Bali Heifers Performance on Cassava Leaves, Palm Oil Sludge and Yeast Supplementation in a Ration Based on Kumpai Grass ( Hymenachne amplexicaulis (Rudge) Nees )

| Utilization of potential swamp forages, by-product of the palm oil industry, and cassava is a strategy in the improvement of cattle feed. The purpose of this study was to evaluate the effect of cassava leaves, palm oil sludge, and yeast supplementation on a ration based on Kumpai grass ( Hymenachne amplexicaulis ( Rudge ) Nees ) on the performance of Bali heifers. Twelve Bali heifers were allocated into two groups. First group was fed with control diet consisting of 70% Kumpai grass + 30% concentrate (R0) while second group (R1) was fed a diet consisting of 55% Kumpai grass + 15% concentrate + 15% palm oil sludge (POS) + 15% cassava leaves + 5 g yeast ( Saccharomyces cerevisiae )/head/d. The variables measured in this study were intake, digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber , average daily gain, feed conversion ratio, and farmer income. Data were analyzed by independent t-test. The results showed that the supplemented diet had a significant performance by improving the intake of dry matter, organic matter, and crude protein. Moreover, it also followed by increasing the digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber, average daily gain, feed conversion ratio, and farmer income. Supplementation of palm oil sludge, cassava leaves, and yeast in the Kumpai grass-based ration significantly increased the performance of Bali heifers. Heifers fed the supplements gave a higher income than those without supplements.


INTRODUCTION
I n the non-tidal swamp of South Sumatra, the forage supply mainly depends on aquatic vegetations, one of them is Kumpai grass (Hymenachne amplexicaulis (Rudge) Nees). However, the utilization of Kumpai grass is limited by the high fiber fraction that may reduce intake and digestibility when fed alone in the diet (Ali et al., 2013;Rostini et al., 2014).
The high price of concentrate was the main reason for the low frequency of cattle supplementation by smallholder farmers (Hernaman et al., 2018;Mumba et al., 2018). Concerning the price of commercial concentrate, the locally-available concentrate may increase cattle performances and farmer income. Palm oil sludge (POS) is one of the agro-industrial by-products from palm oil processing at a low price and available for small scale farming. The supplementation of POS has a potency for increasing intake and cattle performance due to a higher content of water-soluble carbohydrates and a source of unsaturated fatty acids (Hayyan et al., 2010) that might reduce methane gas production (Machmüller et al., 2000;Vlaeminck et al., 2006). An often-used approach for boosting cattle production in humid tropical areas was cassava leaves since a higher crude protein (CP) content, especially branched amino acids. Furthermore, The addition of branched amino acids in the ration was able to increase

Advances in Animal and Veterinary Sciences
September 2020 | Volume 8 | Issue 8 | Page 814 the growth of cellulolytic bacteria. It could be reflected by increasing the digestibility of dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) (Puastuti et al., 2017;Tedeschi et al., 2015).

Supplementation of yeast (Saccharomyces cerevisiae)
increased the population of cellulolytic bacteria and reduced the accumulation of lactic acid and oxygen concentration in the rumen and thus increased the use of starch in the ration (Kumar et al., 2013;Pinloche et al., 2013). Other studies proved that yeast supplementation increased the digestibility of DM, OM, CP, and fiber fraction and microbial efficiency Tang et al., 2008). The purpose of this study was to evaluate the effect of the locally-available supplementations on Bali heifer's performances.

Location and duRation
This research was conducted in the village of Tanjung Seteko, Ogan Ilir district, South Sumatra province of Indonesia, Rubber and oil palm plantations are dominantly cultivated in this area and serves a potential source of feed for beef cattle originating from the plantations by-products. The study was conducted for four months.

