Research Article

 

Effects of Different Forages in Fermented Total Mixed Rations on Nutrient Utilization and Ruminating Behaviours of Growing Yellow Cattle in Vietnam

 

Dinh Van Dung, Le Dinh Phung*, Le Duc Ngoan, Nguyen Xuan Ba, Nguyen Huu Van, Le Duc Thao

Faculty of Animal Sciences and Veterinary Medicine, Hue University of Agriculture and Forestry, Hue University, Hue city, Vietnam.

 

Received | September 17, 2019; Accepted | February 17, 2020; Published | March 05, 2020

*Correspondence | Le Dinh Phung, Faculty of Animal Sciences and Veterinary Medicine, Hue University of Agriculture and Forestry, Hue University, Hue city, Vietnam; Email: ldphung@hueuni.edu.vn

Citation | Dung DV, Phung LD, Ngoan LD, Ba NY, Van NH, Thao LD (2020). Effects of different forages in fermented total mixed rations on nutrient utilization and ruminating behaviours of growing yellow cattle in Vietnam. Adv. Anim. Vet. Sci. 8(3): 245-251.

DOI | http://dx.doi.org/10.17582/journal.aavs/2020/8.3.245.251

ISSN (Online) | 2307-8316; ISSN (Print) | 2309-3331

Copyright © 2020 Dung et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

 

INTRODUCTION 

 

In Vietnam, livestock production plays a very important role, not only in providing high value protein products for human consumption, increasing income, improving the living standard of smallholder farmers, but also contributing to crop cultivation by supplying valuable manure (Roubík et al., 2018). Cattle production is one of the most important livestock husbandries for smallholder farmers and has become more and more important in agricultural systems for household livelihoods in Vietnam (Dung et al., 2013). In 2017, the number of beef cattle in Vietnam reached about 5.35 million heads for a total living weight around 231.7 thousand tones, a respective rise of 2.75% and 4.11% compared to 2016 (Roubík et al., 2017). However, beef consumption of Vietnamese is still low, only 4.3 kg/person/year (GSO, 2017). Cattle production in Vietnam is characterised by low growth rate. This is mainly due to the poor feeding regime (Dung et al., 2013).

Vietnam is an agricultural country, with significant amounts of agricultural by-products such as cassava foliage, corn foliage, rice straw, sugarcane leafy tops. Annually, Vietnam has about 5.2 million tons of cassava foliage, 17.7 million tons of corn foliage, 5.6 million tons of sugarcane leafy tops, and many other agricultural by-products (GSO, 2017). All these forages are good feed sources for ruminant (Dung et al., 2013). However, the use of those forage sources for ruminant in Vietnam is still limited due to the fact that these forages are highly seasonal availability, while farmers are not used to process and store them for long year around use. Usually from March to July, many agricultural by-products are not eaten up, but in the rainy season (usually from September to December) the feed for ruminant is not enough (Dung et al., 2013). Previous studies such as Xu et al. (2014), Mirzaei et al. (2018) reported that, different forage sources did not affect feed intake of ruminant. In contrast, Ranathunga et al. (2010) reported that, different forage sources containing different levels of fiber lead to differences in DM intake and nutrient digestibility. The effects of forage sources on nutrient digestibility also are very different among studies. Porter et al. (2007) and Santos et al. (2011) documented that, forage sources had effect on DM digestibility; however, Castells et al. (2012) reported that, DM and OM digestibilities were not affected by different forage sources in diets. Most of studies concluded that using forage sources from agricultural by-products in ruminant feeding could reduce the cost for animal production and enable efficient utilization of crop residues as potentially useful feed resources (Walli et al., 2012). However, agricultural by-products are characterised by high fiber content and low digestibility. These limit their nutritive values for ruminant (Fon et al., 2012). Quality of forage sources from agricultural by-products should be improved by processing in order to increase their nutritive values for animals, one of the solution is total mixed ration (TMR). There is little information on effects of forage sources in fermented total mixed ration (FMTR) on feed intake, digestibility and ruminant behaviours of cattle.

 

Therefore, the objective of this study was to evaluate the effects of forage sources from agricultural by-products in FTMRs on feed intake, nutrient digestibility, pH, NH­­3-N and VFA concentration in the rumen fluid and ruminating behaviours of growing local yellow cattle.

