Effect of feeding forest foliages, rice straw and concentrate-based total mixed ration on nutrient utilization and growth in mithun (Bos frontalis)

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Livestock Science 117 (2008) 263 – 269 www.elsevier.com/locate/livsci

Effect of feeding forest foliages, rice straw and concentrate-based total mixed ration on nutrient utilization and growth in mithun (Bos frontalis) B. Prakash ⁎, A. Dhali, A. Mech, K. Khate, H. Moaakum, C. Rajkhowa National Research Centre on Mithun, Jharnapani, Medziphema, Nagaland-797106, India Received 4 December 2006; received in revised form 12 December 2007; accepted 13 December 2007

Abstract The study aimed to evaluate the effect of feeding Borrena hirticulata (BH), Ficus hirta (FH), rice straw (RS) and concentratebased total mixed ration (TMR) on nutrient utilization, rumen fermentation and growth in mithun. Growing male mithun calves were randomly allotted to 2 feeding groups (6 in each), TMR1 and TMR2. The TMRs consisted of RS 300 g kg− 1, concentrate 400 g kg− 1 and BH 300 g kg− 1 (TMR1) or FH 300 g kg− 1 (TMR2) on a dry matter (DM) basis. Both TMRs were fed ad libitum to the animals for 121 d and a digestibility study was conducted during the last 7 d of the experiment. To assess rumen fermentation, rumen fluid was collected at 2 h interval for 24 h. Apparent digestibility of DM, crude protein (CP) and crude fibre (CF) did not differ significantly between the TMRs. Nevertheless, apparent digestibility of ether extract was found to be significantly (P b 0.01) greater in TMR2 (0.59) compared to TMR1 (0.54). Body weight gain (BWG; g d− 1), DM intake (kg d− 1), CP intake (g d− 1) and feed efficiency (kg feed kg− 1 gain) were found to be significantly (P b 0.05) greater in TMR1 (548, 5.14, 713 and 9.28) compared to TMR2 (496, 4.91, 703 and 10.03). An insignificant positive association (r = 0.35) between DM intake and BWG, but a significant (P b 0.01) positive association (r = 0.74) between CP intake and BWG were evident. Rumen pH (5.71 to 7.18) and ammonianitrogen (8.0 to 25.0 mg/dl) did not differ significantly between the TMRs, but differed significantly (P b 0.01) at different h postfeeding. In contrast, rumen total volatile fatty acid (42 to 105 mM) and total nitrogen (40.4 to 90.3 mg/dl) differed significantly (P b 0.05) between the TMRs and at different h post-feeding. The study revealed that BH, FH, RS and concentrate-based TMRs may be fed to mithun for satisfactory growth. © 2007 Elsevier B.V. All rights reserved. Keywords: Total mixed ration; Nutrient utilization; Body weight gain; Rumen fermentation; Mithun

1. Introduction Mithun (Bos frontalis) is a domesticated form of wild gaur and found mainly in the northeastern hill region of India. It is also found in Bhutan, Myanmar, Bangladesh and China (Simoons, 1984). Mithun is mainly reared for ⁎ Corresponding author. Tel./fax: +91 3862247341. E-mail address: [email protected] (B. Prakash). 1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.12.021

beef production. Besides, this animal also plays an important role in the socio-cultural life of its owners. Population of this animals is 0.28 million in India with an annual growth rate of 7.6% over the last two decades (Dhali et al., 2006). Steep hilly forest (300 to 3000 m above mean sea level) is the natural habitat of this unique free-range domesticated bovine. Weight of adult animals varies from 400 to 700 kg and growth rate of calves is reported to be 306 to 370 g d− 1 (Pal et al.,