ExpERimEntaL dEsign and animaLs
Twelve Bali heifers aged one year with an initial body weight of 151±12.3 kg (mean±standard deviation) were randomly allocated into two experimental treatments. The animals were placed in individual pens (1.6 m x 2.5 m).
The trial was conducted for seven weeks and consisted of two weeks of preliminary period, four weeks of the adaptation period, and one week of digestibility measurement when feed intake and fecal excretion were quantified. Live weight was measured weekly before morning feeding.

fEEding
The experimental treatments comprised of two diets. The first group was the control diet (R0) consisting of Kumpai grass and concentrate (70:30, DM basis), the second group (R1) consisted of Kumpai grass, cassava leaves, POS (Palm oil sludge), and concentrate (55:15:15:15) and 5 g yeast/ head/day ( Table 2). The ration was prepared according to NRC (2001) for small breed cattle with estimated DM intake of 3% body weight.
Kumpai grass and cassava leaves were collected in the evening and then chaffed to ±10 cm. Palm oil sludge was obtained from a palm oil processing while Yeast (Yea-sac) was obtained from Livestock Research Center at Ciawi, Bogor. Feeding was started at 8.00 AM. First, the concentrate (yeast) and POS were offered while grass and cassava leaves were offered at 10:00 AM and 4:00 PM. Animals had free access to drinking water and Salt-mineral lick.

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Quantification of fEEd intakE and fEcEs ExcREtion
Samples of 100 g of fresh material (FM) consisting of Kumpai grass, cassava leaves, POS, and concentrates were daily collected during the week of digestibility measurement. After that, to determine the diet-digestibility, the feed offered and refusal were weighed and recorded per animal per day. No concentrate refusal was found. The samples were dried at 65 o C for 72 hours and then pooled at the end of each trial week in order to obtain 100 g of dried sample.
Determination of daily fecal excretion was carried by removing the feces each time the animals defecated from the clean floor throughout the digestion week. For each heifer and every 24 hours (8:00 AM), all fesses were collected into a 10-l bucket and weighed. After that, the fesses were mixed by hand, and a sample of 300 g FM was dried in an aluminum foil tray at 65 ° C for 72 hours and re-weighed. At the end of the trial, all dry samples were grounded to pass a 1-mm mesh. Subsamples of 100 g of dried feces were stored for analysis.

cHEmicaL anaLysis of sampLEs
Samples from Kumpai grass, cassava leaves, POS and concentrates as well as fecal samples were analyzed for DM and ash (AOAC, 2005), neutral detergent fiber (NDF), and acid detergent fiber (ADF) (Van Soest et al., 1991). The concentration of N was determined by the Kjeldahl procedure (AOAC, 2005) using the distillation unit Tecator 1028 (Tecator GmbH; Hagen, Germany). All analyzes were carried out in duplicate, and the analyzes were repeated when the results differed by more than 5%.

data anaLysis
Digestibility value was obtained by reducing the intake of the dietary nutrient with nutrients in the feces and then divided by the intake of dietary nutrition. The feed conversion ratio was calculated by dividing the DM intake by live weight gain. Income over feed cost was calculated based on the differences between the selling price of the Bali heifers gain and feed costs in the unit of Indonesian rupiah (IDR). Differences in observed parameters between groups of treatments were analyzed by the t-test (SPSS 13.0 program).

RESULTS AND DISCUSSION
The results showed that the supplemented R1 ration increased intake (P<0.05) of DM, OM, and CP, whereas NDF and ADF were not significantly. increased intake for DM 13.07%, OM 21.34%, and CP 102.1% (Table 3). Furthermore, it also followed by increasing the digestibility of DM (16.21%), OM (18.66%), CP (24.12%), NDF (8.81%), and ADF (13.30%) compared without supplement (P<0.05) ( Table 4).  The difference value of DM intake was caused by the nutrients, especially protein and energy feed (McDonald et al., 2010). The higher intake might relate to the lower content of NDF and higher CP in the supplemented diet, which is consistent with Cunningham et al. (2005) that the lower NDF content, the higher the feed intakes. Coleman and Moore (2003) stated that regulation of intake was an interaction between the characteristics of feed and the animal where mainly depend on rumen capacity and passage rate (McDonald et al., 2010). Increased DM, OM, and CP in the R1 were due by cassava leaves to have high CP content and also by POS as a source of fatty acids so that it will contribute to the preference level (palatability) cattle on feed intake. The same result was reported by Sanh et al. (2002) stated that the palatability and digestibility of nutrients feed were related to the CP content. According to NRC (2001), generally, the additional calcium salts of fatty acids in dairy cows can reduce the consumption of

