Nutritional and socio-economic implications of feeding cereal straws supplemented with higher dietary level of de-oiled cakes to lactating buffaloes (Bubalus bubalis): an on-farm study

K Sharma, N Dutta and U Naulia

Centre for Advanced Studies in Animal Nutrition, Indian Veterinary Research Institute, Izatnagar-243 122, India
pn@ivri.up.nic.in

Abstract

Lactating buffaloes (35) were randomly selected to receive enhanced level of oil cakes (ES) in the concentrate (Parts/100: soybean meal/mustard cake 20/30, wheat bran 80/70). Fifteen buffaloes were given a concentrate mixture usually formulated by the farmer (Parts/100: mustard cake 8: wheat bran 92) and designated as control. The basal diet of cereal (wheat/paddy) straws was offered ad libitum while the amount of supplements was adjusted in consultation with the farmers during 10 months of feeding trial.

Total dry matter intake was similar in lactating buffaloes given control or ES supplement. The digestibility coefficient of various nutrients did not differ significantly (p<0.05) between both the treatments. However, the nutrient concentration of composite diet in terms of digestible crude protein (DCP) and total digestible nutrients (TDN) was significantly (p<0.05) higher in ES group as a consequence of higher level of protein. The intake (g/kg BW^o.75) of digestible organic matter, TDN and DCP was also significantly (p<0.05) higher in the buffaloes given ES supplement. The average milk production (kg/d) was comparable irrespective of dietary supplement up to first 60 days of lactation. A significant improvement in daily milk production was evident from 61 days onwards in buffaloes given ES supplement. Each buffalo in control and ES produced 1114+29.7 and 1488+30.1 litres milk, respectively during 300 d of lactation. However, the milk composition did not differ significantly in buffaloes fed either control or ES supplement. The percent marginal rates of return calculated over additional feed cost at different stages of lactation in buffaloes fed ES were 180, 591, 224, 232 and 156 during 0-60, 61-120, 181-240 and 240-300 days of lactation, respectively.

In the opinion of the participating farmers, though enhancement of cake in the concentrate brings overall improvement in the milk yield, body condition of animals and level of cash benefits, requirement of assured cash out lays may be a possible constraint in adoption of this strategy.

Key words: de-oiled cake, lactating buffaloes, nutrient utilization, supplementation, wheat straw

Introduction

In sharp contrast to the industrially advanced nations of the world, livestock production is a major component of the agricultural economy of developing countries like India and goes well beyond direct food production. They are closely linked to the social and cultural lives of millions of resource poor farmers for whom animal ownership ensures varying degrees of sustainable farming and economic stability. The synergies in crop-livestock systems provide opportunities for generating more income from the resources available. However, ruminant production in mixed farming has lagged behind in productivity because of factors like low genetic potential, poor health management and imbalanced feeding (Kiran Singh et al 1997). Nutrition remains by far the most critical constraint to increased animal productivity and more efficient performance across the developing countries (ILRI 1995) with the perpetual gap between the demand and supply of digestible crude protein (DCP) and total digestible nutrients (TDN); the former being the most critical at about 55 percent (Kiran Singh et al 1997). With the deterioration of natural rangelands due to overgrazing (Jodha 1986), and the tendency to divert better feeds (brans and cakes) to cities for use on specialized peri-urban dairy (Kiran Singh et al 1997), crop residues are assuming a prominent place in small holder ruminant production systems.

The major limitations with crop residues include their bulkiness and poor nutritive value. With the various enrichment (treatment) technologies available to improve the nutritive value finding little acceptance by farmers (Owen and Jayasuriya 1989; Dolberg 1992; Devendra 1997), the only viable option left is to concentrate on strategic supplementation with other feeds that provide additional protein, minerals and energy. Of the several alternative supplementation strategies that may be adopted, the most common is the use of purchased protein supplements, such as oil cakes (Devendra 1997). However, the choice of oil cake by resource poor farmers is usually driven by two factors, viz. availability and cost. Most of the farmers being small holders, only a few venture to buy supplements when money is available. Their access to commercially available feeds is quite restricted for financial and logistical reasons. Consequently, a small number of farmers use oilseed milling by-products produced and cultivated locally viz. mustard cake and groundnut cake to feed their dairy animals, mainly involving rearing of buffaloes. In recent years, farmers are being motivated to undertake cultivation of oilseeds to accelerate societal efforts towards self-sufficiency in edible oils and reduced dependence on imports.

Considerable research has gone into identifying and assessing the various possibilities of strategic supplementation, and there is no dearth of on-station feeding trials to evaluate nutritive value and animal response (Devendra 1997). However, the need for on-farm testing and demonstration far outweighs the need for further documentation of the effects of pre-treatments and supplementation (Doyle et al 1986). More research is required in on-farm feeding trials involving the physiological and other effects of supplementing fibrous feeds (Steinbach 1997). The present on-farm trial was therefore undertaken to demonstrate the potential efficacy of routine supplementation of oilcakes at a level higher than commonly being practiced by the farmers for better bioconversion of cereal straws, milk production and income generation while taking account of the prevalent feeding system, available resources and participating farmers' response.

