed
 
The nutritive value of the feed increased after every treatment which was due to urea ammoniation of leftover feed and increased content of carbohydrate, molasses, ash was due to minerals present in salt and other impurities present in premix. The increase in crude protein and crude fibre content is in agreement with Hamad et al. (2010) and Sarwar et al. (2010) who found higher crude protein and total protein content of barley or wheat straw being treated with 4% urea. Reduction of energy intake during far off period provided positive results in crossbred animals (Singh et al., 2020a; Singh et al., 2020b). Results are also in line with Oji et al(2007) who reported increase in crude protein content and crude fibre content of maize residues from 2.9 to 5.9% when treated with 3% urea and CP content increased to 6.7% when treated with 5% urea. Hassan et al. (2011) reported high ruminal NH3-N in bulls fed urea treated straw. Dutta et al. (2004) and Dass et al. (2000) reported increase in crude protein by urea ammoniation of wheat straw whereas higher digestible protein and digestible nutrients were recorded by Prasad et al. (1998) in rations containing either stacked or baled urea treated rice straw. Treatments fifth and sixth contained only molasses and salt and they had sweet smell and golden brown colour so their palatability was comparatively better. Sahoo et al. (2002) reported that organic matter, neutral detergent fibre and hemicellulose digestibility were highest in urea treated wheat straw. Similarly, many reports say that urea treated wheat straw increased the ruminal NH₃ concentration (Manyuchi et al., 1992; Nisa et al., 2004; Sarwar et al., 2004; Jabbar et al, 2008). Ramirez et al. (2007) reported decrease in acid detergent fibre on treatment of Zea mays with urea.
 
Performance of animals
 
Significant difference in weight gain of the animals in treatment groups for F3 and F5 feed where lower weight gain in Gr1 were observed which might be due less palatability of treated feed than that of fresh green fodder. The equivalent performance in Gr-2 might be due increased nutritive values of feed along with acceptability and better palatability (Garg et al., 2006). Kilic and Emre (2017) reported that digestibility of wheat and soybean straw could be improved upon some additives however in present study feed palatability was taken in account for performance evaluation along with weight gain. Mishra et al. (2012) found that supplementation of urea molasses block significantly increased the milk yield, live weight and body score of cows. Similarly, the enhanced acceptability of feed upon treatment with molasses was observed in crossbred heifers and lambs (Rath et al., 2001).
 
 

Treatment of left over feed using different combinations of urea, molasses and salt was feasible and increased nutritive values in terms of crude protein without production of fungal toxins. The animals fed on 50 per cent treated feed and 50 percent fresh green fodder had equivalent palatability and weight gain in comparison to control group. The leftover feed can efficiently be utilized for feeding to various classes of dairy animals under farm conditions to minimize the rearing cost and could also serve a better option during the scarcity period of fodder production. Body weight gains were not diminished when the treated feed is given even upto the levels of 75 per cent but it was not higher than the group fed with green fodder. 
 

The authors report no conflict of interest over the content of this paper.
 

The authors are thankful to the Director, ICAR-Indian Veterinary Research Institute (IVRI), Izatnagar for providing all the necessary facilities during the study.