Growth performance of Red Chittagong and Holstein crossbred bull calves using growth promoter

The aim of the study was to evaluate and compare the effect of growth promoter ‘Megavit-DB’ on growth performance of indigenous Red Chittagong (RC) and Holstein Crossbred (HC) bull calves. For this purpose, six RC and six HC bull calves were assigned into four treatment groups having three calves in each as RCT0 (RC without Megavit-DB), RCT1 (RC with Megavit-DB), HCT0 (HC without Megavit-DB) and HCT1 (HC with Megavit-DB). The daily DM intake of different treatment groups were found almost similar. The daily average live weight gains were 0.27±0.05, 0.36±0.01, 0.36±0.01 and 0.45±0.05 kg/d, feed conversion efficiency were 9.08±0.16, 7.47±1.07, 7.13±1.24 and 6.16±0.27 and the average net returns (Tk.) were 1473.33±87, 2060±76.38, 1910±86.60 and 2776.67±44.10 for RCT0, RCT1, HCT0 and HCT1 treatment groups, respectively. The daily average live weight gain and feed conversion efficiency were significantly (p<0.05) higher in HCT1 than that from RCT1, HCT0 and RCT0. Accordingly, the average net returns were found significantly (p<0.05) higher in HCT1 than RCT1, HCT0 and RCT0. It may be concluded that Megavit-DB may have the potentials to improve growth performance of both HC and RC and may be used in cattle fattening program.


Introduction
There is a great scarcity of animal protein for human consumption in Bangladesh.There is no beef breed and therefore, to meet up the deficiency, small scale bull calves fattening program is essential.In this context there is evidence of profitable beef production with male calves obtained from dairy farm which was reported by Buaphun et al., (2000).Furthermore, there are reasons to believe that the cost of dairy beef production can be further decreased through formulation of cheaper rations as well as improving calf management practices.Dairy beef production with appropriate economy of scale, through integrated farming approach utilizing crop by-products and wastes, with secured link to good quality beef market or cooperatives, can become a very viable enterprise in Southeast Asian countries in the coming decades.New products and technologies are continually introduced to beef producer.In general, most products or technologies require an increase in input with the expectation of an improvement in animal performance that will return an increase in cash flow above the cost of implementing the new technology.Growth promoters are those non-nutritive substances, which enhance the body weight gain of animal.Growth implants were first approved for beef cattle in the 1950 (Raun and Preston 1997).The use of growthpromoting implants in suckling beef calves increases average daily gain by 0.04 kg/day in steers and by 0.05 to 0.06 kg/day in heifers (Selk, 1997).However, it is important to use only products labeled for use in beef calves.The rice straw is the basal feed for ruminants, which is well known for its low digestibility and nutritive value.Thus, there is an urgent need for feed supplementation along with basal diet to get more benefit from beef cattle.Megavit-DB is a feed supplement marketed by Novartis Bangladesh Limited which contains vitamin, amino acid, calcium and other minerals.After deworming and antibiotic treatment, uses of Megavit-DB help in rapid growth of animals.Megavit-DB increases disease resistance and enhance fattening of bull calves.Considering the above facts, the present study was undertaken to compare the growth performance of Red Chittagong and Holstein Crossbred bull calves and calculate the cost-benefit of cattle fattening using growth promoter "Megavit-DB".

Materials and Methods
The experiment was carried out at the Dairy Farm, Bangladesh Agricultural University, Mymensingh for a period of 98 days.Twelve weaned, sound, healthy bull calves (six Red Chittagong and six Holstein Crossbred) of approximately similar age (1.5-1.6 yrs) and weight (106-117 kg) were selected from BAU Dairy Farm.All the bull calves were kept individually in the stall and fed individually.The house was well ventilated and the space per animal was adequate.Cleaning and hygienic management of the individual pen was maintained regularly.Vaccination (BQ-vaccine, Anthrax spore vaccine, FMD-vaccine, and HSvaccine) and deworming (Endex-1500 bolus) were done.After deworming the experimental animals were allowed for 15 days to adjust themselves with the experimental condition and diet.The animals were divided into four groups as RCT 0 (Red Chittagong without Megavit-DB), RCT 1 (Red Chittagong with Megavit-DB), HCT 0 (Holstein Crossbred without Megavit-DB), HCT 1 (Holstein Crossbred with Megavit-DB).Green grass was supplied adlibitum and 0.75 kg concentrate mixture was provided for all calves.Only the group RCT 1 and HCT 1 were supplied Megavit-DB (Novartis Bangladesh Limited) at a rate of 17 g/animal/d as an addition to the daily ration.The concentrate mixture was composed of Wheat bran (300 g/kg), Rice polish (300 g/kg), Sesame oil cake (100 g/kg) and Fish meal (50 g/kg).Common salt was supplied on the basis of 1kg/100kg concentrate mixture.The ration was formulated according to Agricultural Research Council (ARC 1990).The daily amount of roughages and concentrate for each animal were divided into two parts and supplied at 8.00 am and at 4.00 pm.Fresh drinking water was made available.The animals consumed all of the concentrate (0.75 kg/animal/d) but there were some leftover of green grass every day.The green grass intake was calculated by subtracting the amount of leftover from the amount of green grass supplied previous day.The initial body weight of each animal was recorded and the animals were weighed weekly by using weigh band and the weighing were carried out at the same time before morning feeding.The live weight gain was measured by subtracting the initial live weight from the final live weight.The rate of gain per day was calculated by dividing the total live weight gain by the number of total experimental days.Cost and returns of the experimental bull calves were calculated considering Initial cost, Feed cost (Green grass @ Tk.2/kg, Wheat bran @ Tk.16/kg, Sesame oil cake @ Tk.20/kg, Fish meal @ Tk.44/kg, Salt @ Tk.15/kg), Growth promoter cost (Megavit-DB) @ Tk.290/kg, Deworming cost @ Tk.15/tablet and Miscellaneous cost @ Tk.50/group.Return was calculated considering return from cow dung selling @ Tk.0.50/kg and return from bull selling based on BAU Dairy Farm auction price in the month of August-September, 2009.The data were analyzed statistically designed in Randomized Complete Block Design (RCBD) using the MSTAT statistical package program.One-way analysis of the variance was done by using statistical difference among the treatments.Duncan's Multiple Range test was also done to compare the treatment means (Gomez and Gomez, 1984).

