Abstract
Abstract -This research's objective was to determine the dietary rumen degradability and growth performances of goats
I. INTRODUCTION
Farmers use high proportion of concentrates in the ration to accelerate the growth and production of ruminants. Although it has a positive impact on productivity, the use of excessive concentrate will lead to an increased production cost. Approximately 60% of the cost of production can be attributed to the concentrates fed to the animals (Chantaprasarn and Wanapat, 2008) .
I. INTRODUCTION
Nutrients are needed for the maintenance and production of animals. Aside from crude protein (CP), energy and minerals, the content of neutral detergent fiber (NDF) in the feed ration should also be considered. The sources for NDF are concentrates and forage. The proportion of forage NDF in the ration also plays a role in ruminant productivity. It is associated with chewing activity, saliva production, fermentation rate and yield, and digestibility of feed. Chewing time is highly influenced by NDF content, rather than with the particle size (PS) of forage (Beachemin, 1991 cited by Moon et al., 2004) . Feed rations with sufficient NDF content from roughages or forage can be given to dairy animals to maximize production and maintain health by sustaining a stable environment in the rumen (Tafaj et al., 2005) .
I. INTRODUCTION
The level and ratio of NDF in the diet can be used as standard to formulate proportion of forage and concentrate in the diets. With the optimized value of NDF, it can improve the performance of ruminant. In general, optimizing forage as source of NDF will indirectly decrease production costs while increasing revenue without reducing the quality and quantity of production. Theoretically, the value of NDF from forage is more useful by around 50% than concentrates (NRC, 2001 ). The ratio of forage and concentrate of the diet should contain around 75% forage NDF but in temperate regions, the minimum NDF level is around 25% to 28%. Because of the poor quality of forage in the tropics, this recommended NDF level is relatively difficult to maintain. A minimum of dietary NDF level (25%) and proportion of forage NDF (75% to 60%) in the diet still provides sufficient utilization of fiber for production and maintains fat corrected milk (Kanjanapruthipong et al., 2001 ).
I. INTRODUCTION
Level of ruminant productivity is sensitive to dietary NDF level. High producing ruminants require NDF level of approximately 32% while animal with low productivity will require 44% of the ration (NRC, 2001) . It is important to observe and evaluate the impacts of forage NDF in the diets as recommended by NRC, with some adjustments based on the tropical condition and practical conditions in the farm. The main objective of this research is to determine the ratio of NDF from forage and concentrate for optimum dietary rumen degradability and growth performances of Philippine native goats.
II. MATERIAL AND METHOD

Experimental Animals
Eighteen (18) native female goats were grouped into 6 weight classes for the feeding trial following a randomized complete block design (RCBD). The average body weight (BW) of the animals was around 7.96 ± 2.21 kg (CV = 27.76%) and were approximately 1 year of age. For in situ digestibility, three (3) male of mature goats were composed following latin square design (LSD), that were surgically fitted with cannulated rumen.
Experimental and Treatments Design
The dietary treatments were composed of P. purpureum as source of forage, commercial concentrate mixture, urea and molasses. The nutrient composition of P. purpureum and a commercial concentrate mixture used in the experiment is shown in Table 1 . The ratios of NDF from forage and concentrate were calculated based on the total amount of NDF supplied by forage and concentrate portions. The proportion of NDF from forage and concentrate in the diets are shown in Table 2 . The different dietary NDF ratios were attained by adjusting the forage to concentrate ratio based on the formulation in Table  3 . The dietary nutrient content of the treatments are shown in Table 4 . The dietary crude protein (13.71±0.14%) and total digestible nutrients (TDN) (66.61±4.81%) used in studies 1 and 2 were formulated to be equal between the treatments. The diets were adjusted to be isocaloric and isonitrogenous by using urea and molasses. TDN content of P. purpureum (NP), mixed concentrates 1, 2, and 3 were estimated using the formulation used by Sutardi (2001) and converted based on the total amount of TDN on digestibility study. Notes: NP : Napier grass or Pennicetum purpureum; C1: Concentrate was mixed with urea and molasses based on treatment 1; C2: Concentrate was mixed with urea and molasses based on treatment 2; C3: Concentrate was mixed with urea and molasses based on treatment 3; D1: Napier was mixed with mixed concentrate based on treatment 1; D2: Napier was mixed with mixed concentrate based on treatment 2; D3: Napier was mixed with mixed concentrate based on treatment 3; 1 : TDN value based on the equation from Sutardi (2001).