 

MATERIAL AND METHODS

 

The experiment was conducted at the Experimental Farm of Faculty of Animal Sciences and Veterinary Medicine, Hue University of Agriculture and Forestry, Hue University, Thua Thien Hue province (16°00’ to 16°48’ latitude, 107°48’ to 108°12’ longitude), Vietnam.

 

Animal, diet and experimental design

Four male growing yellow cattle, 12 months of age, with initial live weight of 136.1 ± 9.44 kg (mean ± standard deviation) were used in a 4x4 Latin square design experiment. Treatments were forage sources namely corn foliage (FTMR1), cassava foliage (FTMR2), sugarcane leafy tops (FTMR3) and elephant grass (FTMR4). All forages were chopped 1-2 cm prior to mixing with brewers’ grains, maize meal, cassava meal, soybean meal, salt and premix vitamin-mineral, and the mixture was fermented at least 21 days before feeding the animal. Forage sources accounted 60% of FTMR (DM basis). The FTMR were provided ad libitum. Cattle were fed three times a day at 07.15, 13.00 and 16.30 hours. The ingredient and chemical composition of FMTR were presented in Table 1.

 

Table 1: Ingredients and chemical composition of fermented total mixed ration (FTMR).

 

Item	Treatments1
	FTMR 1	FTMR 2	FTMR 3	FTMR 4
Ingredient (% DM basis)
Corn foliage	60	-	-	-
Cassava foliage	-	60	-	-
Sugarcane leafy tops	-	-	60	-
Elephant grass	-	-	-	60
Brewers’ grain	8	2	5	5
Maize meal	10	17	10	11
Cassava meal	10	19	7	12
Soybean meal	10	0	16	10
Premix vitamin-mineral2	1	1	1	1
Salt	1	1	1	1
Chemical composition (%DM)
Dry matter	39.1	42.4	44.5	38.3
Organic matter	92.0	90.6	93.4	92.0
Crude protein	13.5	14.3	12.6	12.7
Neutral detergent fibre	41.1	35.6	50.0	40.9
HCN (mg/kg DM)	-	24.4	-	-

 

1Forage sources in FTMR 1: Maize foliage; FTMR 2: Cassava foliage; FTMR 3: Sugarcane leafy tops; FTMR 4: Elephant grass; 2Pemix vitamin – mineral: Vitamin A: 3,600,000 UI/kg; vitamin D3: 300,000 UI/kg; vitamin E: 4,000 mg/kg; vitamin B1: 500 mg/kg; vitamin B2: 1,000 mg/kg; vitamin B6: 650 mg/kg; vitamin B12: 6 mg/kg; vitamin C: 12,000 mg/kg; vitamin K3: 300 mg/kg; Biotin: 16 mg/kg; Folic acid: 100 mg/kg; vitamin B5: 2,500 mg/kg; niacin: 5000 mg/kg; Cholin Chloride (Fe, Zn, Cu, Mn, Mg): 40,000 mg/kg.

 

Each cattle was kept in an individual pen, where water was accessible without restrictions. The experiment consisted of four periods, each period lasted for 26 days. During the first 21 days, all cattle were adapted with their feeds, and the last 5 days was for samples collection. All animals were treated for internal parasites and liver fluke with Bioxinil (Bio Pharmachemie, Ho Chi Minh city) and vaccinated for pasteurellosis with P15 vaccine (NaVetCo, Ho Chi Minh city), and food and mouth disease prior to the experiment.

 

Data collection and sampling procedures

From days 22nd to 26th of each period, the intake of feed for each cattle was recorded daily and sampled for measuring DM intake and nutrient digestibility. Faeces were quantitatively collected. At the end of each day, total faeces were weighed, thoroughly mixed, subsampled (5% of mixed faeces) and stored at -200C for later chemical analyses.

 

The pH value, NH3-N and VFA concentration in the rumen fluid were measured daily from days 25th to 26th of the period. A vacuum-pump machine (MEDI-PUMP, USA) was used to collect rumen fluid via a stomach tube at 7.00h (0hrs) before the morning feeding and 11.00h (4hrs after the morning feeding). About 250-300 ml of the rumen fluid was collected each time and the pH value was measured immediately by a pH meter (Schott, Germany). Rumen fluid was then filtered through four layers of muslin cloth and a 50 ml subsample of each animal was used to analyze NH3-N and VFA concentration.

