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1 Italian Journal of Animal Science 2012; volume 11:e11 PAPER Effect of supplementation with protein differ for rumen degradability on milk production and nutrients utilization in early lactating Sahiwal cows Illahi B. Marghazani, 1 Makhdoon A. Jabbar, 1 Talat N. Pasha, 1 Muhammad Abdullah 2 1 Department of Food and Nutrition, University of Veterinary and Animal Sciences, Lahore, Pakistan 2 Department of Animal Production, University of Veterinary and Animal Sciences, Lahore, Pakistan Abstract Early lactating Sahiwal cows (n=24) of approximately similar yield and lactation were selected and randomly divided into four groups of six cows in each. These groups were fed ad libitum four iso- energetic and iso- proteic diets with different rumen undegradable protein (RUP) sources: diet A 30% RUP, diet B 40% RUP, diet C 50% RUP and diet D 60% RUP in a completely randomized design. Among nutrients intake, dry matter (DM) and crude protein (CP) intake was significantly (P<0.01) different, while neutral detergent fibre (NDF) and acid detergent fibre (ADF) intakes were similar across four diets. DM, CP and NDF digestibility were also different (P<0.05) except, NDF digestibility. Whole milk yield (kg/d) and 4% fat corrected milk (FCM) (kg/d), fat (g/d) and protein (g/d) was found maximum on diet B, followed by diet A. Not significant differences were found in fat, solid not fat (SNF), protein, lactose, salts and total solids percentage across all diet except SNF, lactose and salts percentages which were significantly lower (P<0.05) on diet D. Nitrogen intake, balance and utilization were statistically similar across all diets however, nitrogen excretion in milk (g/d and percentage of intake) and urine (percentage of intake) were significantly different across diets. Nitrogen intake and output varied (P<0.01) across all diets. Nitrogen balance and its utilization were maximum (P<0.001) on diet B, while other diets showed not significant differences among themselves. Based on presenting findings, it is concluded that feed intake, digestibility and production performance was maximum in early lactating Sahiwal cows when fed 40% rumen undegradable protein in total mixed ration based diet. Introduction Pakistan stands among the leading milk producing countries of the world. Nili-Ravi buffalo and Sahiwal cow are the major milk producing dairy animals of Pakistan. Cows are 35.6 million of heads and share 16,133 thousand tons to the total milk (46,440) produced in the country (Government of Pakistan, 2011). Although, it is far less than buffaloes, yet this share is constantly increasing since last few years. However, production per dairy animal in Pakistan is far less than recognized dairy cattle breeds of the world. Sahiwal cow is the major dairy cattle breed of Pakistan and has inherent specialties of heat and tick resistance. Despite of some promising qualities in Sahiwal cattle breed, scientific research in evaluating nutritional requirements to maximize yield is still deficient. In Pakistan, dairy animals are fed on rations based on conventional systems of energy and protein. This system does not consider the requirements of metabolizable protein need of early lactating and rapidly growing animals. The new concept of balancing crude protein for Rumen degradable protein (RDP) and rumen undegradable protein (RUP) is not known in Pakistan. The RDP is utilized for microbial growth while RUP remained inert in rumen and digested in small intestine form higher yield (Kamalak et al., 2005). It is reported that lactating and young growing animals fed on high RDP can not give its optimum performance due to high demand for RUP at that physiological status of animal (Habib, 2009). Kalscheur et al. (2006) also reported that ruminally undegradable protein needs to be supplement when microbial protein synthesis alone is insufficient to meet the metabolizable protein requirements in dairy animals especially during early lactation. When there is an increase in the dietary rumen undegradable protein milk yield increases (Gulati et al., 