Indian Journal of Dairy Science, 66(2): 113-119 (2013)

Effect of Feeding Balanced Ration on Milk Production, Enteric Methane Emission and Metabolic Profile in Crossbred Cows under Field Conditions

M R Garg1, P L Sherasia2*, B T Phondba3, S K Shelke4 and C T Patel5  

Animal Nutrition Group,

National Dairy Development Board,

Anand 388 001, Gujarat, India

 

A field study on early lactating crossbred cows (n=25) was conducted to evaluate the effect of feeding balanced ration on milk production, enteric methane emission and metabolic profile. Nutritional status of animals was analyzed by using ration balancing software package and microbial protein synthesis was calculated by estimation of urinary purine derivatives. Baseline methane emission of cows was measured using sulfur hexafluoride tracer technique, thereafter the ration was balanced as per their nutrient requirements. After 30 days of feeding a balanced ration, the methane emission was measured again. Analysis of feeding trial revealed that the dietary intakes of protein, energy and calcium were higher by 18.1, 8.0 and 19.5%, respectively whereas, phosphorus intake was lower by 9.0% in cows than their requirement. On feeding a balanced ration, milk yield, fat and 4% FCM yield were unaffected. Balancing of ration reduced enteric methane emission in terms of g/d and g/kg milk yield by 10.1 (P<0.01) and 13.5% (P<0.05), respectively, which further reduced the part of dietary gross energy loss as methane by 10.3% (P<0.01). Intestinal flow of microbial nitrogen increased by 51.4 g/d (P<0.01), whereas, faecal nitrogen excretion reduced by 19.4% (P<0.01) on feeding a balanced ration. Lower faecal parasitic egg count (43.8%; P<0.01) and improved levels of plasma immunoglobulins IgG (38.0%; P<0.01) and IgM (35.9%; P<0.05) were also recorded. Results of the study indicated that a balanced ration has the potential for improving microbial protein synthesis along with reducing enteric methane emission and faecal nitrogen excretion in lactating cows under field conditions.

Keywords: Balanced Ration, Milk Production, Enteric Methane Emission, Metabolic Profile, Crossbred Cows

                                                                     

Present address: 1General Manager, 2Scientist II, 3Scientist I, Animal Nutrition Group, NDDB, Anand-388001, Gujarat; 4Livestock Development Officer, Department of Animal Husbandry and Fisheries, Government of Maharashtra; 5Asst. Technical Executive, Banaskantha District Co-operative Milk Producers' Union Ltd., Banas Dairy, Palanpur, Gujarat.

INTRODUCTION

The Indian dairy sector acquired substantial growth momentum during the last three decades and achieved an annual output of 127.9 million tonnes of milk during 2011-12 (DADF, 2012). In spite, the average daily milk production data of various categories of animals at 6.52 kg for crossbreds, 2.10 kg for indigenous cattle and 4.44 kg for buffaloes (BAHS, 2007) suggests that the productivity of animals is far below than their genetic potential which could be attributed mainly due to deficiency of critical nutrients in the diet of animals. Milch animals in India are usually fed one or two locally available concentrate feed ingredients, grasses and crop residues. This often leads to feeding of an imbalanced ration, which contains proteins, energy, minerals and vitamins either in excess or deficient related to the nutrient requirements of the animals. Imbalanced feeding adversely impacts not only productivity, health and welfare of animals, but also the environment.

Ruminant livestock contribute up to 74% of the total methane emission from agriculture sector in India (INCCA, 2010). Over a wide range of diets, enteric methane accounts for 2 to 12% loss of dietary gross energy intake (Johnson and Johnson, 1995). Manipulating diet composition to induce changes in rumen fermentation characteristics remains the most feasible approach to achieve reduction in methane emission (Bayat and Shingfield, 2012). Various pilot studies conducted in different agro-climatic regions of the country revealed that it is possible to increase the productivity and reduce the cost of milk production through balanced feeding in an environmentally sustainable manner (Garg et al. 2013). In view of this, present study was planned under field conditions and the results are reported herein.