 

Feeding behaviour observation methods

The behaviours of individual cattle were recorded by cameras for 48 hrs (2 days). The video from cameras was used to analyse the feeding behaviours (eating/ruminating/resting time). Defecating frequency and urinating frequency were recorded on a plotting paper. The chewing time was calculated by adding the eating time and ruminating time, and the feed value index was calculated based on the chewing time per unit DM intake (Lee at al., 2010). The eating, ruminating and chewing efficiencies were calculated by dividing the DM intake by the eating, ruminating and chewing time, respectively. Chewing time= Eating time + Ruminating time; Eating rate= DM intake (g/d)/eating time (h/d); Ruminating efficiency= DM intake (g/d)/ruminating time (h/d); Chewing efficiency= DM intake (g/d)/chewing time (h/d); And feed value index = Chewing time/DM intake (1kg) (Lee at al., 2010).

 

Chemical analyses

Samples of feeds and faeces were dried at 600C and ground (1 mm screen using the Retsche, Germany) and analyzed using standard methods of AOAC (1990) for DM and ash. NDF was determined as described by Van Soest et al. (1991). Total N was determined according to AOAC (1990) and the concentration of CP was calculated as N×6.25.


Rumen fluid was immediately measured for pH using a pH meter (Schott, Germany). The NH3-N concentration of the rumen fluid was measured by the Kjeldahl method (AOAC, 1990). VFAs were measured by gas chromatography in the Lab of Okayama University, Japan.

 

Statistical analyses

All data were statistically analyzed for a Latin square design using the General Linear Models procedure of SPSS 16.0. Data were analyzed using the following model:

 

Yijk = µ + Ti + Cj + Rk + eijk

 

Where; Yijk is the dependent variables, receiving treatment i; animal j; period k; µ is the overall of mean; Ti is the effect of treatment i (i=1=FTMR 1; i=2=FMTR 2; i=3=FMTR 3 and i=4=FMTR 4); Cj is the effect of animal j; Rk is the period effect; eijk is the residual effect. The differences between means were compared using a least significant difference method (LSD). Statistical difference was declared at P<0.05.

 

RESULTS

 

Feed intake and digestibility

The forage sources in FTMRs had no significant effect (P>0.05) on the DM intake (both in kilograms per day and percentage of the body weight). However, the forage sources in FMTRs significantly affected DM and OM digestibilities (P<0.05), whereas CP and NDF digestibilities were not significantly affected (P>0.05) by forage sources in FMTRs (Table 2).

 

pH, N-NH3 and VFA concentration in rumen fluid

Different forage sources in FMTRs did not affect the rumen pH at 0hrs and at 4 hrs after feeding (P>0.05). Similarly, N-NH3 and VFA were not significantly affected (P>0.05) by different forage sources in FTMRs (Table 3).

 

Ruminating behaviours

Ruminating behaviours (eating time, ruminating time and chewing time) were significantly affected (P<0.05) by different forage sources in FTMRs. However, forage sources in FMTRs did not significantly affect defecating frequency and urinating frequency (P>0.05). The forage sources in FTMRs significantly affected (P<0.05) eating rate, ruminating efficiency, chewing efficiency and feed value index (Table 4).

 

DISCUSSION

 

Results of the present study showed that, forage sources in FTMRs had no significant effects on the DM intake. This result was in agreement with Xu et al. (2014) and Mirzaei et al. (2018). In contrast, Ranathunga et al. (2010) reported that, different forage sources containing different levels of fibre characteristics result different DM intake. In our study, the forages used were chopped at 1-2 cm and naturally fermented with concentrate for at least 21 days before animal feeding, which can explain the present results. DM intake of cattle ranged from 2.29 to 2.67% of BW, which are in the range of the feed intake suggested

 

Table 2: Dry matter intake and nutrient digestibility of cattle fed different forage sources in fermented total mixed ration (FTMR).

 

Item	Treatments				SEM1	P
	FTMR 1	FTMR 2	FTMR 3	FTMR 4
Dry matter intake
kg/day	3.91	4.24	3.32	3.49	0.271	0.173
% Body weight	2.51	2.67	2.29	2.45	0.160	0.176
Digestibility (%)
Dry matter	63.1ab	66.8b	60.4a	67.4b	1.154	0.015
Organic matter	65.9ab	67.7bc	62.9a	69.3c	0.961	0.016
Crude protein	65.2	67.1	60.1	66.4	1.661	0.083
Neutral detergent fibre	51.1	52.6	51.7	54.4	2.210	0.744

 

1SEM: Standard error of the mean with df error = 6. a,b,c,d Values on the same row with different superscripts differ (P<0.05).