2005; Garg et al., 2007; Habib, 2009). Lack of response in milk yield, milk fat and protein on increasing RUP % in diets is also reported (Chritensen et al., 1993). The higher RDP than requirements of rumen microbes results in wastage of expensive part of diet and also decreases the RUP for efficient utilization in small intestine for more yields (Reynal and Broderick, 2003). Corresponding author: Dr. Illahi Bakhsh Marghazani, Department of Food and Nutrition, Faculty of Animal Production and Technology, University of Veterinary and Animal Sciences, Lahore, Pakistan. Tel Fax: marghazani76@yahoo.com Key words: Rumen undegradable protein, Nutrient digestibility, Milk composition. Received for publication: 19 September Revision received: 4 December Accepted for publication: 10 December This work is licensed under a Creative Commons Attribution NonCommercial 3.0 License (CC BY- NC 3.0). Copyright I.B. Marghazani et al., 2012 Licensee PAGEPress, Italy Italian Journal of Animal Science 2012; 11:e11 doi: /ijas.2012.e11 Most of the research studies on effect of protein supplements of varying degradability on performance and nutrients utilization have been conducted on high yielding lactating cows in the developed world on native feed resources. In Pakistan, the work on indigenous protein sources with different degradability levels on production performance particularly in early lactating Sahiwal cows is lacking. Hence, understanding the degradability levels of protein in the diet of indigenous dairy breed Sahiwal will assist in evaluating proper diet formulation strategy particularly during early lactation. This study, therefore, planned to know the effect of protein supplements of varying degradability on milk production and composition and nutrient utilization in early lactating Sahiwal cows. Materials and methods Study was carried out at the Government Livestock Farm, Kallurkot, Pakistan. Description of the work is given under. Twenty-four multiparous early lactating (17±08 days) Sahiwal cows were selected and randomly divided into four groups in a completely randomized design. Each group was of approximately similar milk yield and lactation. This experiment lasted for 105 days in which first fifteen days given to experimental animals for adaptation to their respective diets while, remaining period (90 days) used for data collection. All animals of each group were- [page 58] [Ital J Anim Sci vol.11:e11, 2012]

2 Ruminal P degradability in Sahiwal cows housed, tied and fed ad libitum in mangers having separate arrangement. Rations were offered daily at 9:00 am to their respective groups. Left feed was weighed, recorded and discarded before offering fresh weighed rations. Animals were milked twice a day at 2:00 am and 2:00 pm. Representative samples of feed offered, feed left and milk were taken daily and pooled for individual animals of each group. Total mixed ration (TMR) was prepared having protein of different rumen degradable and undegradable ratios (Table 1) for each group. In particular, rations A, B, C and D contained 30, 40, 50 and 60% (RUP) of total crude protein, respectively. Ration B served as control group having 60:40 (RDP:RUP) ratios as recommended for large dairy cattle breeds (NRC, 2001). All TMR were iso- caloric and isonitrogenous (NRC, 2001). For the preparation of rations 3 and 4, rapeseed meal was treated with formaldehyde solution (1 g formaldehyde/ 100 gram crude protein) as suggested in the findings of Faran and Pasha (2000). In ration- 4, corn gluten meal 60% was subjected to heat treatment for 1 h at 15 lb (Faran and Pasha, 2000) using automatic autoclave. Prior to commencement of feeding trial, all total mixed rations (A, B, C and D) were evaluated for rumen degradable and undegradable fraction through in situ technique (Cottrill and Evans, 1984) in two adult rumen fistulated Nili-Ravi buffalo steers. Dacron bags were incubated in the rumen for 3, 6, 12, 24 and 48 hours. Zero hour degradability was determined without ruminal incubation and the Dacron bags containing sample were rinsed with cold water in the same way as other bags