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In vitro techniques used for evaluating ruminant feeds can be classified into those that estimate gravimetrically their digestibility or degradability by quantifying the insoluble residues that remain after their incubation in inoculum containing rumen fluid, and those that measure the appearance of fermentation products such as gases. This paper reviews the development of three important in vitro techniques and addresses some problems associated with them. It is argued that whereas in vitro gas techniques have received much attention over the last two decades on account of the ease with which gas production kinetics can be assessed, there is little hard evidence of their superiority over gravimetric techniques. A conceptual problem with in vitro gas measurements arises from the variation in the proportion of products of microbial degradation of feeds, i.e. short chain fatty acids (SCFA), microbial biomass and gases. It is demonstrated that a close stoichiometrical relationship exists between SCFA and gas production, and that both products can practically be considered as one fermentative complex. A potentially competitive relationship exists between this complex and microbial growth with respect to substrate utilization. This problem can be overcome by measuring true substrate degradability concomitantly with gas production. On this account, this paper advances the hypothesis that it is possible to select feeds with high degradability in the rumen and less gas released in relation to the amount of substrate degraded, which has direct implications as a means for improving the efficiency of utilization of feeds for meat and milk production, while decreasing the emissions of gases to the atmosphere.

An attempt was made to develop feasible processing methods for detoxification of undecorticated cottonseed meal (CSM) so as to incorporate it safely in rations of livestock and poultry. The processing methods were cooking at 100oC for 30, 45 and 60 min; pressure cooking at 5, 10 and 15 min; calcium hydroxide Ca (OH)2 treatment in concentrations of 0.5, 1.0 and 2.0% (w/w) and iron treatment in ratio of 1 part free gossypol (FG) to 0.2, 0.3 and 0.4 parts iron. The raw CSM contained 2700 ppm FG and 5183 ppm total gossypol. The FG content was lowered (P<0.01) by 30 min. cooking and then with 45 min. cooking, but a further increase in cooking time (60 min) did not reduce the FG content. A linear reduction (P<0.01) of FG was observed as the time of pressure-cooking increased. Treatment with 0.5, 1.0 and 2.0% Ca (OH)2 resulted in reduction (P<0.01) of FG by 21.25, 28.15 and 40.52%, respectively. Treatment with iron in ratio of 1:0.2, 0.3 and 0.4 parts iron reduced (P<0.01) the FG content linearly by 7.8, 20 and 32% and increased the iron concentration of meal by 0.05, 0.81 and 0.108%, respectively. The crude protein content of meal was not affected due to processing. The result of this study suggested that 15min. pressure cooking and 2% Ca (OH)2 treatment of CSM significantly (P<0.01) reduced the FG content to lower (P<0.01) levels in comparison to other processing methods followed by iron treatment in ratio of 1:0.4.

A survey was conducted during rabi season (February-March) to study the feeding pattern and the mineral status of buffaloes of Panipat District of Haryana state. Accordingly, the data related to feeds and feeding, milk production and samples of feeds, fodders, blood, hair and milk were collected from 8 sites representing the whole district. Animals were mainly stall fed and confined within a limited area. Use of common salt and mineral mixture as supplement was not a common practice among farmers. Berseem was the major green fodder available and fed liberally alone or with mustard cake to dairy animals besides green oats and gulidanda, the common weed with wheat crop. Further, it was noticed that the farmers were reluctant to feed paddy straw though wheat straw was scarce. The biological samples (feeds, fodders, blood, hair and milk) collected during survey were analysed for calcium (Ca), phosphorus (P), zinc (Zn), manganese (Mn), copper (Cu) and iron (Fe). The Ca and P contents in feeds and fodders were within the normal range. Zn was found to be deficient in wheat straw, paddy straw, green oats, mustard cake and wheat flour, while, these feeds and fodders had more Fe than the specified level. Berseem was found to be fairly rich in Cu and Mn but just optimum in case of Zn. Data on mineral analysis indicated that 46, 38 and 14 % of buffaloes had serum Ca, P and Zn below their respective critical levels, respectively. Analysis of hair and milk indicated deficiency of Zn and Cu, but not of Mn and Fe. Survey revealed the animals of this district need dietary supplementation of Ca, P, Zn and Cu in general and more particularly during lean season when green fodders are not available.

