Effect of Feeding Solid Multi-Nutrient Blocks on Feed Intake, Nutrient Utilization and Haemato-Biochemical Profile of Crossbred Calves

In India livestock mainly subsist on poor quality feeds and fodder that are deficient in energy, protein, mineral and vitamin. As a result, performance of animal is often sub-optimal that is reflected in stunted growth, delayed maturity, longer inter-calving period and poor milk yield. Dietary supplementation of critical nutrients can improve the utilization of poor quality roughages. Considering the availability and price of concentrate mixture, resource poor farmers can hardly afford them. One of the main focuses of animal nutrition research in this country is to improve nutritive value of cereal straws through strategic supplements that are cheaper as compared to grains and oilseed meals. Use of NPN substances like urea was tried to replace the costly source of proteins in ruminant diet. Supplementation of urea molasses mineral block (UMMB) showed promising results in improving the nutrient utilization and the productivity of animals (Sihag et al., 2007; Wadhwani et al., 2010). This offers several advantages such as easy transport, storage and handling and reduced risks of poisoning as compared with other approaches, such as giving a small amount of urea in drinking water, sprinkling of urea solution on fibrous feeds before feeding, or urea-ammonization of crop residues (Dutta et al., 2009). These advantages of solid multi-nutrient blocks (SMB) opened up new vista to enhance productivity in terms of increased milk and meat production and higher reproductive efficiency in ruminant animal species. Keeping the above facts in view, this study was undertaken to determine the effect of feeding solid multinutrient blocks on feed intake, nutrient utilization and haemato-biochemical profile of crossbred calves.

Twenty four healthy crossbred growing calves of about 14 to 17 months of age and mean body weight (BW) of 195±2.0 kg were selected. All the animals were ear tagged and housed in separate sheds having provision of both open and close space at Animal Nutrition Shed, ICAR-Indian Veterinary Research Institute, Izatnagar. Prior to the experimental feeding, all animals were dewormed with albendazole @ 5 mg/kg BW. Clean and fresh drinking water was made available throughout the experimental period. Animals were randomly divided into four groups of 6 each by using completely randomization design and fed as per Ranjhan (1998) to meet the maintenance and growth requirement for a period of 150 days. All animals were supplied wheat straw ad lib. In addition, animals in all groups were fed a conventional concentrate mixture (maize 43; wheat bran 42, deoiled soy bean 12, mineral mixture 02 and common salt 01%) to meet out their nutrient requirement. Additionally, 30% of concentrate mixture (on CP basis) was replaced by solid multinutrient blocks-I (SMBI), SMB-II and SMB-III in groups T₁, T₂ and T₃, respectively. The SMB varied in physical composition (Table 1). The representative samples of SMB, concentrate mixture and wheat straw offered and left over were collected daily and dried in hot air oven to a constant weight for DM estimation. During 6 days metabolism trial, daily samples of feeds and faeces were collected and oven dried whereas the aliquots of fresh faeces and urine were preserved in 10% H₂SO₄. These samples were analysed for proximate principles (AOAC, 1995) and cell wall fractions (Van Soest et al., 1991). Blood samples were collected from all the animals at 0, 75 and 150 day interval in each group by jugular vein puncture with proper antiseptic precautions. Serum was harvested and stored at-20°C until use. Plasma samples were analyzed for hemoglobin (Dacie and Lewis, 1969) and packed cell volume (Jain, 1986). Serum samples were assayed for glucose, total protein (Doumas, 1975) and albumin (Gustaffson, 1978), globulin was determined as the difference between total protein and albumin concentration in the plasma. The ratio between albumin and globulin was calculated as A:G ratio. Serum concentration of urea, creatinine and calcium was determined using commercial kits. Serum concentration of phosphorus was measured according to Miller et al., (1994). The activity of alanine amino transferase (ALT) and aspartate amino transferase was determined using standard methods (Reitman and Frankel, 1957). The experimental data generated were analyzed using statistical package SPSS 11.0 adopting standard statistical procedures (Snedecor and Cochran, 1994). Significance was declared at p<0.05 unless otherwise stated.
 

Effect of feeding solid multinutrient blocks on feed intake, digestibility and nutrient utilization
 
Chemical composition of different feeds and solid multinutrient blocks has been presented in Table 1. The plane of nutrition of animals has been shown in Table 2. Our results revealed that the voluntary dry matter intake and digestibility did not vary significantly among the four groups. Our results of dry matter intake are not in concurrence with the observation of some other researchers (Muralidharan et al., 2016; Hassen and Ali, 2019). The dry matter intake (DMI) and organic matter intake (OMI) were comparable (p>0.05) among the all groups. This indicates that there was no effect of feeding SMB on the palatability and acceptability of diet. Several factors like breed, age, season, quality of feed, physiological state, etc. influence feed consumption in ruminants. In this experiment, all the animals were of similar age, body weight and, were maintained under uniform environmental conditions and were fed diets having a similar energy density. The sudden introduction of urea into the diet was sometimes associated with palatability problems (Koster et al., 1997). However, in this experiment urea molasses mineral blocks were introduced gradually over a period of 10 days that allowed the animals to be adapted. Thus, similar DMI among the groups was in the expected line. Our findings corroborated well with those available in literature (Chaudhary et al., 2017). Most notable effect of SMB supplementation that was observed in this experiment was on intake of N, as intake of CP was higher (p<0.05) in both T₂, T₃ and T₄ than control. The higher crude protein content of the SMB supplement was reflected in higher crude protein content of the supplemented diets. The SMB-I, SMB-II and SMB-III contained 15% urea, which caused higher intake of crude protein in the supplemented groups. Similarly, supplementation of urea molasses mineral improved the nitrogen content of the basal diet (Khadda et al., 2014).
 