that were removed from rumen (Woods et al., 2002; Kamalak et al., 2005). Data on crude protein degradability at different hours of rumen incubation were fitted to Orskov and McDonald (1979) equation. Data on feed intake (feed offered- feed refused) and milk production were recorded daily while milk composition on weekly basis. Fat, solid not fat (SNF), lactose, protein, salts and total solids percentages were determined with calibrated milk analyzer (EKOMILK, Milkana KAM 98-2A, Bulteh 2000 Ltd., Stara Zagora, Bulgaria). Data for live weight change was recorded in the morning before feeding for each animal at monthly intervals. During the last week of study a digestibility trial was conducted for five days duration using total collection method. Three cows from each group were randomly selected and total faeces, urine and milk of each animal were collected and recorded daily. For urine collection, cows were kept in individual partitions that had special arrangement for automatic flow in containers (acidified with 50% H2SO4) placed under pens. Each morning, the volume of urine was recorded, mixed and 20% sub-samples were taken and pooled for individual cow (Marghazani et al., 1999). Similarly, feed, faecal, and milk samples (20%) were pooled (- 20 C) separately for each cow. All collected samples were chemically analyzed to calculate dry matter (DM), crude protein (CP) (AOAC, 2000), neutral detergent fibre (NDF), acid detergent fibre (ADF) (Van Soest et al., 1991) digestibility, nitrogen balance and nitrogen utilization. Data thus obtained on nutrients intake and digestibility, milk yield and milk composition, nitrogen balance and utilization were statistically analyzed through analysis of variance technique under completely randomized design (Steel et al., 1997) using Statistical Analysis System (SAS, 1997). Means were compared for significance of difference with the Duncan s Multiple Range Test (Duncan, 1955). Mathematical model is given as under: Yij = μ + τ i + ε ij where: Y ij, each observation on i th treatment due to j th animal μ, overall mean τ i, effect of i th treatment ( τi = 0 and i = 1, 2, 3) ε ij, random error associated with i th treatment and j th animal with the restriction that variance σ 2 and mean zero. Results and discussion Nutrients intake and utilization Nutrients intake in Sahiwal cows fed rations varying in rumen degradability of protein (Table 2) showed significant differences in dry matter and crude protein intakes in these rations (P<0.01), whereas NDF and ADF intakes were statistically similar (P>0.05) in all diets. DM intake was maximum in diets B and A, while minimum in diets C and D. Although, DM intake in diets B and A was statistically similar (P>0.05), an increasing tendency was observed with increase in RUP from 30% (diet A) to 40% (diet B). However, this tendency decreased (P<0.01) with further increase in RUP proportion in other diets (C, 50% and D, 60%). Nevertheless, comparatively Table 1. Ingredients (%) and chemical composition of experimental total mixed rations fed to early lactating Sahiwal cows. Ration 1 Ration 2 Ration 3 Ration 4 Ingredients Wheat straw, % Wheat bran, % Molasses, % Rice polishing, % Broken maize, % CGM 60% CGM 60% (HT) Rapeseed meal, % Rapeseed meal (FT), % Sunflower meal, % Soybean meal, % Cotton seed cake, % Blood meal, % Urea, % Mineral mixture, % Chemical composition DM, % ME, Mcal/kg CP, % NDF, % ADF, % RUP (% CP) (kp=5%) RDP: RUP 69:31 61:39 50:50 39:61 CGM, corn gluten meal; HT, heat treated; FT, formaldehyde treated; DM, dry matter; ME, metabolizable energy; CP, crude protein; NDF, neutral detergent fibre; ADF, acid detergent fibre; RUP, rumen undegradable protein; RDP, rumen degradable protein. Mineral mixture composition: dicalcium phosphate, 708 g/kg; sodium choloride, 189 g/kg; magnesium sulphate, 86 g/kg; iron sulphate, 8.9 g/kg; manganese sulphate, 4.9 g/kg; zinc sulphate, 3.2 g/kg; copper sulphate, 0.3 g/kg; potassium iodide, mg/kg; cobalt chloride, mg/kg; sodium selenate, mg/kg. [Ital J Anim Sci vol.11:e11, 2012] [page 59]