Experimental and Treatments Design
Research procedures feeding trial: The adaptation period of the animals to the environment and ration consisted of 7 days. On the second day, the goats were placed in their respective cages based on the weight of group (6 groups) as a blocking factor then the goats within each group were randomly assigned to 3 treatments. At this stage, the ability of goat for consuming feed was observed. At the end of the preliminary stage, goats were first weighed to obtain initial body weight and were weighed weekly during the experiment. Treatment diets were given at 3% of body weight. The goats were fed three times a day: morning (8:00 and 11:00 am) and afternoon (3:00 pm). Concentrates were fed first, followed by feeding of forages one hour after. Drinking water was provided ad libitum. Nutrient contents of dietary treatments were analyzed for proximate and NDF analysis following standard methods (AOAC, 1984 , Van Soest et al., 1991 .
Experimental and Treatments Design
Research procedures in situ study: Approximately 2 g of the diet was weighed in duplicate into nylon bags as described by Ørskov et al. (1980) ; Isah and Babyemi (2010) . The bags were 5x13 cm in size, with a pore size of 41 μm. The bags were inserted via permanent ruminal cannulae in 3 male goats and left in the rumen for 3, 6, 12, 24, 36, or 48 hours. At the end of the incubation period, all bags were withdrawn at the same time (Osuji et al., 1993; Isah and Babyemi, 2010) . The animals were fed with Napier grass (Pennisetum purpureum) at 7:00 am, 11:00 am, and 3:00 pm for ad libitum. The animals are also supplied with ad libitum fresh and clean water.
Experimental and Treatments Design
After finishing incubation, bags were washed under running cold water until the rinse water got clear and then dried in an oven for 48 hours at 105°C. Determination of washing loss at zero time (incubation at 0 hour) was carried out by soaking two of the bags containing each of the samples in tap water for 1 hour. The dry bags were weighed and DM loss was calculated.
Experimental and Treatments Design
Disappearance was calculated using the formulation stated by Osuji et al (1993) , Disappearance = The data were analyzed using ANOVA. Treatment mean differences were tested using Tukey's method with error level (α) of 5% (Gaspersz, 1991) . The MINITAB 14 was used for running the analysis of variance and Tukey's test for other analyses, if necessary.
III. RESULT AND DISCUSSION

In Situ Degradability
Dry matter degradability at 0 hour, or degradability caused by the washed nylon bag is shown in Table 5 . Treatments 1, 2, and 3 did not significantly affect the rate of degradability of dry matter at 0 hours (p>0.05). The average dry matter degradability at 0 hours, at T1, T2 and T3 were 30.98, 29.01 and 29.38%, respectively.
In Situ Degradability
Levels of b or potentially degradable fraction of dry matter degradability on each treatment showed no significant difference (p>0.05). This indicates that the potentially degradable fraction of each treatment was relatively the same. The mean of potentially degradable fraction in Treatments 1, 2, and 3, were 36.63, 53.56 and 44.08%, respectively. Data on the rate of degradation of b in this experiment was relatively the same. Effect of different NDF ratios in the diets showed no significant effect on the rate of degradation of b (p>0.05). The mean of the rates of degradation of b from each treatment were 0.05, 0.03 and 0.05, respectively.
In Situ Degradability
In this case, the rate of degradability diet treatment when seen from the data a, b and c with the parameters showed no differences in dry matter. If the same passage in the rumen was assumed, the rate of feed utilization and value of feed utilization by the rumen microbes were relatively similar. Comparing with the results of the study of Morais (2012) , dry matter degradability in this experiment was higher than the samples of rain tree (0-100% from the diets) mixed with rice bran and copra meal. In his experiment, the average value of a was around 45.44%, b was 22.78% and c was around 0.07. In this present study, the value of a was 29.84%, b was 47.83%, and c was 0.04. Results of this study also descriptively showed that Treatment 2 had higher degradability compared to Treatments 3 and 1. The values were estimated using 48 hours as time of incubation with the result of DM degradability in Morais (2012) at around 67.43% compared with 70.66% found in this experiment.