 

Table 3: pH, N-NH3 and VFA concentration in the rumen fluid of cattle fed different forage sources in fermented total mixed ration (FTMR).

 

Item	Treatments				SEM1	P
	FTMR 1	FTMR 2	FTMR 3	FTMR 4
pH at 0hrs	7.12	7.00	6.82	6.97	0.124	0.456
pH at 4hrs	6.60	6.90	6.88	6.63	0.141	0.374
N-NH3 at 0hrs (mg/dl)	7.11	6.76	7.56	7.11	0.471	0.702
N-NH3 at 4hrs (mg/dl)	12.89	7.60	12.51	10.78	2.133	0.364
VFAs at 0hrs (mmol)
Propionic	10.06	11.56	9.18	10.32	1.184	0.592
Acetic	32.64	32.53	31.68	34.89	6.245	0.985
Butyric	4.37	10.16	4.95	5.52	1.143	0.050
Acetic/propionic	3.22	2.73	3.39	3.49	0.502	0.725
VFAs at 4hrs (mmol)
Propionic	15.08	17.47	14.68	22.63	2.987	0.308
Acetic	38.73	43.90	42.06	62.47	7.444	0.208
Butyric	5.78	7.39	5.98	9.57	1.323	0.258
Acetic/propionic	2.57	2.51	2.86	2.76	0.455	0.987

 

1SEM: Standard error of the mean with df error = 6.

 

Table 4: Ruminating behaviors of cattle fed different forage sources in fermented total mixed ration (FTMR).

 

Item	Treatments				SEM1	P
	FTMR 1	FTMR 2	FTMR 3	FTMR 4
Eating time (min/d)	284.2a	222.2b	425.7c	310.7d	6.625	<0.001
Ruminating time (min/d)	294.0a	254.3a	442.5b	281.7a	16.43	0.001
Resting time (min/d)	861.8a	963.4b	571.5c	847.6a	16.99	<0.001
Total time (min/d)	1440	1440	1440	1440	-	-
Chewing time (min/d)	578.2a	476.6b	868.2c	592.4a	16.99	<0.001
Defecating frequency (no./d)	9.22	10.39	9.31	8.06	0.417	0.072
Urinating frequency (no./d)	16.11	9.05	13.59	14.94	3.120	0.415
Eating rate	827.0a	1151.2b	470.3c	677.3ac	62.58	0.001
Ruminating efficiency	795.5ab	1015.9b	456.7c	752.8a	72.44	0.009
Chewing efficiency	405.1a	534.5b	231.6c	356.2a	30.42	0.002
Feed value index (min/kg DM)	151.2a	112.5c	268.8c	170.9a	9.73	0.006

 

1SEM: Standard error of the mean with df error = 6. a,b,c,dValues on the same row with different superscripts differ (P< 0.05).

by Kearl (1982). These results indicate that cassava foliage, corn foliage, sugarcane leafy tops and elephant grass are good forage sources in FMTRs for ruminants.

 

The digestibilities of DM and OM were significantly different among forage sources in FMTRs, lowest in the FMTR with sugarcane leafy tops as forage and such results are in agreement with previous studies (Porter et al., 2007; Santos et al., 2011; Ozcan and Kilic, 2018). Porter et al. (2007) documented that, DM digestibility in animal fed a high NDF level in diets was lower than that in animal fed a low NDF level in diets. The FMTR with sugarcane leafy tops in the present study had NDF content higher than that in other FMTRs; this may explain the lower DM digestibility as well as lower DM intake. These observations are also in agreement with findings of Santos et al. (2011). However, these observations varied from other research of Castells et al. (2012), who reported that, DM and OM digestibilities were not affected by different forage sources. Similarly, Xu et al. (2014) recommended that, different forage sources did not affect DM and OM digestibilities. NDF digestibility was not significantly affected by forage sources in FMTRs, as per the finding of Castells et al. (2012). In contrast, Santos et al. (2011), Xu et al. (2014), De Souza et al. (2018) reported that, NDF digestibility was significantly affected by forage sources. Similarly, NDF and CP digestibilities also were not significantly affected by forage sources. This observation agrees with findings of Xu et al. (2014), who confirmed that forage sources did not affect CP digestibility. However, Castells et al. (2012), Santos et al. (2011) reported that different forage sources significantly affected CP digestibility. Based on above discussion, the effects of forage sources on the digestibility of nutrients varies, depending on factors such as forage types, chemical composition contents, processing methods and animal condition.