Feasibility of strategic supplementation to the basal diet of wheat straw in lactating does (17) was ascertained in an on-farm trial. A group of does (7) received a moderate amount (19.8±3.51 g/kg W0.75) of wheat bran as a supplement (WBS) as per farmers' practice while another group of does (10) was given a balanced concentrate mixture (BCM) at a level of 22.4±1.82 g/kg W0.75 to supply at least 50% higher amount of crude protein/digestible crude protein as compared to WBS. The animals were given wheat straw ad libitum as the sole basal roughage along with restricted grazing for 2-3 hours irrespective of dietary supplement. Farmers kept the kids with their dams to allow free suckling of milk during the experiment conducted over a period of 75 days. Though milk production during first 45 days of lactation was significantly higher (893 ml/day) in does given BCM as compared to their counterparts given WBS (575 ml/day), dietary supplements did not exert any discernible impact on milk composition. Consequently, the kids (17) suckling does under BCM group attained significantly higher growth rate (g/d) and body weight at the close of experimental feeding as compared to kids (10) of does given WBS. The partial budget analysis of additional feed cost and additional return in the form of live weight gain in kids nursed by does receiving BCM supplement indicate a lucrative marginal rate of return of over 350 per cent. The farmers appreciated the positive beneficial effect of supplementation on general health of does and growth rate of kids but requirement of assured cash out lays for quality feeds was perceived as the possible constraint in adoption of feeding BCM to does.

An experiment was conducted to assess the mineral status of vital organs of sheep fed different levels of minerals. Eighteen lambs, divided into three groups of six each, were fed gram straw and conventional concentrate mixture to meet their energy and protein requirements. One group (T1) received supplementation of mineral salts as per NRC requirement, while two other groups received 125% (T2) and 150% (T3) of minerals viz. calcium, phosphorus, sulphur, zinc and manganese as specified by NRC. However, the effective intakes of supplemented minerals were 100, 110 and 125% respectively. After feeding trial of 120 days, these lambs were slaughtered; vital organs (heart, liver, kidney and spleen) were collected and analyzed for Ca, P, S, Zn, Mn, Cu and Fe contents. An increase (P<0.05) in Zn and Mn contents and decreased in Cu content was observed in heart, muscle and liver with the graded supplementation levels. In kidney, the concentration of Cu, Mn and S increased due to feeding higher levels of dietary minerals. Mn and P contents were higher (P<0.05) in spleen of lambs fed higher levels of minerals. The concentration of Ca was less (P<0.05) in heart muscle, while it was more (P<0.05) in liver, kidney and spleen of sheep received higher minerals. The results indicated that vital organs especially liver and kidney responded markedly to the dietary concentration of minerals and hence could be used as indices to study mineral status of grazing lambs.

An on-farm study of 105 days duration was conducted on 14 local male goats (3-4 months old; 8.64 ± 0.54 kg BW) to demonstrate the beneficial effects of concentrate supplementation on growth performance of grazing animals to the farmers. Goats, divided into 2 groups (G1 and G2) of 7 each, were allowed to graze on rangeland for a period of 8 h/ day. Animals of G1 group received no supplementary feed, while animals of G2 group were given a concentrate mixture (consisted of barley, mustard cake, wheat bran, mineral mixture and common salt; 40: 30: 27: 2: 1) @ 1.0 % of their body weight. The mouth grab samples of pasture contained 11.1% CP and 42.2% ADF. Average daily gain was 17.6 and 39.4 g in G1 and G2 groups, respectively and the variation between the groups was significant (P< 0.01). The additional income due to additional inputs (Rs. 435.47) in G2 as compared to G1 was Rs. 651. Providing concentrate supplement @ 1.0% of the body weight to grazing goats appears to be profitable under field conditions.