In Situ Degradability
Similar levels of DM degradability in rumen in each treatment were probably caused by similar levels of NDF diets. Yulistiani et al. (2008) stated that the level of NDF diet affects DM degradability in the rumen and lower NDF diet results to higher DM degradability. If the result of dietary degradability in this experiment is compared with the P. purpureum that was cited by Januarti (2009), where P. purpureum was found to incubate during maximum time in rumen and had dry matter degradability of around 37.18%, the dietary DM degradability was higher (70.66%) during 48 hours incubation in this experiment. Wati et al. (2012) mentioned that results of other studies on P. purpureum degradability showed a range of only 49.10% during 48 hours incubation. This indicates that the higher DM degradability on dietary treatments was caused by lower content of NDF diets than P. purpureum in this study (Hartadi et al., 2005; Januarti , 2009; Wati et al., 2012 and Yulistiani et al., 2008) .
In Situ Degradability
Different ratios of NDF from forage and concentrate in the diets used in this experiment did not affect the degradability of CP among the diets in 0 hours, potential degradability fraction of CP or b, and rate of degradation of b (p>0.05). Data on CP degradability of each treatment are shown in Table 5 . This statement reinforces the claim that the capacity to digest the feed in the rumen is relatively the same on every treatment, and that the rate of degradability of CP in the diets is relatively equal and linear with degradability of DM and NDF diets, indicating no difference.
In Situ Degradability
Degradability of CP diets on 0 hours were 43.33, 44.44 and 46.50%, respectively from Treatments 1, 2, and 3; whereas potentially degradable fractions of CP diets or b were 34.16% for Treatment 1, 32.39% for Treatment 2, and for Treatment 3 at around 43.30%. According to descriptive analysis, the highest rate of CP degradation of b in this experiment was on Treatment 1 at around 0.04 while Treatments 2 and 3 were in the similar level of around 0.03. Terramoccia et al. (2000) reported the CP degradability of concentrate on in sacco study has a value of around 19.3% for a, around 60% for b, and around 0.120/h for c. Compared with the study results by Morais (2012) , CP degradability in this experiment was higher than the samples of rain tree (0-100% from the diets) mixed with rice bran and copra meal. In the experiment of Morais (2012) , the time of incubation equals with 48 hours. The degradability of CP in this experiment was around 73.70% compared with his experiment which had a degradability of CP of around 66.60%. It means that the ratios of forage and concentrate in the diets used in this experiment were more effectively fermented in the rumen compared with the diets used by Morais (2012) .
Feeding Trial
Different treatments were represented by the different ratios of neutral detergent fiber (NDF) from forage and concentrate in the diet. The data on dry matter (DM) intake (forage, concentrate and total intake), crude protein (CP) intake (forage, concentrate and total intake), NDF intake (forage, concentrate and total intake) and the ratio of forage in diets are shown in Table 5 .
Feeding Trial
Treatments based on the different ratios of NDF from forage and concentrate in the diet caused the intake rate of forage and concentrates on the DM, CP and NDF to be significantly different (p<0.05). However, the total intake of DM, CP and NDF were not significantly affected by differences in the ratios of NDF from forage and concentrate in the diets (P>0.05).
Feeding Trial
Dry matter intake (DMI) of forage in Treatment The data from forage and concentrate intake were converted to a ratio of forage in diets. Thus, the ratio of forage intake in the total intake or diets was higher in Treatment 1 (67.89%), while Treatment 2 had only a ratio of 60.48% while the lowest ratio was found in Treatment 3 (53.62%).