3 Marghazani et al. higher dry matter intake on diets B and A suggests efficient rumen fermentation due to availability of proper proportion of rumen degradable protein for microbial need which may have resulted in increased DM intake. It is also assumed that rumen degradable part provides nitrogen in diversified form for microbial growth, which led to improved rumen environment and hence, increases feed intake (Delcurto et al., 1990). The influence of degradability nature of diets showed more pronounced tendency (P<0.01) in CP intake as diet B>A>C>D. This trend of CP intake is due to almost similar trend of DM intake on these respective diets. These results are partly according to Blackwelder et al. (1998) who reported increased CP intake due to increased DM intake. Further, level of protein degradability in different rations showed any influence (P>0.05) on NDF and ADF intakes in experimental groups. Significant differences were found in DM, CP and NDF digestibility, while ADF digestibility remained unaltered across all diets. DM digestibility increased (P<0.05) with increasing RUP proportion in diet, the highest value was found in 40% RUP diet which decreased with further increase in RUP% in diets (C and D). These results suggest that 60% RDP (B) in diets may have provided adequate ammonia N for microbial growth, which might have improved rumen fermentation and DM digestibility. Further increase in RDP level may decrease RUP percentage in small intestine, while any decrease in RDP level may influence microbial growth and DM digestibility. CP digestibility was also different among experimental diets (P<0.001). Although statistically similar, diet B (40% RUP) showed maximum CP digestibility compared with diet A (30% RUP), while further increase in RUP % in diets C and D decreased (P<0.001) CP digestibility. This last result suggest low availability of ammonia N for rumen microbes due to their increased RUP proportions which in turn may have resulted in reduced microbial synthesis and, hence, digestion. Earlier findings (Kowalczyk et al., 1993) also reported decreased CP digestibility with increased RUP% in diets. NDF digestibility showed similar tendency as diet B showed maximum (P<0.05) digestibility followed in diet A and minimum in diets C and D. The increased NDF digestibility on diet B suggests maximum and efficient microbial growth on these RDP and RUP proportions in early lactating Sahiwal cows. ADF digestibility remained the same across all the diets, which explains that different RUP proportion in experimental diets has no effect on ADF utilization. Winsryg et al. (1991) also reported similar effects on ADF digestibility using protein sources of different rumen degradability. Milk yield and composition Results showed that varying protein degradability in experimental diets had significant effects (P<0.001) on production performance of early lactating Sahiwal cows (Table 3). Yield trend in these diets are presented in Figure 1. Milk yield (kg/d) increased with increase in RUP proportion up to 40% (B), however it significantly declined with further increase in RUP to either 50% (C) or 60 % (D). It followed similar trend in 4% fat corrected milk (FCM), even if it, the 4% FCM yield was statistically similar to diets B and A. The higher milk yield on diet B and declining tendency on other diets was directly proportional to dry matter intake. It followed the general concept that maximizing DM intake (through better feeding strategy) in early lactating cows leads to higher peak yield. These results also explain that diet B (40% RUP, 60% RDP) not only provided adequate ammonia N for microbial synthesis but also fulfilled animal s amino acid requirement in intestine for enhanced milk yield. The lack of response on diets A, C and D partly explains the imbalance in RDP and RUP proportions in diets for the need of rumen microbes and availability in intestine for milk synthesis. Habib (2009) reported that increasing the levels of rumen degradable protein in diets of dairy animals does not always enhance milk yield due to limited supply of metabolizable protein. On the other hand, supplying more than adequate