The results of the different experimental groups have been presented and discussed under the following subheads.
Body weight and nutrient intake
Effect of enzyme supplementation on body weight and nutrients intake on lactating Murrah buffaloes during winter season has been presented in Table 3. Body weight (BW) and metabolic body weight remained similar (P>0.05) in different treatment groups. Average body weight was 547.88, 551.00, 552.76 and 554.45 kg in T
1, T
2, T
3 and T
4 groups, respectively. Similar findings in buffaloes
(Shekhar et al., 2010) and in cattle
(Kung et al., 2000; Knowlton et al., 2007; Lopuszanka and Bilik 2011;
Barbadikar, 2012;
Dean et al., 2013) were also reported by earlier researchers.
Yang et al., (2000) also reported in cows fed the control diet, enzyme-treated TMR, or enzyme-treated barley-based concentrate had no effect on body weight changes. Similarly,
Knowlton et al., (2002) observed body weight in early lactating cows that were administered diets supplemented with enzymes.
Shojaeian and Thakur (2007) found that addition of enzymes to the urea-treated wheat straw-based TMR fed to dairy cows had no effect on body weight changes. However, because the buffaloes used in the present investigation were in both early and mid-lactation, no significant effect on the change in body weight was observed. Similar findings were also reported by several other workers
(Rode et al., 1999; Beauchemin et al., 2000 and
Titi, 2003). The overall average DMI in four treatment groups was 16.15, 16.36, 16.32 and 16.34 kg/d in T
1, T
2, T
3 and T
4 groups, respectively. There was no significant difference in DM intake between the control and the three treatment groups throughout the experimental period. The average DM intake (kg/100 kg body weight) was 2.93, 2.95, 2.95 and 2.95 kg for the T
1, T
2, T
3 and T
4 groups, respectively, which was almost similar and had no significant difference statistically. The difference in dry matter intake among treatment groups was found non-significant and almost similar in all four groups. Those results were similar with some other findings in cattle
(Mohamed et al., 2013; Dean et al., 2013; Dunda, 2015;
El-Bordeny et al., 2015). In case of buffalo,
Shekhar et al., (2010) did not find increase in DMI while the
Gaafar et al., (2010) found 4% higher DMI in enzyme supplemented group of buffaloes. The cumulative average of CP intake g/day and g/100 kg body weight due to the supplementation of the enzyme xylanase and cellulase in four treatment groups was 1446.69, 1475.22, 1479.66 and 1486.77; 253.72, 261.78, 268.02 and 273.00, respectively. The CP intake g/day and g/100 kg was found to be significantly higher in T
3 and T
4 group in buffaloes. The results were in agreement with
Romero et al., (2016) who reported that supplementation of Xylanase plus @ 1 mL/kg DM of TMR (T1) significantly (P<0.001) increased the DCP intake (kg/d) in Holstein cows. Average total TDN intake was 7.43, 7.83, 7.92 and 7.97 kg/day in control (T
1), T
2, T
3 and T
4 groups, respectively. Average TDN intake, kg/100 kg BW was 1.24, 1.37, 1.39 and 1.41 in control (T
1), T
2, T
3 and T
4 groups, respectively. The average TDN intake g/kg W
0.75 were 65.60, 68.95, 69.85 and 70.20 in control (T
1), T
2, T
3 and T
4 groups, respectively. The Average total TDN intake, kg/100 kg BW and g/kg W0.75 was significantly higher (P<0.05) in treatment groups supplemented with xylanase and cellulase in lactating Murrah buffaloes. The above findings provided additional support to the findings of similar reports indicating that the average TDN consumption in the enzyme supplemented group of Sahiwal cows, who were fed urea treated wheat straw, was considerably higher (P<0.01) as compared to the control group (
Shojaeian and Thakur 2007).
Shekhar et al., (2010) showed that the intake of total digestible nutrients (kg per day) was considerably greater in the group that received enzyme supplementation.
