Effect of utilization of corn cobs in total mixed ration on growth performance and nutrient utilization of growing goats

Introduction

To overcome the scarcity of dry fodders there is an urgent need for tapping some unconventional dry roughage sources. Corn cobs, a byproduct of maize production obtained after harvesting of maize grains, are a good alternate roughage source and can be utilized in ruminant rations. It can serve as an alternate source of feed. It is among the most accessible and plentiful agricultural wastes (Kategile et al., 1981) [7] . They have low nutritional value, but in the agricultural sector they are used as fuel, bedding for chickens and other animals, and even as feed for ruminants. These cobs are abundant in hemicellulose and cellulose but low in crude protein, making them a viable alternative feed source for ruminants. This significant amount of maize cobs may be used as an alternate source of roughage for ruminants and as a cheaper feeding option. The high amount of complex carbohydrates in corn cobs results in lower utilization; this might be improved if corn cobs are included in total mixed ratio in (TMR) form. Furthermore, it is reported that supplementation of fibrolytic enzymes to crop residues-based rations enhances utilization of feed and nutritional value of feed positively affecting performance of animals in terms of growth and lactation. When fibre digestion is impaired and energy is the diet's first-limiting nutrient, animals respond more strongly to enzyme supplements (Beauchemin et al., 2003) [4] .

Forage fed with exogenous enzymes decreased pH value, ammonia nitrogen, and CH4 production while increasing the digestibility of dry matter, neutral detergent fibre, and total volatile fatty acid yield. Thus, crop waste like corn cobs could be used as a roughage source in total mixed ration of ruminants which will act as good alternative roughage source during scarcity situation when there is a shortage of conventional roughage sources. Further, the utilization and nutritional value of such crop wastes can be enhanced by supplementation of fibrolytic enzymes. Considering the above facts in mind and huge availability of corn cobs in the area of research work, present research work was planned to evaluate the effect of utilization of corn cobs in total mixed ration on the growth performance and nutrient utilization of Osmanabadi growing goats with the following objectives. During the trial period, maximum 30 °C and minimum 24 °C temperature and 823 mm precipitation was recorded. The study involved 18 Osmanabadi growing goats of 4-5 months of age which were divided into three equal groups viz., T0 (Control), T1 and T2, having six goats in each group. The goats in the control group (T0) were fed total mixed ration (Concentrate: 30 parts, Dry roughages-Jowar straw (Kadbikutti): 50 parts and Green roughages-DHN6: 20 parts) to provide nutrients as ICAR (2013) [6] , whereas in the T1 group, goats were fed total mixed ration as per Group T0 where in Kadbikutti of dry roughage was replaced by corn cobs at 25% level, while in T2 group, the goats were fed total mixed ration as per Group T1 + fibrolytic enzymes @ 300g/ton of feed. The trial lasted for 90 days duration. The trial lasted for ninety days. The total mixed ration (TMR) comprising of 50% dry roughages -dry kadbikutti, 20% green fodder DHN6 and 30% concentrate mixture, was prepared every day in the morning at farm and fed throughout the experimental period of 90 days. The corn cobs utilized in treatment groups were obtained in coarsely ground form after threshing of corn grains from grain producing crops cultivated at ILFC, COVAS, Udgir. The corn cobs were again ground to appropriate size so that it can be mixed thoroughly in TMRs of treatment groups. The fibrolytic enzyme used in the present experiment was in a free-flowing powder form, easy to mix in feed. The fibrolytic enzyme consists of cellulase and hemicellulase (xylanase) enzymes which were helpful in efficient breakdown of cell wall and enhancing fibre digestibility. The said enzyme was procured from the market. The enzyme was supplemented to experimental animals through concentrate mixture which was included in TMR of group T2. The representative samples of concentrate mixtures, green fodder (DHN6), kadbi kutti, corn cobs and various TMRs utilized for feeding of experimental growing goats were collected at fortnight interval throughout the experimental period, oven dried and the pooled samples were analyzed as per AOAC (2007) [1] . The fecal samples obtained while conducting digestibility trial were also analyzed. The chemical composition (% DMB) of concentrate mixtures, green fodder (DHN6), Kadbi Kutti and corn cobs is presented in Table 1. Three different types of TMRs were prepared every day and used for feeding respective experimental groups to meet their nutrient requirements (ICAR, 2013) [6] . The ingredient composition of experimental TMRs is given in Table 2 and the percent chemical composition (% DMB) of total mixed ration of various experimental groups is presented in Table 3. Experimental growing goats were fed under stall feeding system with commonly routine managemental practices. Ad libitum. feeding practice was followed throughout the experimental period and feed left over weighed next day morning to calculate total dry matter intake. All the experimental animals were weighed at the start of experiment before feeding and watering and thereafter weighing was done every fortnightly at the same time. The digital weighing balance of 200 kg capacity was used for weighing the experimental animals. In the last week of the experiment a digestibility trial of seven days duration was conducted by total collection method. All the growing goats from each group were used for the digestibility trial. Observations of various parameters recorded during experimental period were tabulated and data were statistically analyzed as per Snedecor and Cochran (1994) [12] , by using Randomized block design and Completely Randomized Design.