Materials and Methods

Experimental site

The location chosen for the on-farm investigation, the Bareilly district of Uttar Pradesh province, is located at 170 m above sea level (28^O22^' latitude north and 79^O22^' longitude east) in the upper Gangetic Plain of northern India, having an annual rainfall of 900-1200 mm. It is the region of the deepest soil, with hardly any variation in relief. This constitutes the wheat and rice bowls of India and is fertile and suitable for growing various types of subtropical crops. Wheat and rice being the main cultivated crops, cereal straws form the basal diet of ruminants. Milk production in the area is characterized by low yielding non-descript buffaloes, small producers with little land holdings, use of crop residues with or without costly concentrates as feed supplements and scarce land for forage production.

Animals and diet

A 300-day lactation trial was conducted on 50 non-descript buffaloes collectively owned by 40 farmers in the study area. The initial selection of farmers was based on their willingness to participate and ownership of at least one lactating buffalo from 25 to 45 days post-partum producing a minimum of 4.0 litres milk per day. A group of lactating buffaloes (35) was  randomly selected and offered enhanced percentage of deoiled cakes (ES) in the concentrate (deoiled soybean meal 20, wheat bran 80 or mustard cake 30, wheat bran 70); another group of buffaloes (15) designated as control was given a concentrate mixture usually formulated by the farmer (mustard cake 6 or 8: wheat bran 92 or 94). Soybean meal was used only for short periods intermittently to the farmers (supplied from the project) to ensure continuity of feeding cakes throughout the trial, and during the digestion trial.  The basal diet of cereal (wheat/paddy) straw was offered ad libitum. The amount of ES or control supplements was given individually to each animal @ 1 kg supplement /21iters milk production and adjusted fortnightly as per change in milk yield in consultation with the farmers. Mineral mixture and salt were provided to all the buffaloes irrespective of dietary treatment. The on-farm feeding trial continued for about 10 months (300 d of lactation) during which measurement of length and heart girth were made at 30 days interval to estimate changes in live weight. Weekly records of milk production, dry matter intake (DMI) and general health of the animal were maintained; milk composition was monitored at fortnightly intervals throughout the experimental period. Records were kept by the researchers of the amount and type of supplement/basal feed offered to each buffalo in consultation with farmers by preparing pre-weighed packets of daily allowances. The information on various parameters of the study was collected during biweekly visits to the households of buffalo owners. The nutrient digestibility was measured by restricting the normal movements of the animals with the help of owners during the digestion trial. Farmers' perceptions, net benefit and marginal rate of return were also recorded at regular intervals.

Sampling and analysis

The lactating buffaloes were fed by farmers in individual feeding stalls during the entire experimental period and provided free access to water twice daily. A digestibility trial of 7 days was conducted following 60 days experimental feeding. Total dry matter intake and faecal out put (24 h) were recorded daily and a sub-sample collected and dried in a forced draught oven to a constant weight for dry matter estimation. Representative samples of each daily faecal collection were drawn, pooled for seven days and preserved in diluted (25%) sulphuric acid for N-estimation. The other samples were retained for further chemical analysis.

The pooled feed, residue and faeces samples, collected daily during the digestion trial were analysed for proximate composition (AOAC 1995) and fibre fractions (Goering and Van Soest 1970). Milk samples collected at fortnightly intervals were analysed for fat, total solids, SNF, crude protein and ash (ISI 1961). The economic analysis for marginal rate of returns (MRR) was undertaken as per procedures described by Stemmer et al (1998). The results obtained were subjected to analysis of variance, and treatment means were compared using t-test (Snedecor and Cochran 1989).

Results and Discussion

Chemical composition of feeds

The chemical composition of wheat straw and supplements (control and ES) is given in Table 1. The CP content of wheat straw was below the critical level required for normal forage consumption by buffaloes (NRC 1981; Kearl 1982). The increased level of cake in the ES group contributed to the improvement in overall CP content of the supplement and reduction in cell wall (NDF/ADF). However, the total ash and ether extract content in both the concentrates was comparable.

Nutrient intake and utilization

The pattern of nutrient intake, digestibility and plane of nutrition of lactating buffaloes given control or ES is depicted in Table 2 .