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2004). The importance of scientific and economic mithun farming has been realized recently to augment the productivity. At this context, it is important to develop suitable feeding strategies using locally available foliages and crop residues. Nutrient utilization and digestibility of feed stuffs are related to nutritional quality. Production of different rumen metabolites depends on the concentration and quality of different nutrients in feed. Rumen pH decreases significantly at 4 h post-feeding in cattle (Giri et al., 2005). Total volatile fatty acid (VFA) production depends on the availability of readily fermentable substrates (Hess et al., 1996). Rumen ammonia-nitrogen (NH3-N) concentration depends on protein degradability and availability of readily fermentable energy and affects microbial protein production (Rook et al., 1987). Borrena hirticulata (BH) is one of the important foliages consumed by mithun and available in large quantity during August to January. Ficus hirta (FH) is a medium sized perennial tree that grows to 15 m. FH leaves are abundantly available throughout the year in mithun inhabited areas. Rice (Oryza sativa) is a major crop in mithun inhabited areas, but due to lack of awareness, feeding rice straw (RS) to ruminants especially to mithun is not a common practice. The study aimed to evaluate the effect of feeding forest foliages, RS and concentrate-based total mixed ration (TMR) on nutrient utilization, rumen fermentation and growth in mithun. Two important forest foliages, BH and FH were selected for this study.

chopped to 3–4 cm using an electrically operated chaff cutter. Two different TMRs were formulated to meet the nutrient requirement of cattle calves for 500 g d− 1 BW gain (BWG) according to the NRC standard (2001). TMR1 consisted of BH 300 g kg− 1, RS 300 g kg− 1 and concentrate 400 g kg− 1 on a dry matter (DM) basis. TMR2 consisted of FH 300 g kg− 1, RS 300 g kg− 1 and concentrate 400 g kg− 1 on a DM basis. The concentrate consisted of maize powder 250 g kg− 1, rice polishings 200 g kg− 1, wheat bran 250 g kg− 1, mustard oil cake 250 g kg− 1, salt 25 g kg− 1 and mineral mixture 25 g kg− 1. Each kg of mineral mixture contained vitamin A 2,0000,00 IU, vitamin D3 410,000 IU, vitamin B2 0.52 g, vitamin E 350 IU, vitamin K 0.4 g, calcium pantothenate 1 g, vitamin B12 3 mg, choline chloride 24 g, calcium 340 g, manganese 11 g, iodine 0.4 g, zinc 6 g, iron 3 g, copper 0.8 g and cobalt 0.18 g. 2.3. Experimental design and sample collection

2. Materials and methods

Six animals were randomly allotted to each treatment (TMR1 and TMR2). Average (mean ± SE) initial BW was 125.0± 1.5 and 118.0 ± 2.3 kg, respectively in TMR1 and TMR2. The animals were fed in cages for the entire experimental period (121 d). For each treatment, a digestibility study was conducted during the last 7 d of the experiment. During the digestibility study, feed and faeces samples were collected daily, composited and stored for analysis. On the last day of the experiment, approximately 15 ml of rumen liquor was collected from all the animals at 2 h interval for 24 h. Rumen liquor was collected with a 16 gauge supra spinal needle and necessary aseptic measures and guidelines were followed as per the recommendations of Institute Animal Ethics Committee. Rumen liquor was strained through a multi-layered cheese cloth and stored at −20 °C after adding a drop of 20% sulphuric acid. Approximately 15 ml of rumen liquor was collected separately for pH estimation.

2.1. Experimental animals, feeding and management

2.4. Analytical methods

Male mithun calves (n = 12) were selected from the herd of National Research Centre on Mithun, Nagaland, India. The experimental animals were acclimatized for two months. During the acclimatization period, the animals were fed 1.5 kg concentrate, ad libitum tree foliages and Napier grass per day. The animals were offered ad libitum water in morning and evening. During this period, the animals familiarized with metabolic cages. Before starting the experiment, the animals were vaccinated against foot and mouth disease, dewormed and treated for ectoparasites. Body weight (BW) of the animals was measured before morning feeding for three consecutive days at the beginning and end of the experiment and average BW was considered as the initial and final BW respectively.

