The Estimation of Growth Curve of Bali Cattle at Bone and Barru Districts, South Sulawesi, Indonesia Using Ten Body Measurements

The estimation of growth curves and mature size of ten body measurements, namely withers height,hip height, body length, chest girth, chest depth, chest width, rump length, hip width, thurl width, andpin bone width, were studied in Bali bulls and heifers at the age of 12, 15, 18, 21 and 24 months. 108bulls and 146 heifers at Bone district and 152 bulls and 110 heifers at Barru district, South Sulawesi,Indonesia were measured. The Brody growth function was fitted to each animal's records and leastsquaresanalysis were used to investigate the effects of place, sex, and age to growth curve and maturesize of body measurements of Bali bulls and heifers. The result showed that the growth of bodymeasurements of Bali cattle until 24 months of age were still increasing and not reaching the mature sizeyet. The place, sex and age factors were significantly affected to the growth of body measurements ofBali cattle.


INTRODUCTION
Bali cattle (Bos sondaicus, Bos javanicus, bos/Bibos banteng) is one of the genetic resources of indigenous Indonesian livestock and also one of important beef cattle breed that contribute to the development of livestock industry in Indonesia. Bali cattle dominates the beef cattle population primarily in eastern of Indonesia such as East and West Nusa Tenggara islands and South Sulawesi. Chamdi (2005) indicated that Bali cattle has superiorities in some aspects such as high fertility rate, high production performance, high adaptation capability, good beef performance traits, high innate resistance to ticks and tick-borne diseases, good ability to rapidly recover condition after poor usage, and good work capability. Majority of the Bali cattle farmers in Indonesia raise their Bali cattle under three management systems such as grazing on open lands, grazing within plantations, and intensive cut and carry management with animals held in separate individual animal housing  beside that the farmers do not give special attention for the quality and quantity of feeding.
The measurements of cattle's body measurements are widely used for genetic improvements of meat production in live beef cattle because it could help the breeder to recognize the early and late maturing animals of different sizes and to evaluate growth performance of farm animals. Cattle's body measurement affects efficiency, maintenance requirements, cattle's profitability, reproduction, and cull cattle value. The characterization of some body measurements of beef cattle related to the growth will lead to a more efficient utilization of these important genetic resources. Therefore mature size, which is estimated by growth curve of body measurement, impacts the profitability of beef enterprises and thus should be considered in selection programs (Marco et al., 2010). Information regarding the growth curve of body measurements of Bali cattle is needed to understand the biological phenomenon of growth and it is useful in developing a genetic improvement program of Bali cattle production system. Previous studies identified growth pattern of Angus cattle (Beltrans et al., 1992), mature size of Angus cow (Archer et al., 1998), mature weight or puberty weight of Bali cattle , and mature weight of Holstein cow (Berry et al., 2005). However, there is no information of growth curve and mature size of body measurements of Bali cattle.
This study is aimed to analysis of the growth curve of body measurements namely withers height (WH), hip height (HH), body length (BL), chest girth (CG), chest depth (CD), chest width (CW), rump length (RL), hip width (HW), thurl width (TW), and pin bone width (PBW) during growing period of bulls and heifers of Bali cattle, and to estimate of mature size along the growing period of Bali cattle. Additional objectives were to clarify the effects of place, sex and age on the growth of body measurements of Bali cattle.

Data Source, Animal Management and Parameters
The Bali cattle were reared at local farmer by traditional rearing system at Bone and Barru District, South Sulawesi, Indonesia. The location of Bone district was at the hill and the Barru district was near the beach. The cattle at both of places were continuously grazed on paddy field or backyard and they were fed by ad libitum field grass without any additional supplement or concentrate. Sometimes the napier grass and the salt block were given to the cattle.
The bulls and heifers at Bone district were born from 22 sires and those at Barru district were born form 12 sires. The cross-sectional data for ten body measurements (WH, HH, BL, CG, CD, CW, RL, HW, TW, and PBW, respectively) were recorded on 108 bulls and 146 heifers at Bone district and those of 152 bulls and 110 heifers at Barru district at the age of 12, 15, 18, 21, and 24 months. All body measurements were recorded in centimeters unit using the calibrated calipers and the steel rods.

