Availability of feed and fodder, both in quantitative and qualitative terms, is one of the major constraints in sustainable development of the livestock sector. It is well recognized that effective utilization of crop residues as animal feed is an alternative to overcome feed shortages for ruminant feeding (Rangnekar, 2003). Poor palatability and low bulk density apart from low nutritive value are restricting the utilization of the crop residues as animal feeds. Since the mid 1980′s there has been much research and development into finding ways of alleviating these short comings (Sundstol and Owen, 1984; Doyle et al., 1986). Incorporation of crop residues as a roughage source in complete diets (total mixed rations) of ruminants and their further densification is one of the practical ways of their utilization. Pelleting of low grade roughage based feeds improves uniformity, increases density, facilitates ease of handling and reduces wastage (Stevens, 1981). Similarly, physical form of the diet can affect potential rate of consumption with pelletized diets ingested more rapidly than the ones in mash form (Fahey et al., 1993; Berger et al., 1994). Though the argument on ill effect of goat rearing on ecology is a debatable issue, it is widely felt that unrestricted movement of goats should be prevented and goats with high production potential, which are capable of responding to quality feed, should be reared under confinement. Red gram (pigeon pea, Cajanus cajan) is a major pulse crop grown in Telangana region of Andhra Pradesh state in India. The straw that remains after harvesting the crop is regarded as wasteful product and is generally burnt out in the fields. Though red gram straw like many other agro industrial by-products is not palatable to animals in its original form, the nutrients present in the straw can potentially be made available to animals after applying suitable processing methods (Salem and Smith, 2008). Few efforts have been made to utilize red gram straw in the diets of different ruminant species (Narayanaswamy et al., 1990; Reddy, 1997; Suresha et al., 2006). An attempt has been made in the present study to utilize red gram straw (RGS) by incorporating into complete diets and feeding to goats in the form of mash or expander extruder processed pellets to assess growth and nutrient utilization under stall fed conditions.

On dry basis, red gram straw contained 9.26% crude protein (CP), 42.44% CF, 1.24% EE, 8.42% ash, 1.06% calcium and 0.23% phosphorus. The average daily feed intake during growth period was significantly (p<0.001) higher on pelleted diets while the effect of level of RGS in the diets on intake was non significant (Table 2). Goats consumed an average of 671.45 and 426.28 g feed on pelleted and mash diets respectively irrespective of level of RGS. The intake was 552.38 and 545.36 g/animal/d on feeds containing 35 and 50% RGS respectively irrespective of method of processing. Total weight gain and average daily gain (ADG) in kids were also significantly (p<0.001) influenced by feed processing while the effect of level of inclusion of RGS was non significant on growth rate. Goats on pelleted feeds gained an average of 10.69 kg in 150 d with an ADG of 71.29 g whereas those on mash feed gained only 48.79 g per day irrespective of level of RGS. The total weight gain (kg) and ADG (g) on feeds with 35% RGS were 9.48 and 63.17 while those on feeds with 50% RGS were 8.54 and 56.92 respectively. Apparent digestibility of nutrients was similar among mash and pelleted feeds (Table 2). Increasing the RGS in feeds decreased the digestibility of dry matter (DM), CP and CF resulting in lower (p<0.001) ME content in feeds containing 50% RGS. Though nutritive value of feeds was not affected due to pelleting, the average daily intake of DM, CP, digestible crude protein (DCP) and metabolizable energy (ME) per unit metabolic body weight were significantly (p<0.01) higher in pelleted diets. The Feed conversion efficiency (DMI:wt gain) was comparable among all the treatment groups.

Red gram straw used in the present study contained slightly lower CP and EE and higher CF and total ash contents when compared to the reports of Raut et al. (2002) and Rekhate et al. (2007) whereas, Kishore et al. (1997) reported slightly lower CP and CF and higher EE and total ash contents in red gram straw. Varietal differences among red gram crops might be the reason for this variation in proximate composition of straw. During the preparation of pellets, the procedure of reconstitution with water was followed instead of directly adding steam to the feed while passing through the screw to simplify the procedure for small scale production with minimal power consumption under field conditions wherein it may not always be possible to maintain boilers for steam generation (Valadez, 2008). The significantly (p<0.001) higher feed intake on pelleted diets might be due to the soft, pliable and cooked nature of expander extruded pellets together with natural disinclination of goats towards fineness of feed. The increase in intake due to pelleting of complete diets was in agreement with the reports of Singhal and Mudgal (1983), Reddy and Reddy (1991a) and Reddy et al. (1992). Hale and Theurer (1972) opined that pelleting of feeds increases acceptability by animals. Pi et al. (2005) reported higher feed intake in goats due to pelletization of complete diets. Gipson et al. (2007) offered alfalfa based complete feeds in pelleted as well as mash forms under stall feeding to meat goats and found significantly higher DM intake on pelleted diets. Similar total roughage level rather than the level of RGS in the diets might be the reason for similarity in intake between complete diets containing 35% and 50% RGS. The average daily gain observed in kids on mash feed was comparable with the reports of Murthy et al. (1995) who observed an ADG of 44.6 g and Chandrasekharaiah et al. (1996) who reported an ADG of 44.7 to 53.4 g when feed was offered in mash form. The higher weight gains on pelleted feeds were in agreement with the findings of Raut et al. (2002) wherein an ADG of 75 g was reported when complete diets containing 60% roughage were offered in pelleted form. The similarity in digestibility of nutrients between pelleted and mash diets was in contrast to the reports of Singhal and Mudgal (1983) who reported slight decrease and Reddy and Reddy (1991b) who reported an increase in digestibility of nutrients due to pelletization of complete diets. The decrease (p<0.05) in digestibility of DM and CP in diets containing 50% RGS was in agreement with the findings of Reddy and Raghavan (1987) and Reddy and Reddy (1984) who also reported a decrease in the digestibility of these nutrients due to an increase of roughage and fiber contents in feeds. The similarity in feed conversion efficiency (DMI: wt gain) among all the treatment groups indicated that the higher weight gain attained on pelleted dies was due to higher feed intake rather than higher nutritive value.

Expander extruder pelleting of complete diets significantly increased the voluntary feed intake and weight gain in goats and enabled effective utilization of red gram straw up to 50% level in complete diets.