The ingredients of concentrate, BH, FH and RS were analyzed for DM, crude protein (CP) and neutral detergent fibre (NDF) before (20 d) starting the experiment and different TMRs were formulated accordingly. During the experiment (0 to 120 d), BH and FH samples were collected at 20 d interval and analyzed for DM, CP and NDF. Besides, BH and FH samples that collected on 0 and 120 d were also analyzed for ether extract (EE), acid detergent fibre (ADF), lignin and ash. The samples of TMR1 and TMR2 were collected on 0 and 120 d and analyzed for DM, CP, EE, NDF, ADF, lignin and ash. The concentrations of total phenolics, non-tannin phenolics and condensed tannin were estimated in BH and FH on the last day of the experiment. The samples were analyzed for DM after drying at 105 °C for 24 h (AOAC, 1990; Method # 925.40), CP by Kjeldahl method after acid hydrolysis (AOAC, 1990; Method # 984.13), EE by Soxhlet method (AOAC, 1990; Method # 920.39), Crude fibre (CF) by (AOAC, 1990; Method # 978.10), ash by igniting at 550 °C for 3 h in a muffle furnace (AOAC, 1990; Method # 923.03) and ADF (AOAC, 1990;

2.2. Preparation of TMRs RS was harvested manually from field, sun dried for 6 d, chopped to 6–8 cm using an electrically operated chaff cutter and stored. BH and FH foliages were procured daily from forest (altitude 300 to 600 m above mean sea level) and

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Table 1 Chemical composition (g kg− 1 dry matter) of Borrena hirticulata, Ficus hirta, rice straw and concentrate mixture Parameters

Dry matter Crude protein Ether extract NDF ADF Lignin Ash Total phenolics Non-tannin phenolics Condensed tannin

Borrena hirticulata (± SE)

Ficus hirta (± SE)

0d

0d

124 ± 0.4 184 ± 2.5 12.8 ± 0.10 396 ± 0.6 291 ± 0.6 71.8 ± 0.12 118 ± 1.15

120 d 152 ± 0.6 165 ± 0.6 13.4 ± 0.11 421 ± 0.9 340 ± 2.9 89.0 ± 0.56 123 ± 0.56 55 ± 0.46 29 ± 0.55 32 ± 0.06

224 ± 0.9 200 ± 1.1 21.1 ± 0.18 417 ± 2.4 283 ± 1.3 51.0 ± 0.03 62.0 ± 0.09

Significance

120 d

Day (t)

Foliage (f)

t × f interaction

283 ± 0.4 174 ± 0.9 17.3 ± 0.13 491 ± 1.8 342 ± 1.6 93.0 ± 0.69 54.0 ± 0.15 63 ± 0.62 21 ± 0.57 41 ± 0.20

⁎⁎ ⁎⁎ ⁎⁎ ⁎⁎ ⁎⁎ ⁎⁎ Ns

⁎⁎ ⁎⁎ ⁎⁎ ⁎⁎ Ns ⁎⁎ ⁎⁎

⁎⁎ ⁎ ⁎⁎ ⁎⁎ ⁎⁎ ⁎⁎ ⁎⁎

Rice straw (±SD)

Concentrate mixture (± SD)

873 ± 1.8 54.0 ± 0.2 10.0 ± 0.50 713 ± 3.5 520 ± 1.7 83.0 ± 0.88 94.0 ± 1.37

938 ± 8.1 183 ± 2.4 62.0 ± 0.54 318 ± 1.7 142 ± 0.7 39.0 ± 0.50 66.0 ± 1.40

Ns: non-significant, ⁎: P b 0.05, ⁎ ⁎: P b 0.01, NDF: neutral detergent fibre; ADF: acid detergent fibre; 0 d and 120 d indicate the days of the experiment; Analysis was done in triplicate.

Method # 973.18). NDF content of the samples was analyzed as described by Van Soest et al. (1991) without heat stable amylase and expressed exclusive of residual ash. Total phenolics and non-tannin phenolics were estimated as described by Makkar et al. (1993). Condensed tannin was estimated as described by Porter et al. (1986). Total VFA concentration in strained rumen liquor (SRL) was determined by steam distillation using Markham's distillation apparatus (Barnett and Reid, 1957). NH3-N and total N were estimated in SRL using micro-Kjeldahl procedure (Sastry et al., 1999).