Materials and Methods

Results and Discussion

The overall performance of growing goats from different experimental groups is presented in Table 4. The average body weights of growing goats from group T₂ were significantly (p < 0.01) higher than group T₁ and control; however, the difference between group T₀ and T₁ was statistically non-significant. The significant (p < 0.01) higher average fortnight wise body weights in group T₂ supplemented with fibrolytic enzymes might be due to better degradation of cell wall components and enhanced utilization of crude fibre. These results observed in present study are similar with results of Cruywagen and Goosen (2004) [5] who reported significant improvement in cumulative weight gain in Merino lambs fed with pre-enzyme treated wheat strawbased diets. Saleem et al. (2011) [11] also reported improvement in body weight for male sheep by the feeding of paddy straw-based complete feed supplemented with fibrolytic enzyme mixture. NE et al. (2017) [9] also observed a significant (p < 0.05) increase in total gain and average daily gain in growing barley lambs supplemented with exogenous fibrolytic enzyme @ of 2.5g m/h/day than that of control group. The average gain in weight was comparable among various experimental groups. These results are similar with results of Babale et al. (2015) [3] who observed no significant difference in weight gain in Red Sokoto bucks fed concentrate mixture consisting of raw corn cobs replacing maize bran at 10 and 20% level. Aregheore (1995) [2] also observed no significant differences in body weight gain among goats fed the different residues viz. ground nut shell, corn cobs and cocoa pod husk. The average daily dry matter intake of group T2 was significantly (p < 0.01) higher than group T0 and T1, however, difference between group T0 and T1 was comparable. The% DMI and DMI per unit metabolic body size of growing goats from various experimental groups was comparable. This also indicated that there was no adverse effect of replacing jowar straw withcorn cobs in TMR ration supplemented with or without fibrolytic enzymes on palatability of feed. The finding of present study resembles with Olamilusi et al.

(2019) [10] who observed highest dry matter intake in west African dwarf rams fed polyenzyme treated corn cob-based diet than polyenzyme untreated corn cob-based diet. In contrast Yuangklang et al. (2017) [13] observed no difference on dry matter intake of goats received rice straw base ration TMR with or without supplemental fibrolytic enzymes. Average TDN intake was significantly (p < 0.01) higher for group T₂ than group T₀ and T₁, but difference between group T₀ and T₁ were comparable. The higher TDN intake in group T₂ might be due to higher digestibility coefficients of all nutrients of TMR ration provided to group T₂. The findings of the present study corroborated with NE et al. (2017) [9] , who observed higher TDN intake in growing Barkey lambs fed ration supplemented with fibrolytic enzymes. The average DCP intake of growing goats from various experimental groups was comparable. The efficiency of feed utilization when considered in terms of DM, TDN and DCP required per kg gain in weight showed non-significant difference among various experimental groups. These results corroborated with Babale et al. (2015) [3] who observed no significant difference in feed conversion ratio in Red Sokoto bucks fed concentrate mixture consisting of raw corn cobs replacing maize bran at 10 and 20% level. Contrary to the findings of present study López-Aguirre et al.

(2016) [8] observed significant (p < 0.05) effect of supplementation of exogenous enzymes on FCE and FCR of growing Pelibuey lambs. Cruywagen and Goosen (2004) [5] also found significantly higher feed conversion efficiency in Merino lambs received pre-enzyme treated wheat straw-based diets.

The average digestibility coefficients of nutrients (Table 5) revealed significant effect of feed treatments. The average digestibility coefficients for dry matter of group T2 were significantly (p < 0.01) higher than T0 and T1 group. Further, it was seen that digestibility coefficient of dry matter for control group was significantly (p < 0.01) higher than group T1. The average digestibility coefficients for organic matter and crude protein of group T1 were significantly (p < 0.01) lower than T0 and T2 groups. Further, it was also seen that average digestibility coefficients of organic matter and crude protein for groups T0 and T2 were comparable. The average digestibility coefficients for ether extract, crude fibre and nitrogen free extract of group T2 was significantly (p < 0.01) higher than T0 and T1 groups. Further, it was revealed that digestibility coefficients for ether extract, crude fibre and nitrogen free extract were significantly (p < 0.01) higher in control group than group T1. The percentage TDN of TMR of group T2 was significantly (p < 0.01) higher than T0 and T1 groups, however, between group T0 and T1 it was significantly (p < 0.01) higher in group T1than T0. The percentage DCP of TMR of group T0 was significantly (p < 0.01) higher than T1 and T2 groups. Further, it was also seen that DCP of group T1 and T2 was comparable. Findings of the present study resembles those of NE et al. (2017) [9] , who reported improved dry matter, crude protein, crude fibre and nitrogen free extract as compared to control group when treated group of lambs were fed control ration plus 2.5 g exogenous fibrolytic enzyme. The means having common superscript in the same row do not differ significantly NS: Non-significant *Significant (p < 0.05) **Significant (p < 0.01)

