Growth of Bali bulls fattened with Leucaena leucocephala in Sumbawa , Eastern Indonesia

The contribution of West Nusa Tenggara Province to domestic beef supply in Indonesia is relatively small; however, beef cattle are very important for the livelihoods of smallholder farmers in the region. Bali cattle (Bos javanicus) are the predominant breed, as they are adapted to harsh nutritional conditions, are highly fertile and have low calf mortality (Toelihere 2003). While these cattle are genetically capable of achieving a growth rate of 0.85 kg/d (Mastika 2003), this is rarely achieved as poor nutrition is a severe limitation to animal growth in traditional village systems (Panjaitan 2012). Improving feed quality and supply is vital to increasing growth rates and product quality. Forage tree legumes such as leucaena (Leucaena leucocephala) offer the best chance of providing high quality feed to fatten Bali bulls in village systems, where leucaena is well-adapted. Leucaena has been fed for about 2 decades in Sumbawa district of West Nusa Tenggara, although the practice is limited to specific villages, mostly Balinese, even though farmers nearby have similar biophysical conditions and livestock nutrition problems. The objective of this work was to document the practices employed by farmers in Sumbawa to maximize growth rates by feeding leucaena, so that their detailed knowledge can be passed onto other villagers in a pilot roll-out program (Kana Hau 2014).


Introduction
The contribution of West Nusa Tenggara Province to domestic beef supply in Indonesia is relatively small; however, beef cattle are very important for the livelihoods of smallholder farmers in the region.Bali cattle (Bos javanicus) are the predominant breed, as they are adapted to harsh nutritional conditions, are highly fertile and have low calf mortality (Toelihere 2003).While these cattle are genetically capable of achieving a growth rate of 0.85 kg/d (Mastika 2003), this is rarely achieved as poor nutrition is a severe limitation to animal growth in traditional village systems (Panjaitan 2012).Improving feed quality and supply is vital to increasing growth rates and product quality.Forage tree legumes such as leucaena (Leucaena leucocephala) offer the best chance of providing high quality feed to fatten Bali bulls in village systems, where leucaena is well-adapted.Leucaena has been fed for about 2 decades in Sumbawa district of West Nusa Tenggara, although the practice is limited to specific villages, mostly Balinese, even though farmers nearby have similar biophysical conditions and livestock nutrition problems.
The objective of this work was to document the practices employed by farmers in Sumbawa to maximize growth rates by feeding leucaena, so that their detailed knowledge can be passed onto other villagers in a pilot roll-out program (Kana Hau 2014).

Materials and Methods
The study was conducted from April 2012 to March 2013 with 21 farmers in the hamlet of Jatisari in ___________ Correspondence: Tanda Panjaitan, Assessment Institute for Agricultural Technology − NTB, Mataram, Lombok, NTB 83371, Indonesia.Email: tanda_panjaitan@yahoo.comSumbawa district of Nusa Tenggara Province, Indonesia, which has an annual rainfall of 865 ± 246 mm, mostly falling between November and May.Bull fattening in Jatisari is based on feeding high leucaena diets in a cutand-carry system to animals tethered in simple sheds (roof, cement floor, feed bunker but no side walls).Farmers' norm0al management and trading practices result in constantly changing numbers of bulls being fattened.Parameters monitored included average daily gain (ADG), feed offered including amount of leucaena in the diet and sale weight.All cattle were weighed each month following overnight fasting (feed and water).Fresh feed offered was determined over 3 consecutive days each month.Bulls were treated with albendazole to control internal parasites prior to being fattened and were sprayed regularly with deltamethrin to control external parasites.

Results and Discussion
In general, farmers had 3 fattening periods each year.The average fattening period was 127 ± 58 days; the shortest and the longest fattening periods were 37 and 296 days, respectively.The number of bulls purchased and fattened during the wet season was more than twice that of the dry months, due to increased feed resources available.The initial weight of bulls varied within and between farms with an average of 191 ± 41 kg at 18 ± 7 months of age; the lightest and heaviest initial weights were 97 and 277 kg, respectively.Farmers with younger cattle had a longer fattening period.The average sale weight of bulls was 229 ± 27 kg, while the lowest and the highest were 188 and 318 kg, respectively.Average sale weight was thus well below the accepted standard for slaughtering beef (300 kg).This low sale weight may contribute to the low dressing percentages commonly stated by traders and butchers in the region.
There was no overall pattern of animal sales, which was generally based on the need for money, rather than on optimal bull parameters.Increasing sale weight by delaying sale time and extending the fattening period may be an option to not only increase dressing percentage but also obtain premium prices.The ADG over the 11 months was 0.42 ± 0.12 kg/d.The highest average point of 0.61 kg/d was obtained early in the dry season in June, while the lowest average point of 0.23 kg/d occurred at the end of the dry season in October (Table 1).However, bulls belonging to the best farmers achieved ADGs of 0.83 kg/d over the 11-month period including ADGs of ≥1 kg/d for May, June and August.As most bulls were under-nourished on arrival, the highest ADGs were achieved in the initial month due to compensatory weight gain.
It was not possible to determine the precise amount of feed consumed, as dry matter content could not be calculated and refusals varied according to the stemminess of the leucaena branches being fed.Nevertheless, the highest amount of fresh feed offered was at the end of the wet season in May, while the lowest offer occurred in the dry season between August and October.The average percentage of leucaena in diets over the year was approximately 80%, followed by corn straw 13% and native grass 7%.The percentage of leucaena in the diet was highest (100%) between May and July, and lowest (approximately 50%) in October.
The overall average daily gain recorded for all Bali bulls over the measurement period (0.42 kg/d) was 60% more than that achieved under the traditional system (0.26 kg/d) (Panjaitan 2012).It was similar to the 0.44 kg/d reported for other improved feeding systems by Mastika (2003), but only half the potential growth rate of Bali bulls (0.85 kg/d) also reported by Mastika (2003).This was most likely due to an insufficient amount of feed offered, especially during the dry season, as the best ADGs (0.56−0.61 kg/d) were recorded in the wetter months of May, June and January, when feed supply and percentage leucaena in the diets were highest (close to 100%).Significantly, the best farmers achieved maximum weight gains ≥0.8 kg/d for 6 of the 11 months, close to the genetic potential of Bali bulls reported by Mastika (2003).Further monitoring is planned to understand the practices of the best farmers.

Conclusions
It is concluded that increasing supply of leucaena, either by planting more leucaena or altering the number of bulls to fit available feed supply, will increase growth rates to near the potential for Bali bulls.This will enable smallholders to more quickly achieve the appropriate sale weight of 300 kg.
Wider adoption of the feeding and management strategies employed by the best farmers of Jatisari provides an excellent opportunity to increase the output of fattened bulls from other smallholders in other regions of West Nusa Tenggara and East Nusa Tenggara.Achieving this potential will require not only a thorough knowledge of leucaena establishment, improved management, housing and hygiene of the bulls, but also an understanding of the barriers to adoption.It will require "an effective outreach strategy to address perceptions, access and regulations that are barriers to implementation of the innovations.The outreach strategy will need to be comprehensive, long term, and involve multiple stakeholders" (Kana Hau 2014).

Table 1 .
Average daily gains (±s.e.) and weights of 276 Bali bulls fattened on leucaena under a smallholder cut-and-carry system between May 2012 and March 2013 in Sumbawa, Indonesia.