Nutrient utilization and digestibility coefficient
The data related to nutrient utilization and digestibility coefficient in lactating Murrah buffaloes among different treatment groups of buffaloes during winter season is presented in Table 4. Dairy animal’s daily intake of digestible nutrients, which is a function of both intake and digestibility, determines how well they perform. Forage digestibility was correlated with NDF digestibility and content (
Mertens, 2009). Average body weights were 557.62, 560.23, 563.39 and 567.17 kg in control (T
1), T
2, T
3 and T
4 groups, respectively which did not differ significantly among the different treatment groups. Similar trend was observed in case of metabolic body weight (W
0.75) which was 114.75, 115.15, 115.63 and 116.21 in control (T
1), T
2, T
3 and T
4 groups, respectively. Total DMI as kg/d and kg/100 kg bwt were 14.75 and 2.63 in control group (T
1), 14.80 and 2.69 in T
2 group, 15.08 and 2.68 in T
3 and 15.51 and 2.82 in T
4 group. The CP intake as kg/d and g/100 kg body weight was 1.46 and 255.25 in control group (T
1), 1.50 and 260.03 in T
2 group, 1.59 and 266.21 in T
3 and, 1.68 and 269.63 in T
4 group, respectively. The CP intake of the different enzyme supplemented groups differed significantly (P<0.05). Average TDN intakes expressed as kg/d, kg/100 kg body weight and g/kg W
0.75 were 7.54, 1.07, 65.73 in T
1 group; 7.78, 1.24, 67.56 in T
2 group; 7.88, 1.22, 67.19 in T
3 group and 7.90, 1.28 and 68.16 in T
4 group, respectively. No significant difference in TDN intake between the treatment groups due to enzyme supplementation was found during winter season. The CF, NDF and ADF digestibility improved significantly (P<0.05) in enzyme supplemented buffaloes during the winter season.
Knowlton et al., (2002); Bowman et al., (2002) and
Gado et al., (2009) reported similar results.
Titi and Tabbaa (2004) observed that supplementation of fibrolytic enzymes significantly (P<0.05) increased NDF digestibility.
Gaffar et al., (2010) reported that lactating buffaloes supplemented with cellulase and xylanase showed a significant (P<0.05) increase in crude fibre digestibility (CF). The results of present study were in agreement with the report of
Arriola et al., (2011) who found that lactating cows with added fibrolytic enzyme at varying levels of concentrate in diet and groups with higher concentrate proportions and enzyme supplementation had greater digestibility compared to the groups without supplementation.
El-Bordeny et al., (2017) added enzymes to Barkey lambs’ diet which resulted in a notable enhancement in the digestibility of many components such as DM, OM, CP, CF, NFE, NDF, ADF, Cellulase and hemicellulose. According to
Shekhar et al., (2010), there was a significant (P<0.05) increase in the digestion of CF, NDF and ADF. The result showed that the activity of the rumen bacteria responsible for breaking down fibrous materials might have been enhanced due to the combined action of externally added fibrolytic enzymes and the enzymes produced by the rumen microorganisms themselves.
Azam et al., (2017) found that increasing the amounts of enzyme supplementation in the diets of lactating Nili Ravi buffaloes considerably improved the digestibility of crude protein and NDF.
Milk yield and composition
The effects of enzyme supplementation on yield and composition of milk in lactating Murrah buffaloes during winter season have been summarized in Table 5. The average milk yield (kg/d) was 4.39, 5.02, 5.11 and 5.34 in T
1, T
2, T
3 and T
4 groups, respectively. The average milk yield (5.34 litre/day) was higher in T4 as compared to other treatment groups. Similarly, average milk yield was numerically higher in the enzyme supplemented groups as compared to control group. The analysis of variance revealed that there was non-significant difference in milk yield. Similar results were reported by
Elwakeel et al., (2007) who revealed that effect of enzyme supplementation was non-significant on milk yield.
Shojaeian and Thakur (2007) reported in Sahiwal cows fed urea treated wheat straw-based ration supplemented with xylanase and cellulase at 1.5 g/kg DM produced 9.98 percent more milk.
Arriola et al., (2011) investigated the impact of fibrolytic enzyme and found that enzyme supplementation increased milk yield at different concentrate amount, but the effect was statistically non-significant between groups. In winter season, it was found that effects among treatment groups on the milk composition of lactating Murrah buffaloes were statistically non-significant and the findings of the present study were in line with the results of
Vicini et al., (2003); Shojaeian and Thakur (2007) who also reported that the addition of enzyme supplements to dairy cows diets did not have any effect on the percentage of milk fat that was produced. According to
Miller et al., (2008) contents of milk protein and milk fat increased quadratically and linearly, upon enzyme supplementation on different dosages of liquid fibrolytic enzyme that were added to the diet of lactating cow.
Shekhar et al., (2010) did not find any marked increment in milk fat contents in enzyme supplemented Murrah buffaloes.
Mohamed et al., (2013) and
El-Bordeny et al., (2015) reported components like lactose, total solids, milk protein and SNF% were not affected by enzyme supplementation in buffaloes.
Azam et al., (2017) found milk protein, solids not fat, fat and lactose were not affected (P>0.05) by supplementation.
Liu et al., (2022) observed no statistically significant change in milk composition when tested on dairy cows given a cocktail of fibrolytic and amylolytic enzymes.