Feeding Trial
From the data above, it could be concluded that the quality of the diets in each treatment was relatively the same because the total intake of DM and their nutritional contents were relatively similar. It could also be assumed the diets used in this experiment had almost the same palatability. Feeds with good quality are usually consumed by animals in larger quantities compared to low-quality feed (Tillman et al., 1984) . The diets were formulated to contain the same amount of CP and energy based on the nutrient requirement of the animals. The content of NDF has been reported to affect the level of consumption through physical effects (filling effect) so it can be used as a variable in predicting consumption (Waldo, 1986; Merten, 1994) . The results of the study of Coleman et al. (1999) also showed that the content of NDF and lignin accounted for only 56% of the variability in the amount of forage consumption studied. It is possible that the NDF content in this experiment of around 58.94 to 60.65% was of the same level and was not able to influence the total consumption of nutrients.
Feeding Trial
From the performance of native goats given 3 kinds of diets with different ratios of NDF form forage and concentrate, average daily gain (ADG), feed conversion ratio (FCR), feed cost and feed cost per gain can be seen in Table 5 . It is an important aspect to be considered, whether the treatments can be used to indicate significant differences in economic terms.
Feeding Trial
Differences in the ratios of NDF from forage and concentrate in the diets did not significantly affect the performance of the native goats (p>0.05). The mean ADG in Treatments 1, 2, and 3 were 12.24, 11.43 and 17.69 g/d, respectively. The mean of FCR in Treatments 1, 2, and 3 were relatively similar, ranging from 25.26, 18.91 and 16.50. Weight gain of goats is sensitive to protein and energy content of forages (Ash and Norton, 1987) . In contrast to the results of Haddad (2005) , a linear increase was observed for ADG with increasing levels of dietary concentrates. Dønnem et al. (2011) reported that Norwegian dairy goats supplemented with a low (LC; 0.6 kg per goat daily) or normal (NC; 1.2 kg per goat daily) level of concentrate, had a body gain of around 25 vs 94 g during their experiment. In this present study, increasing the portion of concentrate did not affect the ADG of the goats. This was also supported by the equal DMI and total nutrients intake found between the treatments.
Feeding Trial
Economically, feed cost was cheaper in Treatment 1 (2.45 PHP/d), followed by Treatment 2 at a cost of 2.76 PHP/d, and the most expensive maintenance cost was contained in Treatment 3 which was equal to 3.11 PHP/d. However, feed cost per gain in each treatment had relatively the same sawyerjody@example.net, 0.24 and 0.23 PHP/g, respectively, in Treatments 1, 2, and 3. This result has a different pattern from Haddad (2005) who stated that kids fed with more proportion of concentrate had the lowest FCR than the kids fed with higher proportion of forage. Kids fed with the low forage (LF) diet had a lower feed to gain ratio (3.4) compared with kids fed with the medium to high forage (MHF) and medium to low forage (MLF) diet (average = 5.2). Kids fed the high forage (HF) diet had the highest feed to gain ratio (7.4) . But in contrast with Haddad (2005) , the result of feed cost as found in this experiment was reduced by increasing the levels of concentrates. Dietary treatment used in this experiment was more effective than the diets that were used by Morais (2012) which had a FCR of only around 22.54.
Feeding Trial
The ADG of 13.92 g/d obtained in this study indicates lower DMI of around 73.71 g/d and a shortage of TDN of around 7.59 g/d based on the nutritional requirement compiled by Kearl (1982) . There was a surplus, however, at around 6.38 g/d for digestible protein. This indicates that tropical animals will require more energy and protein for maintenance based on the nutrition table for ruminants in temperate zone compiled by Kearl (1982) . It is possible that the requirement for energy as TDN was supplied by the excess in digestible protein that was converted to energy from transformation of protein.
Feeding Trial
IV. CONCLUSION Based on the interpretation of the data obtained in this study, different ratios of NDF in the diets had no effect on dry matter, crude protein, and NDF intake. This was supported by dietary rumen degradability, which was the same among treatments. Feed intake of the different diets did not significantly affect the performance of native goats with an average ADG of 13.92 g/d and FC of native goats worth 20.30. Giving higher proportion of NDF concentrate based on the ratio of NDF in the diets had a higher production cost than other diets prepared with greater proportion of forage NDF. It had the same efficiency in feed cost per gain worth 0.25 PHP/g. This means that NDF from forage of 72% in the diets had the same feed utilization and growth performance when compared to NDF from forage of around 64% to 57% in the diets using higher portion of concentrate.

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