 

               
The digestibility of DM, OM, CP, EE, NDF and ADF was similar among the groups (Table 2). Earlier reports showed that supplementation of urea molasses mineral blocks (UMMB) improved the digestibility of nutrients (Wadhwa et al., 2014; Choubey et al., 2015). However, such supplements are more effective when the basal ration contained less CP. The findings of this study corroborated well with the observation of other researchers (Patil et al., 2019; Ankita et al., 2019). It is of interest to note that even though there was an increase in N supply due to supplementation of SMBs, TDN supply was similar among the groups. To reap the benefits of increased supply of N and minerals, a synchronized supply of energy from an appropriate source is a pre-requisite (Kim et al., 1999).
       
All the animals in all the four groups were on positive nitrogen balance. The nitrogen intake was significantly (p<0.05) higher in SMB fed groups than control (Table 2). The improvement in N balance as a consequence of SMB supplementation could mainly be attributed to increased N intake without any negative influence on its digestibility. Bunting et al., (1989) found maximum balance of N for high protein diets than for low protein diets. The Ca and P balances were similar in all the groups and the animals were found to be in positive balance. In an earlier study a noticeable effect of UMMB supplementation with wheat straw was that the negative N, Ca and P balances associated with feeding wheat straw alone became positive balances of 2.90, 2.85 and 0.50 (g/d) for N, Ca and P, respectively which indicated that the blocks provided compensatory nutrients for those that are limiting with wheat straw alone (Garg and Gupta, 1992). In this experiment no dramatic improvement was noted because the control diet unlike in the previous experiment was a balanced diet supplying all nutrients. Event then a tendency of improvement (P=0.09) with respect to Ca balance was noted. This would probably infer towards beneficial effect of  effect of supplementary SMB.
 
Effect of feeding solid multinutrient blocks on haemato-biochemical profile
 
The mean values of Hb and PCV in animals ranged from 11.90 to 12.38 (g/dl) and 29.75 to 30.95 (%), respectively. These values were within the normal range of 8-15 g/dl and 24-46% quoted for cattle by Radostits et al., (2000). Similar results were also observed by Singh et al., (2010). In contrast, Hossain et al., (2011) reported that the blood Hb and haematocrit values were significantly (p<0.05) higher in UMMB supplemented groups than control in goat kids. Absence of significant variations in these parameters, therefore, is suggestive of an optimum nutrient availability to the calves irrespective of dietary treatments.  
       
Blood glucose levels were within the normal range for all treatments. However, the values were slightly higher on SMB supplemented groups compared to control diet. Similarly, Gendley, (2015) reported that higher level of blood sugar was obtained in UMMB supplemented groups than control in goats. This may be due to better nutrient availability from SMB that might have stimulated the production of propionic acid from cellulose. Since propionic acid is glucogenic in nature it might have been converted to glucose through the process of gluconeogenesis.The similar serum total proteins levels among the groups as observed  in the  present study indicate that the experimental feed has no deleterious effect on serum proteins. However, the serum albumin (mg/dl) levels at 150 day were significantly higher as compared to 0 day. These results were similar with the observation of Singh et al., 2010 and contrary with the results obtained by Muralidharan et al., (2015) who observed that the supplementation of UMMB increased serum protein (P<0.05) in supplemented groups whereas, serum albumin increased significantly (P<0.05) only in concentrate supplemented group (T₂). Such variation could be mostly attributed to level of supplement and more importantly on the nature of the basal diet. Most of the studies that reported a positive response for supplementation of nutrient blocks used a straw alone diet that was deficient in several nutrients. In this experiment, however, a balanced control diet was fed. Hence the results were within the expected line.
       
The average serum urea concentration was the highest in control group than SMB supplemented groups, however the differences were non-significant. These results are in agreement with the findings of earlier worker Raman et al., (2010) who observed decrease in serum urea concentration due to nutrient block supplementation. Serum urea concentration was higher in animals fed on roughage based rations supplemented with concentrate as compared to animals fed on UMMB supplemented ration. This may be due to slow release of ammonia from the blocks and blocks being available during 24 hrs was more uniformly available, whereas concentrate mixture was consumed immediately after feeding. Nevertheless, all serum urea concentration values in all the experimental animals were within normal range.
       
Serum creatinine levels can change when animals are either in a stress condition or when dietary energy supply is insufficient to maintain a normal physiological condition (Lehninger et al., 1993). There was no significant difference among the groups, but significant difference was observed at different period intervals. However, the mean values of serum creatinine found in present experiment were within the normal range of 1.0 to 2.7 mg%, as reported for the domestic animals (Kaneko, 1980). Similarly, Jain et al., (2005) observed non-significant changes in plasma creatinine levels in goats fed UMMB.
       
There was no variation in the activity of ALT and AST among the all experimental groups, which was in corroboration with Patil et al., (2017) who reported no effect of urea molasses supplementation on the activity of ALT and AST in mid lactating buffaloes. On the other hand, Hossain et al., (2011) reported that ALT and AST values increased significantly due to feeding of urea molasses mineral block supplement, Significant increase in serum AST activity in UMMB treated animals suggests an increased respiratory burst and mitochondrial involvement, as SGOT is chiefly a mitochondrial enzyme resulting from acute and chronic liver injury (Hassanein, 2004). In the present experiment the level of ALT and AST were comparable to the control group, depicting that supplementation of SMB had no any harmful and degenerative effect on hepatic cells and muscle tissues.
       
From these results, it may be concluded that supplementation of SMB  can replace 30% crude protein of concentrate mixture without any adverse effect on feed intake, digestibility, nutrient utilization and blood biochemical profile  of crossbred calves.

The authors are thankful to the Director, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly for providing necessary facilities to carry out this study.