RUP proportion in diets limits carbohydrate digestion and VFA production, which in turn affects animal s production performance. Milk composition (i.e., fat, protein and total solids) was statistically similar in all diets. The solid not fat (SNF), lactose and salts contents Table 2. Mean (± SE) nutrients intake and utilization in early lactating Sahiwal cows fed rations varying in protein degradability. Intake DM, kg/d 12.65±0.25 a 12.78±0.37 a 11.68±0.28 b 11.28±0.44 b ** CP, kg/d 2.16±0.04 ab 2.20±0.07 a 2.01±0.05 bc 1.92±0.07 c ** NDF, kg/d 4.83± ± ± ±0.17 ns ADF, kg/d 2.82± ± ± ±0.10 ns Digestibility DM, % 58.53±1.56 ab 62.99±1.16 a 56.63±2.06 b 54.29±3.17 b * CP, % 61.01±1.72 a 66.39±1.33 a 53.48±2.71 b 53.05±2.31 b *** NDF, % 43.59±2.55 ab 47.35±2.08 a 37.07±2.88 b 36.52±3.77 b * ADF, % 34.33± ± ± ±3.37 ns Diet A, 30 % RUP; diet B, 40% RUP; diet C, 50% RUP; diet D, 60% RUP. NDF, neutral detergent fibre; ADF, acid detergent fibre; DM, dry matter; CP, crude protein; a-c means with different superscripts within same row are significantly different (P<0.05); *P<0.05; **P<0.01; ***P<0.001; ns, not significant (P>0.05). Table 3. Mean (± SE) milk yield and composition in early lactating Sahiwal cows fed rations varying in protein degradability. Milk yield Whole (as such), kg/d 8.82±0.058 b 9.25±0.062 a 8.49±0.052 c 8.15±0.058 d *** 4% FCM, kg/d 9.54±0.074 a 9.74±0.072 a 9.25±0.073 b 8.85±0.070 c *** Milk composition Fat, % 4.49± ± ± ±0.09 ns SNF, % 9.12±0.05 a 9.11±0.04 a 9.14±0.04 a 8.99±0.04 b * Protein, % 3.43± ± ± ±0.02 ns Lactose, % 5.02±0.03 a 5.01±0.03 a 5.03±0.02 a 4.95±0.02 b * Salts, % 0.76±0.00 a 0.76±0.00 a 0.76±0.00 a 0.75±0.00 b * Total solids 13.64± ± ± ±0.10 ns Components yield Fat, g/d ±3.60 a ±3.68 a ±3.60 b ±3.58 c *** Protein, g/d ±2.22 b ±2.25 a ±3.85 b ±2.16 c *** Diet A, 30% RUP; diet B, 40% RUP; diet C, 50% RUP; diet D, 60% RUP. FCM, fat corrected milk; SNF, solids not fat; a-d means with different superscripts within same row are significantly different (P<0.05); *P<0.05; ***P<0.001; ns, not significant (P>0.05). [page 60] [Ital J Anim Sci vol.11:e11, 2012]

4 Ruminal P degradability in Sahiwal cows were also similar among diets A, B and C, however, diet D showed significantly (P<0.05) lower value for these contents (Table 3). These results can explain inefficient production of rumen microbes in this diet, which in turn affected efficient digestion and absorption for milk synthesis. The lack of statistical difference in fat, protein and total solids with increase in RUP percentage in diets is in line with earlier studies: Balckwelder et al. (1998) observed any effect of RUP supplementation on milk composition. Similarly, Schroeder and Gagliostro (2001) reported non-significant differences in milk fat, protein and lactose percentage on RUP diets in early lactating cows. In milk components yield (g/d), fat and protein yields were significantly different (P<0.001). Protein yield was high on diet having the maximum milk yield (B) while it was lowest on diet having the lowest milk yield (D). Fat yield also followed the same pattern, however, due to comparatively higher fat percentage on diet A than B, produced statistically similar fat yield on both diets. Nitrogen balance Nitrogen intake, excretion, balance and utilization in early lactating Sahiwal cows fed rations varying in protein degradability are given in Table 4. Nitrogen intake was significantly different among different diets (P<0.01). However, the difference between diet B and A were not significant (P>0.05). The difference in nitrogen intake in early lactating Sahiwal cows is due to difference in dry matter intake, which followed similar trend. In nitrogen output, faecal excretion was statistically unaffected by RUP percentage in diets, however it was significantly affected as percent of N intake. It was highest (P<0.001) on maximum RUP percentage in diets, i.e. diet D, followed by diet C and lowest (P<0.001) on minimum RUP percentage in diets, i.e. A and B. Similarly to our findings, Lines and Weiss (1996) reported increase in faecal N output with increased RUP% in