The input-output relationship of the present study indicates that inclusion of fibrolytic enzyme in the group fed with TMR by partial replacement of 25% kadbi-kutti with corn cob, decreased the feeding cost and fetched more profit by Rs. 203.26 over control group fed TMR without corn cobs. However, net profit for control group was higher by Rs. 42.13 than group T1, fed with TMR by partial replacement of 25% kadbi-kutti with corn cob without fibrolytic enzyme supplementation.

Conclusion

From overall results of the present study it is concluded that the replacement of Kadbi kutti by corn cobs @ 25% in TMR with or without supplementation of fibrolytic enzymes has no adverse effect on growth performance and nutrient utilization of growing Osmanabadi goats. The replacement of Kadbi kutti by corn cobs @ 25% in TMR along with supplementation of fibrolytic enzymes @ 300 g/ton is found cost effective.

Acknowledgement

AcknowledgementWe thank Associate Dean, College of Veterinary and Animal Sciences, Udgir, Latur, Maharashtra for providing necessary facilities for carrying out this research work.

References

1. AOAC. Official methods of analysis. 18th ed. Washington DC: Association of Official Analytical Chemists; 2007.
2. Aregheore EM. Effect of sex on growth rate, voluntary feed intake and nutrient digestibility of West African dwarf goats fed crop residue rations. Small Rumin Res. 1995;15:217-221.
3. Babale DM, Kibon A, Yahaya MS. Performance and linear body measurements of Red Sokoto male goats on replacement levels of corn cobs for maize bran with cowpea husk basal diet. Net J Agric Sci. 2015;3(2):35-40.
4. Beauchemin KA, Colombatto D, Morgavi DP, Yang WZ. Use of exogenous fibrolytic enzymes to improve feed utilization by ruminants. J Anim Sci. 2003;81(14 Suppl 2):E37-E47.
5. Cruywagen CW, Goosen L. Effect of an exogenous fibrolytic enzyme on growth rate, feed intake and feed conversion ratio in growing lambs. S Afr J Anim Sci. 2004;34(2):71-73.
6. ICAR. Textbook of applied animal nutrition. Reddy DV, editor. 3rd ed. New Delhi: Oxford IBH Publishing Co. Pvt. Ltd.; 2013. p.167-172.
7. Kategile JA, Urio NA, Sundstol F, Mzihirwa YG. Simplified method for alkali treatment of low-quality roughages for use by small-holders in developing countries. Anim Feed Sci Technol. 1981;6(2):133-143.
8. López-Aguirre D, Hernandez-Melendez J, Rojo R, Sanchez-Davila F, Lopez-Villalobos N, Salem AFZ, et al. Effects of exogenous enzymes and application method on nutrient intake, digestibility and growth performance of Pelibuey lambs. SpringerPlus. 2016;5:1-6.
9. NE EB, HM ES, Hemmat S, AT M. Evaluation of exogenous fibrolytic enzyme supplementation to improve feed utilization in ruminants. J Environ Sci. 2017;39(1):69-90.
10. Olamilusi OD, Olotu J, Eniolorunda OO. Dry matter acceptability and digestibility of nutrients by West African dwarf rams fed polyenzyme treated cassava peel and corn cob-based diets. Niger J Anim Prod. 2019;46(2):202-208.
11. Saleem AZM, El-Adawy MM, Gado H, Camacho LM, González-Ronquillo M, Alsersy H. Effects of exogenous enzymes on nutrient digestibility and growth performance in sheep and goats. Trop Subtrop Agroecosyst. 2011;14:867-874.
12. Snedecor GW, Cochran WG. Statistical methods. Ames (IA): Iowa State University Press; 1994.
13. Yuangklang C, Schonewille JT, Alhaidary A, Vasupen K, Bureenok S, Seanmahayak B, et al. Growth performance and macronutrient digestion in goats fed a rice strawbased ration supplemented with fibrolytic enzymes. Small Rumin Res. 2017;154:20-22.