Growth Functions
Least square means were calculated as appropriate. An analysis of variance was carried out to determine the differences of the growth of body measurements of Bali cattle among the place, sex, and age effects and it were also conducted for the main effect of place, sex, and age group as the independent variables whereas the degrees of maturity for body measurements as dependent variables. Data were analyzed by the least squares and maximum likelihood procedure (Harvey, 1977) in which the model was: Y ijkl = µ + P i + S j + A k + e ijkl where Y ijkl = observed linear measurement of body measurement; µ = overall mean; P i = effect of i th place (i = 1,2); S j = effect of j th sex (j = 1,2); A k = effect of k th age (k = 1, 2, 3, 4, 5); e ijkl = residual error of the dependent variable In this study, growth pattern were obtained from Brody growth curve models (Koenen and Groen, 1996) to estimate the growth curve parameters under individual records for the body measurements of Bali cattle datasets. The formula used to estimate the parameters of the growth curve model was as follows: where Y = observed body measurements of bulls or heifers of Bali cattle at age t; A = estimate of mature size; λ = constant; β = rate of maturity; t = value at t months of age.

RESULTS AND DISCUSSION
The development and growth pattern after weaning was generally influenced by genetic growth potential of each cattle, sex, hormone, environment, rearing place, and rearing management system but nutrition level of feeding is a major factor. The growth of body measurements are post-natal growth and it is mostly expressed as a continuous distribution and thought of an associated strategy for the genetic improvement The analysis of variance of growth rate of body measurements of Bali bulls and heifers are presented at Table 1. Significant place, sex, and age effects were present for the growth of all body measurements of Bali bulls and heifers. Generally the mean of growth body measurements of heifers of Bali cattle were higher than those of bulls except the growth of WH, HH and BL at adult age (over 18 months of age). It could be related to the preparation condition for the growth of reproduction organs. In cattle, muscle distribution is influenced more by sex than by breed. In the fact, the growth of proximal hindlimb and abdominal muscles were heavier in heifers than in bulls.
Bali cattle is Bos sondaicus that have relatively small body size and have slow growth rate and mature size compare with the other Asia beef breed of Bos indicus (Jelantik et al., 2008) and British breeds of Angus, Simmental, and Shorthorn (Cundiff et al., 1993). The cattle breeds of small mature size have low of the average daily gain and narrow of pelvis development which indicates of low muscling in addition and slow skeletal development (Alberti et al., 2008).
Place and age effects gave highly significant effect (P<0.01) to all of the growth of body measurements of Bali cattle except those of CW and PBW (P<0.05). These results indicated that rearing place was one of important factor to let the cattle growth optimally. Beside that the results of age effect could be used as a basic achievement of adequate growth and reproductive performance. On the other hand the growth of WH, HH, CD and TW of Bali cattle were not significantly affected by sex effect.
The body measurement allows us to draw conclusions concerning maturity and may also serve as important selective considerations (Szabolcs et al., 2007). The importance of body size to efficiency become to be traits associated with size, mass and body measurement being included in selection programs and breeding objectives. In Japan, fattening cattle in the field were usually measured of withers height, chest girth and body length. The height of a beef animal at a given age could be used to predict of its growth curve and fattening pattern as well as its mature size.
The least square means and standard errors for body measurements by age group for Bali cattle using the parameters derived from the Brody models are shown at Table 2.
All of the body measurements were increasing rapidly from 12 months to 24 months of ages and it still tended to grow based on the growth curve. Generally the growths of all body measurements were fast between the ages of 12 and 15 months. Even though the body measurements namely RL, HW, TW, and PBW showed slowly of growing rate. This result showed that the fattening program of Bali cattle could be continued after 24 months of age. Thus further investigation of the real mature age and mature size of Bali cattle are needed.