diets. These results of faecal out put also suggest the efficiency of RUP percentage in experimental diets, i.e. the more faecal N excretion, the less the efficiency of respective diets in terms of production and utilization. In urinary N output (g/d) significant differences (P<0.01) were observed in different experimental diets, however, as percent of N intake it was statistically similar (P>0.05). Urinary N excretion (g/d) was maximum (P<0.01) on low RUP diets (A and B), while lowest on high RUP percentage diets (C and D). These results suggest that diets with higher RUP percentage have a tendency towards lower N excretion. Accordingly, Figure 1. Milk yield trend in early lactating Sahiwal cows fed rations varying in protein degradability. Table 4. Mean (± SE) nitrogen intake, excretion, balance and utilization in early lactating Sahiwal cows fed rations varying in protein degradability. Nitrogen intake, g/d ±6.68 ab ±10.26 a ±7.57 bc ±11.85 c ** Nitrogen output, g/d Faecal ± ± ± ±11.13 ns Urinary ±6.16 a ±11.40 a ±9.66 b ±7.04 b ** Milk 38.09±1.26 ab 40.18±1.08 a 35.65±1.14 b 36.57±0.96 b * Nitrogen balance, g/d 28.87±3.75b 52.81±8.03 a 21.47±2.70 b 15.65±1.91 b *** Nitrogen output, % of intake Faecal 38.99±1.72 b 33.61±1.33 b 46.52±2.71 a 46.95±2.31 a *** Urinary 41.67± ± ± ±2.08 ns Milk 11.12± ± ± ±0.58 ns Nitrogen balance, % of intake 8.22±0.99 b 15.15±2.23 a 6.62 ±0.83 b 5.14 ±0.66 b *** Nitrogen utilization, % 19.34±0.95 b 26.71±2.33 a 17.84±2.33 b 17.29±0.82 b *** Diet A, 30% RUP; diet B, 40% RUP; diet C, 50% RUP; diet D, 60% RUP; Nitrogen balance: N intake N output (faecal N + urinary N a-c + milk N); means with different superscripts within same row are significantly different (P<0.05); *P<0.05; **P<0.01; ***P<0.001; ns, not significant (P>0.05). Castillo et al. (2001) found increased urinary N excretion on diets having more RDP. N excretion through milk as g/d was affected (P<0.05) by diets and was maximum on 40% RUP (diet B) followed by 30% RUP (diet A), while minimum on 50% and 60% RUP diets. This trend of milk N excretion is based on milk yield on different diets, i.e. diets yielded more milk caused more N to flow for the protein synthesis in milk. Nitrogen balance as g/d or percent of N intake was significantly (P<0.001) different on experimental diets. It followed the trend as diet B >A> C and D. These results suggest that N was more efficiently utilized on diet B (60% RDP: 40% RUP), which stimulated maximum microbial growth and flow of undegraded protein to intestine and caused minimum N excretion through faeces. Comparatively, low N balance on higher RUP diets (C and D) was due to maximum N excretion through faeces on these diets, which may be due to low microbial growth which consequently reduced digestibility. In N utilization, all diets performed statistically similar (P>0.05) except diet B, which may be due to high N balance on this diet, i.e. due to comparatively less faecal N excretion and almost similar milk N output. Conclusions Effect of protein supplements having different rumen degradability characteristics (30, 40, 50 and 60% RUP) influenced nutrients intake, digestibility and yield performance during early lactation in Sahiwal cows. DM intake, digestibility, milk yield, nitrogen balance and utilization was maximum in Diet B (40% RUP) however, diet A (30% RUP) produced similar influence in DM intake and digestibility. No improvement in yield observed with further increase in RUP percentage in diets. This study confirms the recommendations of NRC (2001) for RDP and RUP requirements of early lactating cows NRC (2001). [Ital J Anim Sci vol.11:e11, 2012] [page 61]