Though the DMI (% BW or g/kg W^0.75)  was comparable in buffaloes given control or ES supplement, the animals given ES tended to consume more straw as compared to their control counterparts.  The DMI of lactating buffaloes was reported as from 98.9 to 148 g/kg W^0.75 (Taparia and Sharma 1980; Lamba et al 2002). In this study, the buffaloes maintained a DM intake of 108-118 g/kg W^0.75 that clearly indicates high palatability of both the supplements to meet the DM requirement of experimental animals. Further, the intake of the concentrate moiety of the diet did not differ significantly in buffaloes irrespective of dietary supplement (Table 2). The digestibility coefficient of DM, OM, CP, EE, NDF and ADF did not differ significantly between both the treatments. Present results are in agreement with the earlier reports indicating that the digestibility of various nutrients in buffaloes did not differ significantly when 15-30 % additional nutrients are given in the form of nitrogen and energy (Chauhan et al 1997, 2000). The nutrient concentration and intake in term of DCP and TDN were significantly higher in ES group as a consequence of higher dietary level of cake (protein). However, it may be significant to note that DCP intake (g/day) of the lactating buffaloes even in ES group was about 20-25 per cent lower than the recommended value (730-770 g). The deficit in the intake of DCP by buffaloes given the control supplement was 42-45 percent which resulted in reduced milk yield and body condition. Similarly, the TDN intake, g/animal as well as per cent live weight or g/kg W^0.75 of buffaloes, in control or ES was lower by 7-18 and 18-28 per cent, respectively, to the recommended values (Kearl 1982; ICAR 1998). However, the animals in ES group could maintain the body condition and milk yield during the experiment which gives an indication that indigenous buffaloes may require moderately lower levels of dietary protein or TDN than the recommended values in vogue.

Milk yield and composition

The pattern of milk production during various phases of lactation is depicted in Figure 1.

The average daily milk production of buffaloes (kg/day) was comparable irrespective of dietary supplements up to first 60 days of lactation. This was understandable as it included 25-45 days pre-experimental period immediately after the calving in which farmers fed their own formulations. Besides, lactating animals also tend to mobilize their body reserves during the early stages of lactation to maintain the milk production. A definite improvement in the daily milk yield was evident from 61 days onwards in buffaloes given ES supplement. It was observed that each buffalo in Control and ES produced on an average 1114±29.8 and 1448±30.1 litres milk during 300 days of lactation. It is thus apparent that response of additional cake supplement was more obvious in increasing milk yield than digestibility of nutrients and a significant improvement in milk production of buffaloes (~335 litres) may be achieved during the lactation. Increasing protein supply during early lactation has been reported to significantly improve milk yield as it positively affects milk protein synthesis and milk volume (Roffler et al 1986; Chauhan et al 2000). However, the additional dietary protein or meal did not affect total solids, SNF, fat, crude protein and ash percentage of milk in conformity with earlier reports (Patle and Mudgal 1976; Paterson et al 1999; Chauhan et al 2000).

Socio-economic implications

The cost-benefit analysis of milk production system with enhanced supplementation of cake was examined in comparison to the traditional system with marginal amount of cake (Table 3). The additional costs of ES compared to control were the costs of additional straw and supplementary feed. The additional returns were in the form of sale of milk.

The additional cost involved due to higher level of cake in the diet gave a per cent marginal rate of return (MRR) of 180, 591, 224, 232 and 156 during the days 0-60, 61-120, 121-180, 181-240 and 241-300 of lactation, respectively. The effect of higher dietary level of cake was most pronounced during 61-120 days of lactation period. The overall MRR% of the lactation worked out to be around 273 in ES group which appears to be quite substantial in comparison to observed rate of return of 197% over feed cost in control. In view of fluctuating prices of milk and/ or feed ingredients, the MRR may also change. An increase in milk prices or a decrease in feed cost may increase the MRR and allure the farmers for maintaining the higher dietary level of cakes in the concentrate. Significantly, the overall cost of production of milk (Rs/lit) was lower (4.5) in buffaloes in ES group as compared to buffaloes in control (5.0). However, the cost of concentrate for lactating buffaloes could be reduced significantly if wheat bran is replaced by cheaper alternatives like rice polish. Even under existing feeding system, the higher level of cake in the ration could bring about an additional yield of 335 litres (equivalent to Rs. 3350) plus an extra income of Rs. 600.00 by reduction in cost of milk production. Thus, the milk producer could add up to Rs.13.0 /d or Rs.390.00 month on feeding of a buffalo giving about 5 lits milk/day. Consequently, the overall return (%)from investment in ES and control feeds (roughage/concentrate) given to buffaloes was 221 and 197, respectively.

Farmers' Perceptions

In the opinion of the participating farmers, the enhancement of cake in the concentrate brings overall improvement in the milk yield, body condition of animals and level of cash benefits. However, they felt that more assured cash out lays are necessary for purchase of feed ingredient like cake in ES group, which may be a constraint in the adoption of this practice.

Conclusions

• Lactating buffaloes fed basal diet of poor quality cereal straw required an increased supply of protein in concentrate supplement (22% CP) to ensure better milk yield and economic returns.
   
• In the opinion of farmers, the effect of oil cake supplementation was more apparent in the increased milk yield hence marginal rate of return, and in maintaining body condition for the lactating buffaloes.

Acknowledgement

This study was financially supported by funds provides by the Indian Council of Agriculture Research (AP-Cessfund), New Delhi, India

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