The real mature age of Bali cattle was unknown exactly. Generally, the mature age of Bali bulls were started if the red hair and reddish brown color on the body begins to darken, to be  (Martojo, 2012). There are some difficulties to explain the changes of body size which be observed throughout the life cattle because the shapes of cattle are determined by differences in relative growth. An appropriate way to describe them using few parameters is to use mathematical models. Growth models mathematically express the lifetime growth course. The simplest equation to explain the growth function is the Brody model that was used to estimate the growth curve parameters (e.g. mature body measurements, maturing rate, degree of maturity, etc.). Hirooka (2010) showed that mathematical models for growth have been used for many years in animal science to describe the change in body weight with age. Previous studies were examined the fitting non-linear growth model for describing growth pattern of body measurements and estimate curve parameters in Japanese calves (Kumazaki et al., 1955) and in Japanese Black females (Obata and Mukai, 1982;Wada et al., 1983). However there is no report about nonlinear model fitted to the growth curve of body measurements of Bali cattle. The estimates of growth curves of body measurements of Bali cattle at Bone and Barru District based on the Brody models are plotted at Figure 1 and Figure 2. The results showed that the bulls at Barru district were start to reach the mature size at 24 months of ages of WH (106.2 cm), HH (106.5 cm), BL (102.1 cm), CG (136.3 cm), CD (53.3 cm), CW (27.0 cm), TW (31.5 cm), and PBW (15.8 cm), respectively. At similar ages, the bulls at Bone district were start to reach the mature size only for CD (54.4 cm) and RL (33.9 cm). In the case of heifer, only the PBW (16.7 cm) of heifers at Barru district were start to reach the mature size while those at Bone district were start to reach the mature size of HH (108.1 cm) and CD (53.9 cm) at the age of 24 months. Those indicated that the growth curves of all body measurements of bulls and heifer at both places were still increased and it was not reached the real mature size yet. Panjaitan et al. (2003) reported the mature height (114.7 cm) of female Bali cattle were reached at the age of 2.5 -3.0 years and those of 117.6 cm by Pastika (1976). The different situation was come when the mature size is based on the growth of carcass traits. Sri Rachma and Harada (2010) reported the estimate carcass traits of Bali cattle using ultrasound that the Bali bulls were also start to reach the mature period at the 24 months of ages but it still tend to grow. Those results showed that the mature size and growing rate of Bali cattle still very variables.
Based on data of normal growth curve of Japanese Black cattle (The Japanese National  Minezawa (2003) found that the Japanese Black, Poll, and Shorthorn cattle were shown the means of mature withers height of 124 cm, 122 cm, and 128 cm, respectively. Average mature weights of Bali bull for NTB, NTT, and South Sulawesi range 335-363 kg  and mature weight of Bali female for NTB, NTT, and South Sulawesi are 241.9 kg, 221.5 kg, and 211.0 kg, respectively (Martojo, 2012). However, there is no report were presented to compare the mature size and age based on body measurements of Bali cattle. Those results could be use as basic information for fattening program, optimum time to slaughter the cattle, and optimum time to select the candidate sire of Bali cattle at both places. The estimates of mature size, rate of maturity, and coefficient of determinations (R 2 ) of body measurements of bulls and heifers of Bali cattle at Bone and Barru district fitted by Brody Chest Girth (cm))) model are presented at Table 3. All of the values of estimate mature size were higher than the real value of body measurements at 24 months of age that presented in Figures 1 and 2 Rump Length (cm) 000 measurements of Bali bulls and heifers do not reached at the age of 24 months yet. Late mature at cows tended to have higher weight at maturity (Kratochvilova et al., 2004). That results refer that there is a possibility to have higher weight at maturity because Bali cattle tended to have late matured. Generally, the mature size of the bulls at Bone district was higher than those at Barru district. This was because of the different rearing system of Bali cattle in those two regions. The Bali cattle at Bone district were reared by semi intensive system which was kept at the simple paddock with the feeding of cut and carry system. On the other hand, the rearing system of Bali cattle at Barru district were extensive system which the cattle were grazed to the hills, paddy field, corn field or peanut field that far away from residential areas and relatively without any owner supervision. The feeding types that were consumed of Bali cattle at both districts were rather similar. They were fed the grass field, waste of corn plantations, waste of peanut plantations and sometimes the salt block was given. It was shown that the Bali cattle performance is varied and dependent upon environment effect such as feed and temperature beside the genetic effect of the sire or dam.   Table 1 increasing at 24 months of age and not reaching the mature size yet. The place, sex and age factors were significantly affected to the growth of body measurements of Bali cattle.

ACKNOWLEDGMENT
This study was supported by the Directorate of Higher Education of Indonesia for providing the fund of Hibah Bersaing XIII-2005 and the Directorate of Human Resources-Directorate General of Higher Education-Ministry of National Education Indonesia for providing the fund under the Program of Academic Recharging (PAR-C) 2010. The authors wish to thank to Animal Husbandry Service of Barru and Bone District South Sulawesi-Indonesia with all the staffs and the farmers for technical assistance in the collecting field data.