 

MATERIALS AND METHODS

Experimental Design

Twenty five early lactating (60-80 d post partum) crossbred cows were chosen for the study from three different villages of Banaskantha district in Gujarat state. The selected cows were in their third lactation, with an average milk production of 13.30 kg per day and 3.87% milk fat. The feed intake of individual animal was measured and representative samples were taken for proximate principles. Thereafter, the ration of all animals was balanced for total digestible nutrients (TDN), crude protein (CP), calcium and phosphorus using the ration balancing (RB) software developed by the National Dairy Development Board of India, which is based on National Research Council (2001) standards for cattle. The balanced diet was fed to all the cows for 30 days.

 

Laboratory Analysis

Feeds and fodder samples were analyzed for proximate composition as per AOAC (2005). The milk samples were analyzed for milk fat. Gross energy of feed and fodder samples was calculated as per the conversion factors of Jarrige (1989). The body weights of the animals were calculated using Shaeffers’s formula as: Body weight (kg) = ([(heart girth in inches)2 x length of the body in inches]/300) x 0.4536. Urine (100 ml) samples were collected from individual cow before and after feeding a balanced ration and were assayed for allantoin, uric acid and creatinine (Young and Conway, 1942). The PD excretion was based on the fact that excretion of creatinine is constant throughout a day therefore; creatinine was used as an internal marker for estimation of purine derivatives (Chen et al. 1992). In our study, the daily excretion of creatinine was considered as 0.98 mmol/kg W0.75 (Makkar, 2004). Purines absorbed and microbial nitrogen supply was calculated from the daily urinary PD excreted (IAEA, 1997). Fresh faecal samples from individual cow were collected for four consecutive days before and after feeding a balanced ration and pooled samples were analysed for nitrogen content (IS, 2005). The McMaster technique was used to quantify the parasitic eggs. Blood plasma was analyzed for immunoglobulins such as IgG, IgM and IgA, using kit supplied by DiaSys Diagnostic Systems GmbH (Holzheim, Germany) and blood urea nitrogen (BUN) concentration was estimated using the method described by Rahmatullah and Boyde (1980).

 

Enteric Methane Emission Measurement

Methane emission measurement was done by sulfur hexafluoride (SF6) tracer technique. The breath samples of all experimental animals were collected daily for four consecutive days in canisters and brought to the laboratory for methane and SF6 analyses at the start of study. After one month of feeding balanced ration, the methane emission was measured similarly. Methane and SF6 concentrations were determined by gas chromatograph (GC) instrument. All the samples were analysed in triplicate using GC, fitted with a molecular sieve 5A column for SF6 and a Porapack N for CH4. The column temperature was maintained at 50ºC and nitrogen was used as a carrier gas, with flow rate of 30 ml/min. Standards (Scott-Marrin Inc., Riverside, CA, USA) were used to standardize the GC for SF6 (39.2 pptv and 101.7 pptv) and CH4 (10.4 ppmv and 101.9 ppmv). Methane emission rate was calculated as: QCH4 = QSF6 x (CH4) / (SF6), where, QCH4 = Methane emission rate (g/min); QSF6 = Known release rate of SF6 from permeation tube (g/min); CH4 = Methane concentration of collected sample in canister (µg/m3); and SF6 = SF6 concentration of collected sample in canister (µg/m3). The data were statistically analysed using paired student’s t-test as per Snedecor and Cochran (1994).