ADF content did not differ between the foliages and ash content did not differ between the days (Table 1). Lesser CP and greater NDF content was observed in both the foliages at the end of the experiment (Table 1). DM and NDF (P b 0.01) content of the foliages increased as the

2.5. Statistical analysis All the statistical analyses were performed using SPSS software package, version 10.0.1 (SPSS Inc., Chicago, USA). Variation in chemical composition of the foliages and TMRs was analyzed by ANOVA. The model included day of the experiment and foliage or TMR as source of variation. Variation in chemical composition of the foliages on different day of the experiment was analyzed using repeated measure ANOVA. The model included day as source of variation. Variation in BW parameters, feed efficiency, nutrient intake and digestibility was analyzed by ANOVA. The model included TMR as source of variation and initial BW as covariate. Diurnal variation in rumen pH and concentrations of different rumen metabolites were analyzed by ANOVA followed by multiple pairwise mean comparisons using Student–Newman–Keuls test. The model included time and TMR as sources of variation. Pearson's correlation analysis was performed to study the association between different experimental parameters.

3. Results 3.1. Chemical composition, nutrient utilization and BWG Effect of day and foliage was found to be significant (P b 0.01) on DM, CP, EE, NDF and lignin content, but

Fig. 1. Variation (mean ± SE) in nutrient composition of Borrena hirticulata (Panel A) and Ficus hirta (Panel B) on different days of the experiment. Effect of day was significant (P b 0.01). DM: dry matter; CP: crude protein; NDF: neutral detergent fibre. Analysis was done in triplicate.

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Table 2 Chemical composition (g kg− 1 dry matter) of the total mixed rations (TMR) Parameters

Dry matter Crude protein Ether extract NDF ADF Lignin Ash

TMR1

TMR2

Significance

0 d (± SE)

120 d (± SE)

0 d (± SE)

120 d (± SE)

Day (t)

Diet (d)

t × d interaction

674 ± 0.37 145 ± 0.36 31.6 ± 0.6 459 ± 0.33 300 ± 0.17 62.0 ± 0.46 90.0 ± 0.51

683 ± 0.57 140 ± 0.44 32.0 ± 0.57 467 ± 0.06 315 ± 0.57 67.2 ± 0.27 91.3 ± 0.20

704 ± 0.47 149 ± 0.14 34.1 ± 0.23 466 ± 0.63 298 ± 0.92 55.9 ± 1.61 73.2 ± 0.66

722 ± 0.58 141.8 ± 0.21 33.0 ± 0.58 488 ± 0.87 313 ± 0.39 68.5 ± 0.34 70.0 ± 0.28

⁎⁎ ⁎⁎ Ns ⁎⁎ ⁎⁎ ⁎⁎ Ns

⁎⁎ ⁎⁎ ⁎ ⁎⁎ ⁎ ⁎⁎ ⁎⁎

⁎⁎ ⁎ Ns ⁎⁎ Ns ⁎⁎ ⁎⁎

Ns: non-significant; ⁎: P b 0.05; ⁎⁎: P b 0.01; NDF: neutral detergent fibre; ADF: acid detergent fibre; 0 d and 120 d indicate the days of the experiment; Analysis was done in triplicate.

experiment progressed, but a reverse trend was observed for CP content (Fig. 1). A negative association (r = −0.94, P b 0.01) between CP and NDF and a positive association (r = 0.95, P b 0.01) between DM and NDF content were observed. Total phenolics, non-tannin phenolics and condensed tannin concentrations in the foliages are given in Table 1. DM, CP, NDF, ADF and lignin content differed significantly (P b 0.05) between the TMRs and day of the experiment (Table 2). EE and ash content differed significantly (P b 0.05) between the TMRs, but did not differ between days of the experiment (Table 2). CP content of the TMRs was found to be lesser on 120 d compared to 0 d of the experiment. In contrast, a reverse trend was observed for DM, NDF, ADF and lignin content

Table 3 Change in body weight (BW) gain (BWG), nutrient intake, plane of nutrition and apparent digestibility coefficient of nutrient in mithun (n = 6/group) fed different total mixed rations (TMR) Parameters