5 Marghazani et al. Studies on different lactation phases in native dairy cattle and buffaloes are fertile areas of further research. References AOAC, Official methods of analysis. 17th ed., Association of Official Analytical Chemists, Washington, DC, USA. Blackwelder, J.T., Hopkins, B.A., Diaz, D.E., Whitlow, L.W., Brownie, C., Milk production and plasma gossypol of cows fed cottonseed and oilseed meals with or without rumen-undegradable protein. J. Dairy Sci. 81: Castillo, A.R., Kebreab, E., Beever, D.E., Barbi, J.H., Sutton, J.D., Kirby, H.C., France, J., The effect of protein supplementation on nitrogen utilization in lactating dairy cows fed grass silage diets. J. Anim. Sci. 79: Christensen, R.A., Lynnch, G.L., Clark, J.H., Yu, Y., Influence of amount and degradability of protein on production of milk and milk components by lactating Holstein cows. J. Dairy Sci. 76: Cottrill, B.R., Evans, P.J., Estimation of protein degradability: A standard method for in sacco measurement of nitrogen measurement of nitrogen disappearance from Dacron bags suspended in the rumen. Agricultural Research Council Technical Review, Farnham Royal, Berks, UK. Delcurto, T., Cochran, R.C., Harmon, D.L., Beharka, A.A., Jacques, K.A., Towne, G., Vanzant. E.S., Supplementation of dormant tall grass-prairie forage: 1. influence of varying supplemental protein and (or) energy levels on forage utilization characteristics of beef steers in confinement. J. Anim. Sci. 68: Duncan, D.B., Multiple Range and Multiple F Tests. Biometrics 11:1-42. Faran, H., Pasha, T.N., Effect of varying levels of formaldehyde and heat treatment on in situ ruminal degradation of different vegetable protein meals. Int. J. Agr. Biol. 2: Garg, M.R., Sherasia, P.L., Bahanderi, B.M., Gulati, S.K., Scott, T.W., Milk production efficiency improvement in buffaloes through use of slow ammonia release and protected protein supplement. Ital. J. Anim. Sci. 6(Suppl.2): Government of Pakistan, Economic survey of Pakistan Economic Adviser Wing, Finance Division, Government of Pakistan Publ., Islamabad, Pakistan, pp Gulati, S.K., Garg, M.R., Scott, T.W., Rumen protected protein and fat produced from oil seeds and meals by formaldehyde treatment ; their role in ruminant production and product quality: a review. Aust. J. Exp. Agr. 45: Habib, G., Nutritional mangement strategies to improve milk production in buffaloes. Pakistan J. Zool. Suppl. Ser. 9: Kalscheur, K.F., Baldwin, R.L., Glenn, B.P., Kohn, R.A., Milk production of dairy cows fed differing concentrations of rumen degraded protein. J. Dairy Sci. 89: Kamalak, A., Canbolat, O., Gurbuz, Y., Ozay, O., Protected protein and amino acid in ruminants nutrition. KSU J. Sci. Engineering 8: Kowalczyk, J., Buczkowski, Z., Jaczawaka., A., Pawlus, U., Performance and wool growth in lambs fed rations containing formaldehyde treated protein. J. Anim. Feed Sci. 2: Lines, L.W., Weiss, P.W., Use of nitrogen from ammoniated alfalfa hay, urea, soybean meal and animal protein meal by lactating cows. J. Dairy Sci. 79: Marghazani, I.B., Habib, G., Siddiqui, M.M., Nitrogen retention and nutrients digestibility in sheep given a basal diet of Sorghum hay supplemented with protein of varying degradabilities. Sarhad J. Agric. 15: National Research Council, Nutrient requirements of dairy cattle. 7th rev. ed. National Academy Press, Washington, DC, USA. Orskov, E.R., McDonald, I., The estimation of protein degradability in the rumen from incubation measurements weighed according to rate of passage. J. agric. Sci. 92: Reynal, S.M., Broderick, G.A., Effects of feeding dairy cows protein supplements of varying ruminal degradability. J. Dairy Sci. 86: SAS, User s Guide. Ver SAS Inst. Inc., Cary, NC, USA. Schroeder, G.F., Gagliostro, G.A., Fish meal supplementation to grazing dairy cows in early lactation. J. Dairy Sci. 83: Steel, R.G.D, Torrie, J.H., Dickey, D.A., Principles and procedures of statistics. A biochemical approach. 3rd ed., McGraw Hill Co. Inc., New York, NY, USA. Van Soest, P.J., Robertson, J.B., Lewis, B.A., Methods of dietary fiber, neutral detergent fiber and nonstarch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74: Winsryg, M.D., Arambel, M.J., Walters, J.L., The effect of protein degradability on milk composition and production of early lactation, somatotropic injected cows. J. Dairy Sci. 74: Woods, V.B., Moloney, A.P., O Mara, F.P., The effect of level of feeding and grass silage to concentrate ratio on the in situ degradability of concentrate ingredients in steers. Anim. Feed Sci. Tech. 100: [page 62] [Ital J Anim Sci vol.11:e11, 2012]