 

RESULTS AND DISCUSSION

Feeding Practices and Ration Balancing

Feeding practices revealed that feeding of compound feed to dairy animals was common by the farmers in the district. Majority of the farmers used bajra and barley grains as energy source and cottonseed cake, guar korma and isabgol (Plantago ovata) as protein source for feeding milch animals. Lucerne, oat, hybrid napier and mixed local grasses were used as green fodder whereas, straws of bajra, groundnut, jowar and wheat were used as dry roughage. Feeding of area specific mineral mixture enriched with copper and phosphorus was practiced by the farmers of Banaskantha district. The chemical composition of feed and fodders offered during trial is presented in Table 1. Analysis of feeding practices revealed that the intake of protein, energy and calcium was higher by 18.1, 8.0 and 19.5%, respectively. The intake of phosphorus was lower by 9.0% than the requirement of animals, which is similar to the earlier reports of phosphorus deficiency in cows and buffaloes under field conditions of Gujarat (Kannan and Garg, 2009). After collection of the breath samples for baseline methane emission, the ration was balanced as per the requirement of individual animal for CP, TDN, Ca and P. Body weight and metabolic body weight were not affected (Table 2) by feeding a balanced ration to cows. After feeding a balanced ration to cows, the intakes of DM, CP and TDN were numerically lower and was mainly due to the restriction on intakes of these nutrients which otherwise were fed in excess by the farmers before feeding a balanced ration.  

 

Milk Yield, its Composition and Cost of Milk Production

In present study, milk yield, fat and 4% FCM yield in lactating cows were unaffected (P>0.05) on feeding a balanced ration. Balancing the ration as per nutrient requirement of cows helped to reduce the cost of feeding by 5.60% (Table 2). These findings are in accordance with Mohini and Singh (2010) who reported no change in milk yield and milk composition of cows after feeding a balanced ration along with urea molasses mineral block. Contrary to the present findings, animals fed on balanced ration showed improvement in milk production by 2-14% and its milk fat proportion by 0.2-15% in different parts of India (Garg et al. 2013).

 

Microbial Protein Supply

Microbial protein supply to the duodenum is an important indicator of efficiency of rumen function. Urinary excretion of allantoin has been successfully used to estimate microbial protein synthesized in the rumen and subsequently digested in the lower gut of ruminant. Urinary concentration of allantoin was improved after feeding a balanced ration to cows (12.53 vs. 16.23 mmol/l; P<0.01). Concentration of uric acid and creatinine in urine was not affected (P>0.05) by feeding a balanced ration. Balancing the ration of lactating cows resulted in significant improvement in PD concentration, PD index, PD excreted and absorbed purines thus, improved intestinal microbial nitrogen supply by 39.27% (P<0.01) in cows (Table 2). These findings are in consistent with the earlier report of Garg et al. (2012), wherein microbial nitrogen supply was improved by 39.35% on feeding a balanced ration in lactating buffaloes. In present study, an imbalance of protein, energy and minerals before RB might be responsible for poor availability of ATP and carbon skeleton for microbial cell production thereby reducing microbial protein synthesis. After balancing the ration of cows, the proper balance of nutrients might have resulted in higher microbial protein yield thereby, improving the performance of cows. A number of studies (Makkar and Chen, 2004) show that supply of adequate nutrients increases excretion of urinary purine derivatives, synthesis of rumen microbial protein and enhances the supply of protein post-ruminally to support production.   

 

Enteric Methane Emission

Baseline methane emission from cows averaged 211.48 g/d which reduced significantly by 10.10% (P<0.01) after feeding a balanced ration (190.11 g/d; Table 3). Methane emission per unit of milk yield was also reduced by 13.45% (P<0.05) after feeding a balanced ration to cows (15.90 vs. 13.76 g/kg milk yield). Similar to the present findings, Mohini and Singh (2010) reported lower methane emission (197.46 vs. 223.45 g/d and 29.92 vs. 40.04 g/kg milk yield) after balancing the ration of cows. Kannan and Garg (2009) also reported 10 to 15% reduction in methane emission after feeding a balanced ration to cows.