 

The pH value, N-NH3 and VFA concentration of the rumen fluid were not significantly affected by forage sources. These findings are consistent with previous studies, such as Eastridge et al. (2009) and Xu et al. (2014), who documented that, the rumen fermentation characteristics were not affected by the forage sources. Similarly, Mirzaei et al. (2018) reported that, rumen pH of calves was not significantly affected by forage sources, pH ranged from 5.94 to 5.97. Maktabi et al. (2016) observed similar ruminal pH levels in dairy calves fed finely ground starter feeds supplemented with different forage sources. In the present study, ruminal pH ranged from 6.82 to 7.12, which was sufficient for the maintenance of rumen function. NH3-N concentration in the rumen fluid of our study ranged from 6.76 to 12.89 mg/dL, apparently confirming McDonald et al. (1995) results, who concluded that optimal NH3-N concentration in the rumen fluid is above 5 mg/dL in order to improve the rumen ecology, microbial protein synthesis, digestibility and voluntary feed intake. The different forage sources did not affect individual VFA (acetic, propionic and butyric). This observation agrees with the finding of Xu et al. (2014). When rumen fermentation conditions are optimal, the acetate to propionate ratio should be greater than 2.1:1 (McDonald et al., 1995). In our study, acetate to propionate ratios were within the conditions of optimal fermentation.

 

Ruminating behaviours (eating time, ruminating time and chewing time) were significantly affected by different forage sources in FTMRs. Chewing time (eating time + ruminating time) was longest in the FMTR 3, which forage source is sugarcane leafy tops (868.2 min/d) and shortest in FTMR 2, which forage source is cassava foliage (476.6 min/d). Many previous researchers concluded that, eating time and chewing time of cattle were affected by particles of forage. Chewing time of cattle was longer when fed contained longer particles of the forage. In the present study, all forage was chopped 1-2 cm before mixing with concentrate then fermented for 21 days prior feeding the animal. Particles of forage sources in the present study could be similar. The significant difference of chewing time in the present study may be due to different NDF content in FTMRs. Beauchemin and Buchanan (1989), Lee et al. (2010) and Carlson et al. (2014) reported that, the higher the NDF content, the longer the ruminating time as well as chewing time. In present results, NDF content was higher in FTMR 3 than other treatments, and it is believed that this was what caused the longer chewing time. Chewing time in the present study was in the following order: FMTR 3>FTMR 4>FTMR 1>FMTR 2. For frequency of defecation and urination, there were no significant differences among treatments. Lee et al. (2010) recommended that, the more frequent defecation and urination in cattle fed more DM intake and more wet property of the diet. In the present study, DM intake of cattle and DM content in FTMRs were similar, which could be the cause for frequent defecation and urination in cattle was similar among treatments. Eating rate, ruminating efficiency and chewing efficiency were significantly affected by different forage sources in FMTR and were in the order of FTMR 2>FMTR 1>FMTR 4>FMTR 3. Schulze et al. (2014) concluded that, eating rate and chewing efficiency were significantly affected by NDF levels in diets. The different NDF contents in FMTRs in the present study contributed to different eating time, ruminating time and chewing time, these results would be the causative factors towards the different eating rate, ruminating and chewing efficiency. Feed value index was highest in FTMR 3, which forage source is sugarcane leafy tops and significant difference compared to other treatments. The difference of chewing time was causing of the different feed value index.

 

CONCLUSION

 

Different forage sources in FMTRs did not affect DM intake, digestibilities of CP and NDF and rumen characteristics. However, DM and OM digestibilities, ruminating behaviours, eating rate, ruminating and chewing efficiency were significantly affected by different forage sources in FMTRs. It could be recommended that, all forages in the present study should be used as ingredient in FMTRs for cattle in Vietnam.

ACKNOWLEDGMENTS

 

The authors thank the Mekong Basin Animal Research Network (MEKARN II) project for financially supporting this research.

 

Conflict of interest

 

The authors declare that they have no conflict of interest.

 

Authors Contribution

 

Writing the manuscript, designing experiments, Data collection, Data analyses: Dinh Van Dung.

Designing Experiments, Revising the manuscript, Data analyses: Le Dinh Phung.

Giving comments on the manuscript: Le Duc Ngoan

Giving comments on the manuscript: Nguyen Xuan Ba.

Giving comments on the manuscript: Nguyen Huu Van.

Giving comments on the manuscript: Le Duc Thao.

 

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