In vitro studies were conducted to determine the effect of supplementation of finger millet straw (FMS) with different concentrate ingredients on NDF digestibility. The in vitro NDF digestibility of FMS which initially was 41.39 was enhanced (P<0.05) to 48.77±0.36, 47.79±0.19 and 48.91±0.16 with deoiled rice bran; 44.27±0.13, 48.90±0.01 and 47.22±0.20 with maize gluten meal -60; 46.44±0.16, 46.14±0.39 and 46.62±0.14 with groundnut cake; 45.24±0.33, 45.61±0.01 and 46.24±0.11 with cotton seed extractions and 42.68±0.16, 43.24±0.01 and 43.17±0.12 with copra cake depending on the level of dietary rumen degradable nitrogen (RDN). There was no significant difference in NDF digestibility due to different levels of RDN for these ingredients except in case of maize gluten meal-60 and maize gluten meal-40 where the NDF digestibility was significantly (P<0.05) higher at 22 and 30 g RDN/kg DOM for maize gluten meal-60 and 30g RDN/kg DOM for maize gluten meal -40. The mean NDF digestibility values were significantly (P<0.05) higher when supplemented with deoiled rice bran followed by maize gluten meal-60, groundnut cake, cotton seed extractions and copra cake. However, the mean digestibility values were not significantly (P<0.05) different between groundnut cake and cotton seed extractions. Supplementation with sunflower cake, safflower extractions and wheat bran significantly reduced the in vitro NDF digestibility of finger millet straw.

Fresh Flacourtia indica leaves (T1) as well as 48h wilted (T2) were fed as sole feed to eight Barbari goats randomly distributed into equal groups of 4 each. The leaves contained (on DM basis) crude protein 15, NDF 51.92, ADF 50.62, cell content 48.08, lignin 10.14, cellulose 40.23, silica 0.25, ether extract 2.05, total ash 7.21, calcium 1.34 and phosphorus 0.28 per cent. The leaves were low in anti-nutritional factors as exhibited by 24.2 mg/g catechin equivalent of tannin, 28.5 mg/g catechin equivalent of total phenols and 30.2 mg/g tannin equivalent of total phenol tannic acid. DM intake and digestibility coefficients of nutrients viz. DM, CP, NDF, ADF, CF, OM, NFE and EE were similar in both the groups. Though TDN intake (g/d) was significantly higher (P<0.05) in T2 (232.13±5.12) than T1 (202.44±11.21), no significant difference was evident in per cent TDN intake/kg BW. DCP intake was similar in both the groups. Serum protein, albumin, globulin, glucose, urea levels and creatine kinase activity were within the normal physiological range. Fresh or wilted F. indica leaves were found to be equally palatable and nutritious to goats without any apparent deleterious effect on the general health.

A feeding trial of 23 weeks (19 to 42 weeks of age) duration was conducted on one hundred laying birds randomly allotted to four dietary treatments. Treatment T1 was standard layer mash containing di-calcium phosphate (DCP) as the phosphorus source, while treatments T2, T3 and T4 consisted of di-ammonium phosphate (DAP) instead of DCP at 33, 66 and 100 per cent (w/w) levels, respectively, in mineral mixture. Feed intake did not differ significantly (P<0.05) among different groups except in T3 where it was significantly lower only in comparison to T1. While feed efficiency was significantly (P<0.05) lower in birds allotted T1 and T2 diets, the per cent hen day egg production was significantly higher in birds assigned T1 and T2 diets. However, the egg weight of birds allotted T1 diet was significantly higher than other groups. Among egg quality traits, albumin index, yolk index, shell thickness and shell weights were not influenced significantly (P>0.05) due to dietary treatments. The shape index was reduced due to inclusion of higher level of DAP and was significantly lower in birds allotted T4 diet. The haugh unit improved with increasing level of DAP and was maximum in birds assigned 100 per cent DAP diet (T4). It may be concluded that DAP can be incorporated safely up to 33 per cent level in place of DCP in the mineral mixture of layers.