Feeding a balanced ration significantly reduced GE loss as methane from cows (2.82 vs. 2.53 Mcal/d; P<0.01; Table 3). Present results indicated that, cows fed on imbalanced plane of nutrition lost greater proportion of GE as methane (8.81 vs. 8.26%) and is consistent with the earlier reports in which GE loss as methane was higher (9.15 vs. 7.09%) in underfed cows than cows fed as per nutritional requirements (Mohini and Singh, 2010). Changing plane of nutrition through balanced nutrient approach improved nutrient digestibility and thus decreased methane production in lactating cows.  A greater efficiency of microbial protein synthesis and higher proportion of propionate relative to acetate, reduce digestive carbon losses through methane. An inverse relationship between microbial protein production, and its efficiency of production, with methane emissions have been reported (Waghorn and Hegarty, 2011). In present study, balancing of nutrients shifted the rumen fermentation pattern towards higher microbial cell production, which might have resulted in lower VFAs (acetate and butyrate) production and thereby reduced methane emission similar to Kannan et al. (2011).

Faecal and Blood Parameters

On feeding a balanced ration, faecal nitrogen content reduced by 19.4% (P<0.01; Table 4) which could be due to slightly lower intake of CP after balancing the ration of cows. Ration balancing also helped to reduce the parasitic infestation (eggs/g of faeces) in cows by 43.8% (P<0.01). Increased availability of essential nutrients can be expected to improve host resistance to gastrointestinal nematodes provided that they are first limiting to immune functions (Houdijk, 2012). Animals fed on imbalanced diet are vulnerable to parasitic infestation due to lower host immunity and parasitic load in dairy animals affects growth, milk production and general health. Study indicated that, balanced nutrient approach through ration balancing programme ensured access of cows to the ration with proper amount of energy, protein and minerals, which helped to reduce the parasitic load similar to the earlier report (Garg et al. 2013).

In present study the CP and TDN intakes were excess before balancing the ration and the baseline BUN level was within the normal range. In this case, excess availability of TDN could be responsible for adequate utilisation of CP which intern regulated baseline BUN level within the normal range (Table 4) with limited microbial protein synthesis, similar to the findings of Blummel et al. (2010). On feeding balanced rations, the excessive intake of CP and TDN was restricted to the requirement of animals. Thus, the adequate availability of both these nutrients through balanced rations might have increased the microbial protein synthesis in rumen of these animals while maintaining the BUN level in the normal range, and is in accordance with earlier reports in cows by Kannan et al. (2011).

Feeding of balanced rations improved humoral immunity IgG (38.0%; P<0.01) and IgM (35.9%; P<0.05) of cows (Table 4). Balanced rations provide all the necessary nutrients and minerals required for the optimum functionality of numerous structural proteins, enzymes and cellular proteins (Nocek et al. 2006). Reduction in parasitic load might have increased availability of protein and minerals to the cows which further stimulated the immune cell metabolism and thus improved humoral immune status of cows through higher IgG and IgM production. Phosphorus is associated with stimulation of immune function by providing ATP to the immune cells (Jokinen et al. 2003). As the phosphorus deficiency was prevalent before RB, balancing the ration in present study might have stimulated the immune function of cows by providing ATP to the immune cells, similar to Kiersztejn et al. (1992). 

 

CONCLUSIONS

The results of present study demonstrate that, ration balancing has the potential for improving microbial protein synthesis along with reducing enteric methane emission and faecal nitrogen excretion. Large scale implementation of ration balancing programme in tropical countries would not only help in increasing milk production and reducing daily feeding cost, but would also help in curtailing livestock mediated pollutants such as methane in air and nitrogen in manure.

 

ACKNOWLEDGEMENTS

Financial assistance and facilities provided by the management of National Dairy Development Board, Anand, for undertaking this study, are gratefully acknowledged.

 

REFERENCES

AOAC. 2005. Official Methods of Analysis. 18th edn. Association of Official Analytical Chemists International, Gaithersburg, Maryland, USA.

BAHS. 2007. Basic Animal Husbandry Statistics. 2007. Ministry of Agriculture, Department of Animal Husbandry, Dairying and Fisheries, Government of India, New Delhi.

Bayat, A. and Shingfield, K.J. 2012. Overview of nutritional strategies to lower enteric methane emissions in ruminants. Maataloustieteen Päivät. pp. 1-7.