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September 2020 | Volume 8 | Issue 8 | Page 816 DM. It is assumed that yeast supplementation modified the condition of the rumen, so the effects of unsaturated fatty acids on the DM intake could be suppressed.
The higher digestibility values might vary due to the lower fiber fraction of NDF and ADF and the higher CP contents of supplemented ration (Table 4). This result is due to the potential work of the carbon framework from sources of POS and N cassava leaves. It increases microbial growth in the rumen so that the microbial population will increase and continue to increase ration degradation in the rumen. Branched chain amino acids of cassava leaves (Table 1) might contribute to the higher NDF, and ADF digestibility since these amino acids are sources of carbon framework for rumen microbial growth (Puastuti et al., 2017;Tedeschi et al., 2015;Zhang et al., 2011). Increased protein supplementation has a positive correlation effect on CP digestibility with increased digestibility of DM and OM (Figueiras et al., 2016). The supplementation of cassava leaves (for branch chain amino acid (BCAA) source) and organic minerals in palm oil-based waste ration can increase the digestibility value of DM, OM, and Average daily gain (ADG) (Adhianto et al., 2018).
Souze et al. (2010) and Larazzarini et al. (2016) reported that nutrient supplementation both energy and protein together could be optimized for microbial growth in order to use fibrous feed and will increase the value of intake and digestibility. Moreover, it will increase nutrients for the formation of body tissues. Badarina et al. (2017) showed that the feeding of POS and some local fermented feed ingredients up to 10 kg/d increased the DM intake by 5.78 kg and digestibility of the ration by 73.14%. These results might also relate to the improvement of digestibility by yeast supplementation in the R1 ration Tang et al., 2008). Supplementation of yeast increased the population of cellulolytic bacteria and reduced the accumulation of lactic acid and oxygen concentration in the rumen and thus increased the use of starch in the ration (Kumar et al., 2013;Pinloche et al., 2013).
The results showed that the mean of ADG of the heifers on the supplemented diet (R1) was higher (P<0.05) than that on the control diet (R0). As a result, the supplemented diet had a better FCR compared to the control diet (Table 5). Bali heifers fed POS, cassava leaves, and yeast supplementation gave 489% higher IOFC values than those fed Kumpai grass and concentrated (Table 6).
A bodyweight gain of cattle is strongly associated with nutrition in the feed and the feed digestibility level.
Rations have a high nutrient content, and good palatability level can quickly increase body weight gain of cattle for fattening (Purwanti et al., 2014). According to NRC (2001), body weight gain is influenced by several factors such as total protein obtained each day, type of animal, age, state of genetic, environmental conditions, the condition of each individual, and the treatment of management.  The increase of ADG is caused by an increase in the consumption and nutrient digestibility of the treatment ration. The result of the present study is in line with  that the supplementation of Lamtoro leaves (Leucaena leucocephala (Lam.) de Wit) in the fermented Kumpai grass-based diet, which the results showed a higher ADG of Bali bulls than those on fermented Kumpai grass alone. The addition of yeast as a feed supplement in the diet has the potential to improve the rumen ecosystem, thus contributing to improved rumen microbial population. The increase in the digestibility and feed intake will increase nutrients to the body's tissue (Tripathi and Karim, 2010).
The conversion rate is the ratio between the amount of DM intake and animal body weight gain (Katongole et al., 2009). The value of feed conversion is highly dependent on the digestibility and nutrient metabolism in the body. Feed consumed will be used for basic living and production. Feed conversion value depends on the quality of feed, the higher nutrient contained, the better the resulting feed