TMR1

TMR2

SEM Significance

Change in BW (kg) BWG (g d− 1) DM intake (kg d− 1) DM intake (% BW) DM intake (g kg− 1 metabolic BW) CP intake (g d− 1) CP intake (g kg− 1 metabolic BW) Feed efficiency (kg feed kg− 1 gain) Apparent digestibility of DM Apparent digestibility of CP Apparent digestibility of EE Apparent digestibility of CF

66.79 548 5.14 2.67 100

59.18 496 4.91 2.76 101

4.53 7 0.06 0.03 1

Ns ⁎⁎ ⁎ Ns Ns

713 13

703 14

2 0.2

⁎⁎ Ns

9.28 0.64 0.63 0.54 0.59

10.03 0.10 0.61 0.64 0.59 0.58

0.01 0.01 0.01 0.01

(Table 2). BWG, DM intake (DMI), CP intake and feed efficiency were found to be significantly (P b 0.05) greater in TMR1 (Table 3). Apparent digestibility of DM, CP and CF did not differ significantly between the TMRs. Nevertheless, apparent digestibility of EE was found to be significantly (P b 0.01) greater in TMR2 (Table 3). An insignificant positive association (r = 0.35) between DMI and BWG, and a significant positive association (r = 0.74, P b 0.01) between CP intake and BWG were evident. 3.2. Rumen fermentation Diurnal variation in rumen pH, total VFA, total N and NH3-N are depicted in Figs. 2–4. Rumen pH and NH3-N did not differ significantly between the TMRs, but differed significantly (P b 0.01) at different h postfeeding. In contrast, total VFA and total N differed significantly (P b 0.05) between the TMRs and at different h post-feeding. Rumen pH was found to be highest at 0 and 24 h and decreased at 3 to 4 h post-feeding. Total VFA was found to be highest at 10 h, and total N and NH3-N increased significantly (P b 0.01) at 1 to 2 h post-feeding.

⁎⁎ Ns Ns ⁎⁎ Ns

DM: dry matter; CP: crude protein; EE: ether extract; CF: crude fibre; SEM: standard error mean; Ns: non-significant; ⁎: P b 0.05; ⁎⁎: P b 0.01.

Fig. 2. Effect of feeding total mixed rations (TMR) on diurnal variation (mean ± SE) of rumen pH in mithun (n = 6/group). Arrow indicates the time of feeding. Effect of time was significant (P b 0.01).

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4. Discussion This study describes the effect of feeding forest foliage, RS and concentrate-based TMRs on nutrient utilization, rumen fermentation and growth in mithun. The results indicated that the nutrient utilization and growth performance were satisfactory in the experimental animals fed on these TMRs. 4.1. Nutrient composition, nutrient intake and growth performance Chemical composition of BH and FH was found to be similar with the previous report (Pal and Bujarbaruah, 2002). A significant increase in CP and decrease in DM and NDF content in both the foliages were evident as the experiment progressed, which might be attributed to plant maturity (Cogswell and Kamstra, 1976; Kilcher, 1981; Balde et al., 1993). It is known that DM and NDF content increases with plant maturity because of greater cell wall lignification (Sankhyan et al., 1999). The variation in nutrient composition of the TMRs at the beginning and end of the experiment was probably due to the variation in foliage nutrient composition. DMI was found to be significantly higher in TMR1 compared to TMR2, but apparent digestibility of DM, CP and CF did not differ between the TMRs. NDF content was found to be significantly lesser in TMR1 compared to TMR2. It is reported that DMI increases with increased palatability (Ketelaars and Tolkamp, 1992) and digestibility (Oba and Allen, 1999; Cherney et al., 2004), but decreases with increased dietary NDF (Reid et al., 1988; Orskov et al., 1991). Previous reports indicate that NDF has a negative effect on nutrient utilization (Nsahlai et al.,

Fig. 3. Effect of feeding total mixed rations (TMR) on diurnal variation (mean ± SE) of rumen total volatile fatty acid (VFA) in mithun (n = 6/ group). Arrow indicates the time of feeding. Effect of TMR, time and TMR × time interaction was significant (P b 0.01).

Fig. 4. Effect of feeding total mixed rations (TMR) on diurnal variation (mean ± SE) of rumen total nitrogen (total N) and ammonia-nitrogen (NH3-N) in mithun (n = 6/group). Arrow indicates the time of feeding. For total N, effect of TMR (P b 0.01), time (P b 0.01) and TMR × time interaction (P b 0.05) was significant. For NH3-N, effect of time was significant (P b 0.01).