Blummel, M., Write, I.A. and Hegde, N.G. 2010. Climate change impacts on livestock production and adaptation strategies: A global scenario. National Symposium on Climate Change and Rainfed Agriculture. pp. 136-145. Feb. 18-20, 2010. CRIDA, Hyderabad, India.

Chen, X.B., Grubic, G., Orskov, E.R. and Osuji, P. 1992. Effect of feeding frequency on diurnal variation in plasma and urine purine derivatives in steers. Anim. Prod. 55, 185-191.

DADF. 2012. Department of Animal Husbandry, Dairying and Fisheries, Ministry of Agriculture, Government of India, TCD Minutes, New Delhi.

Garg, M.R., Kannan, A., Phondba, B.T., Shelke, S.K. and Sherasia, P.L. 2012. A study on the effect of ration balancing for improving milk production and reducing methane emission in lactating buffaloes under field conditions. Indian J. Dairy Sci., 65(3): 250-255.

Garg, M.R., Sherasia, P.L., Bhanderi, B.M., Phondba, B.T., Shelke, S.K. and Makkar, H.P.S. 2013. Effects of feeding nutritionally balanced rations on animal productivity, feed conversion efficiency, feed nitrogen use efficiency, rumen microbial protein supply, parasitic load, immunity and enteric methane emissions of milking animals under field conditions. Anim. Feed Sci. Technol., 179: 24-35.

Haldar, S. and Rai, S.N. 2003. Effects of energy and mineral supplementation on nutrient digestibility and efficiency of milk production in lactating goats. Indian J. Anim. Nutr., 20: 244-251.

Houdijk, J.G.M., 2012. Differential effects of protein and energy scarcity on resistance to nematode parasites. Small Rumin. Res., 103: 41-49.

IAEA. 1997. Estimation of rumen microbial protein production from purine derivatives in urine. IAEA-TECDOC-945, International Atomic Energy Agency, Vienna, Austria.

INCCA. 2010. India: Greenhouse Gas Emissions. 2007. Ministry of Environment and Forests, Government of India.

IS. 2005. Animal feeding stuffs - Determination of nitrogen content and calculation of crude protein content: Part 2 block digestion/steam distillation method, IS/ISO-5983-2, Bereau of Indian Standards. New Delhi, India.

Jarrige. 1989. Ruminant Nutrition: Recommended allowances and feed tables. Institute National de la Recherche Agronomique, Paris, France.

Johnson, K.A. and Johnson, D.E. 1995. Methane emissions from cattle. J. Anim. Sci., 73: 2483-2492.

Jokinen, E.I., Vielma, J., Aaltonen, T.M. and Koskela, J. 2003. The effect of dietary phosphorus deficiency on the immune responses of European white fish (Coregonus lavaretus L.). Fish Shellfish Immunol., 15: 159-168.

Kannan, A. and Garg, M.R. 2009. Effect of ration balancing on methane emission reduction in lactating animals under field conditions. Indian J. Dairy Sci., 62: 292-296.

Kannan, A., Garg, M.R. and Mahesh Kumar, B.V. 2011. Effect of ration balancing on milk production, microbial protein synthesis and methane emission in crossbred cows under field conditions in Chittoor district of Andhra Pradesh. Indian J. Anim. Nutr., 28: 117-132.

Kiersztejn, M.I., Chervu, M., Smogorzewski, G.Z., Fadda, J.M., Alexiewicz and Massry, S. G. 1992. On the mechanisms of impaired phagocytosis in phosphate depletion. J. American Soc. Nephrol., 2: 1484-1489.

Makkar, H.P.S.  2004. Development, standardization and validation of nuclear based technologies for estimating microbial protein supply in ruminant livestock for improving productivity, in: Makkar, H.P.S., Chen, X.B., Estimation of Microbial Protein Supply in Ruminants Using Urinary Purine Derivatives. FAO/IAEA, Kluwer Academic Publisher, p. 2-13.

Makkar, H.P.S. and Chen, X.B. 2004. Estimation of microbial protein supply in ruminants using urinary purine derivatives. IAEA-CN-110, Vienna, Austria.