Feed intake
The average daily total (green grass and concentrate) dry matter (DM) intake of different treatment groups of the experimental animals are shown in Table 1.It was observed that there were no significant (p>0.05)difference in daily DM intake among the treatment groups.These results are in agreement with the findings of Reed and Whisnant (2001) who found that monensin supplementation had no effect on feed intake.The effect of recombinant somatotropin, Synovex and their combination on DM intake was not significant (p>0.05) in intact male calves reported by Holzer et al. (1999).TengYun et al. (2001) reported that cysteamine had no stimulatory effect on feed intake.In contrast, WonMo et al (1998) reported that implanted growth promoters (zeranol 36 mg or progesterone 200 mg + estradiol benzoate 20 mg) at 8, 11 and 14 months of age in Hanwoo steers had significant effect on daily feed intake (kg/head).In another experiment, Rumsey et al (1999) found that DM intake for Synovex-implanted steers was higher (p<0.01)than control (9.2 vs 8.5 kg/day).The effects of feed intake of these findings are different from the present findings probably due to different type of growth promoters used, breed differences, environment and managemental differences.

Live weight gain
The mean for live weight gain and cumulative live weight gain in animals of different treatment groups are presented in Table 1.It is evident from the result that both total live weight gain and daily average live weight gains of RCT 1 was significantly (p<0.05)higher than that of RCT 0 .Likewise, the bull calves of HCT 1 showed significantly (p<0.05)higher result than those of HCT 0 .It is evident from the result that the animals belonged to group HCT 1 showed significantly (p<0.05)higher daily average live weight gains than that of RCT 1.The daily average live weight gain of the present study agrees with the findings of Salles et al., (2000) who reported that addition of monensin (a growth promoter) significantly (p<0.05)improved weight gain in Holstein bull calves.Rumsey et al. (1999) also found higher (p<0.01)live weight gain (38.7 kg) with growth promoter Synovex-S implanted steers than that of control.The daily average live weight gain of bull calves in the present experiment are in agreement with those of Lopez and Vazquez (1983) who found daily gains of 530 g in crossbred zebu steers implanted with 24 mg oestradiol-17beta.Similarly, Emery (1988) found that monensin sodium treated cattle grew from -0.03 kg to +0.7 kg per day faster than that of control.

Feed conversion efficiency
The feed conversion efficiency (DMI/LWG) of animals of different treatment groups are shown in Table 1.It was found that the animals belonged to HCT 1 showed significantly (p<0.05)higher feed conversion efficiency (Table 1) than that of HCT 0 .However, significant (p<0.05)difference was also found between RCT 0 and RCT 1 and also between RCT 1 and HCT 1 (Table 1).The findings of the present study are comparable with the findings of Holzer et al. (1999) who found that the average feed conversion efficiency was significantly (p<0.01)increased by recombinant somatotropin treatment by 10% (p<0.05) in Holstein-Friesian bull calves.Similarly, Rausch et al. (2002) found that treatment with bovine somatotropin in growing beef cattle significantly (p<0.05)increased feed conversion efficiency.In another study, Siuta (1991) found that Cytozyme improved feed conversion efficiency of about 6% in Hereford steers.

Economic analysis
The cost and returns of different treatment groups of bull calves are shown in Table 2.There was no differences among the treatment groups for cost but net return from HCT 1 was found to be significantly (p<0.05)higher than those of RCT 0 , RCT 1 and HCT 0 .Similar response was also reported by Hossain et al. (1996) who found that the average net income of each family was higher (Tk.7745.00/season)than untreated group.

Conclusion
It could be concluded from the present experiment that addition of Megavit-DB (l7g/animal/day) could increase the growth performance of both Holstein Crossbred and Red Chittagong bull calves.

Table 2 . Cost and return of fattening of the experimental bull calves under different groups
RCT 1 = Red Chittagong bull calves with Megavit-DB, HCT 0 = Holstein Crossbred bull calves without Megavit-DB, HCT 1 = Holstein Crossbred bull calves with Megavit-DB, Values are Mean±SE, abc =Mean values having different superscripts in the same row differ significantly (p<0.05),NS=Non Significant, * indicates significant (p<0.05),LSD=Least Significant Difference, SE=Standard Error #RCT 0 = Red Chittagong bull calves without Megavit-DB,