1994; Larbi et al., 1998; Getachew et al., 2004). The results of this study indicated that probably DMI was not influenced by nutrient digestibility and greater DMI in TMR1 might be due to high palatability and low NDF content. DMI (100 g kg− 1 metabolic BW) was comparable with that of cattle and buffalo (56–120 g kg− 1 metabolic BW; Ranjhan, 1993) and was found to be greater than the previous report in mithun (88–98 g kg− 1 metabolic BW) fed on mixed tree leaves and concentratebased TMRs (Prakash et al., 2005). An insignificant positive association between DMI and BWG and a significant positive association between CP intake and BWG were observed. The greater BWG (9.5%) in TMR1 compared to TMR2 might be due to greater DM (4.5%) and CP intake (1.4%). Previous report in mithun also indicates that BWG and nutrient intake are positively associated (Pal et al., 2001). In this study, BWG was found to be comparatively higher than the previous report in mithun fed on rice bran and forest grass-based diets (Pal et al., 2004). This might be due to the fact that the experimental animals were on a better plane of nutrition. The greater feed efficiency in TMR1 compared to TMR2 might be due to lesser DMI per 100 kg BW and comparatively higher final BW. The concentration of condensed tannin in BH (32 g kg− 1 DM) and FH (41 g kg− 1 DM) was found to be within the permissible limit. It is suggested that condensed tannin does not influence rumen microbes and nutrient utilization if the level is less than 60 g kg− 1 DM (Barry and Manley, 1984; Reed, 1995). It may be assumed that the concentration of condensed tannin in the TMRs was low as these contained only 30% foliages. Therefore, it was unlikely that tannin

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had an adverse effect on nutrient utilization by the experimental animals. 4.2. Rumen fermentation pattern The range of rumen pH was found to be 5.71 to 7.18. It is reported in cattle that rumen pH of 6.2 to 7.1 is optimum for fibre digestion (Mertens and Loften, 1980; Giri et al., 2005). In contrast, rumen pH of 5.8 to 6.2 that are cyclic and of short duration causes a moderate reduction in fibre digestion (Hoover, 1986). In our experiment, rumen pH decreased below 6.2 for a short duration (2 h in TMR1 and 6 h in TMR2). The results indicated that the observed range of rumen pH probably did not have any adverse effect on rumen fermentation. Rumen pH significantly declined at 3 to 4 h postfeeding, which was in agreement with the previous report in cattle (Giri et al., 2005). Total VFA production was found to be comparable (Rodriguez et al., 1997; Giri et al., 2005) and lesser (Rotger et al., 2005) with the previous reports in cattle. A sharp increase in VFA concentration immediately after the first feeding was evident and it increased continuously thereafter. Peak VFA concentration was observed after 3 h of the second feeding and the concentration declined gradually thereafter. It is reported that VFA production attains peak at 12 h post-feeding (Rotger et al., 2005). The effect of TMR was found to be significant on total VFA concentration. During most part of the 24 h sampling period, VFA concentration was found to be greater in TMR1 compared to TMR2. The results indicated that TMR1 probably contained more fermentable substrate compared to TMR2 (Hess et al., 1996). Rumen NH3-N concentration was found to be within the range of 8.0 to 25.0 mg/dl with an average of 14.6 mg/dl. NH3-N concentration of 5 mg/dl is considered to be the minimum requirement for an optimal microbial growth in the rumen (Satter and Slyter, 1974). The observed NH3-N level suggested that the TMRs were adequate to support the satisfactory rumen microbial fermentation. In both the TMRs, a sharp increase in rumen total N concentration was observed at 2 h after the first feeding and the concentration was maintained thereafter throughout the sampling period. The result indicated that the TMRs might have contained steadily degradable protein that maintained a steady total N level over a long period (Davis and Stallcup, 1964). Significantly greater total N concentration in TMR1 compared to TMR2 indicated that TMR1 probably contained more steadily degradable protein.

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