Mohini, M. and Singh, G.P. 2010. Effect of supplementation of urea molasses mineral block (UMMB) on the milk yield and methane production in lactating cattle on different plane of nutrition. Indian J. Anim. Nutr., 27: 96-102.

Nocek, J.E., Socha, M.T. and Tomlinson, D.J. 2006. The effect of trace mineral fortification level and source on performance of dairy cattle. J. Dairy Sci., 89: 2679-2693.

NRC. 2001. Nutrient Requirements of Dairy Cattle. 7th Rev. Edn. National Research Council. National Academy Press. Washington, DC.

Rahmatullah, M. and Boyde, T.R.C. 1980. An improvement in determination of urea using diacetyl monoxine method with and without deproteinization. Clin. Chem. Acta., 107: 3-9.

Snedecor, G.W. and Cochran, W.G. 1994. Statistical Methods, 8th edn. Iowa State University Press, Ames, Iowa.

Waghorn, G.C., Hegarty, R.S. 2011. Lowering ruminant methane emissions through improved feed conversion efficiency. Anim. Feed Sci. Technol., 166-167, 291-301.

Young, E.G. and Conway, C.F. 1942. Estimation of allantoin by the Rimini-Schryver reaction. J. Biol. Chem., 142: 839-853.

 

Table 1: Chemical composition of feed and fodders (% DM basis)

 

Particulars	Crude protein	Ether extract	Crude fibre	Total ash	AIA	Ca	P
Concentrates
Compound feed	22.86	2.99	10.94	13.85	3.12	2.08	1.41
Bajra grain	11.54	3.41	1.85	4.72	1.87	0.09	0.38
Barley grain	12.40	2.15	5.48	2.47	0.18	0.04	0.47
Wheat grain	11.62	2.35	2.51	2.20	0.24	0.03	0.27
Black gram chunni	13.11	2.89	7.09	5.10	0.81	1.11	0.45
Cotton seed cake	26.92	8.65	20.44	4.83	0.16	0.17	0.82
Guar korma	38.08	4.85	6.09	5.39	0.56	0.39	0.55
Isabgol (Lali)	25.64	10.72	9.76	4.08	0.31	0.37	0.72
Isabgol (Jiraru)	18.47	2.68	27.62	1.74	0.40	0.18	0.30
Soybean flakes	14.88	3.83	30.35	4.64	0.85	0.51	0.18
Maize bhardo	9.02	2.99	1.14	1.40	0.14	0.04	0.29
Wheat bhardo	11.08	1.93	1.72	2.11	2.83	0.04	0.36
Roughages
Chicory leaves	22.93	3.46	14.39	25.23	4.53	1.75	0.52
Lucerne fodder	23.66	5.4	19.48	10.04	0.93	2.24	0.36
Hybrid Napier	21.49	2.18	23.11	17.09	3.97	0.64	0.64
Oat fodder	10.13	1.37	25.80	11.87	7.39	0.52	0.17
Jowar fodder	8.46	0.48	26.55	7.15	4.23	0.57	0.22
Maize fodder	7.82	1.12	28.45	12.84	3.52	0.49	0.40
Local grasses	9.84	6.21	27.48	15.2	8.54	1.43	0.24
Neem leaves	15.41	5.41	16.49	8.13	0.76	2.23	0.18
Bajra straw	4.66	2.84	37.11	6.92	2.15	0.66	0.14
Groundnut straw	11.4	1.13	31.38	6.82	0.66	1.42	0.21
Guar straw	6.39	0.92	40.99	6.9	1.73	0.70	0.12
Jowar straw	4.31	0.55	27.54	5.7	2.14	0.47	0.28
Pulse straw	7.52	2.07	31.77	9.71	2.83	1.32	0.16
Wheat straw	2.89	1.36	37.96	8.27	5.96	0.14	0.05

 

Table 2: Effect of ration balancing (RB) on nutrient intake, milk production and microbial protein synthesis

Parameter	Before RB	After RB
Body weight (kg)	378.32 ± 9.24	385.88 ± 9.07
Metabolic body wt. (kg w0.75)	85.78 ± 6.55	87.06 ± 5.87
Nutrient intake
DM intake (kg/d)	14.50 ± 0.61	13.73 ± 0.42
DM intake (kg/100 kg body wt.)	3.83 ± 0.18	3.55 ± 0.11
CP intake (g/d)	1780.40 ± 12.54	1729.22 ± 13.43
TDN intake (kg/d)	8.01 ± 0.32	7.53 ± 0.21
Milk yield and its composition
Milk yield (kg/d)	13.30 ± 0.74	13.81 ± 0.57
4% FCM yield (kg/d)	13.06 ± 0.74	13.78 ± 0.60
Milk fat (%)	3.87 ± 0.07	3.98 ± 0.08
Cost of production (Rs./kg MY)	9.29 ± 0.32	8.77 ± 0.41
Microbial protein synthesis
Allantoin (mmol/l)	12.53a ± 0.66	16.23b ± 0.55
Uric acid (mmol/l)	1.33 ± 0.14	1.64 ± 0.10
Creatinine (mmol/l)	7.04 ± 0.57	6.76 ± 0.45
Purine derivatives concentration (mmol/l)	13.86a ± 0.64	17.87b ± 0.59
PDC index	168.87a ± 16.23	230.14b ± 22.68
Total PD excreted (mmol/d)	165.49a ± 15.91	225.53b ± 22.23
Absorbed purine (mmol/d)	179.85a ± 18.68	250.49b ± 26.20
Intestinal flow of microbial nitrogen (g/d)	130.75a ± 13.58	182.10b ± 19.05

a,b Values with different superscript in a row differ significantly (P<0.01).

 

 

Table 3: Effect of ration balancing (RB) on enteric methane emission

Parameter	Before RB	After RB
Methane emission (g/d)	211.48a ± 7.12	190.11b ± 8.52
Methane emission (g/kg milk yield)	15.90c ± 1.25	13.76d ± 0.78
DM intake (kg/d)	14.50 ± 0.61	13.73 ± 0.42
Methane emission (g/kg DM intake)	14.58 ± 0.99	13.84 ± 0.76
Organic matter intake (kg/d)	13.00 ± 0.63	12.26 ± 0.57
Methane emission (g/kg OM intake)	17.17 ± 0.82	15.85 ± 0.71
Gross energy intake (Mcal/d)	31.98 ± 0.62	30.62 ± 0.56
Energy loss as methane (Mcal/d)	2.82a ± 0.10	2.53b ± 0.11
Energy loss as methane (% of gross energy)	8.81 ± 0.41	8.26 ± 0.37

 

a,b Values with different superscript in a row differ significantly (P<0.01).

c,d Values with different superscript in a row differ significantly (P<0.05).

 

Table 4: Effect of ration balancing (RB) on feacal and blood parameters

Parameter	Before RB	After RB
Faecal parameters
Dry matter (%)	17.83 ± 0.66	19.02 ± 0.36
Organic matter (%)	81.33 ± 0.75	79.83 ± 0.56
Nitrogen (%)	1.80a ± 0.08	1.45b ± 0.03
Eggs per gram of faeces	153a ± 14.76	86b ± 6.35
Blood parameters
BUN (mg/dl)	11.68 ± 0.81	11.82 ± 0.84
Creatinine (mmol/l)	0.11 ± 0.01	0.12 ± 0.01
Uric acid (mmol/l)	0.04 ± 0.01	0.04 ± 0.01
IgG (mg/ml)	15.86a ± 1.16	21.90b ± 1.30
IgA (mg/ml)	0.25 ± 0.03	0.38 ± 0.05
IgM (mg/ml)	2.20c ± 0.28	2.99d ± 0.27

 

a,b Values with different superscript in a row differ significantly (P<0.01).

c,d Values with different superscript in a row differ significantly (P<0.05).