Intakes, liveweight gain, hip height gain and body condition score
Feed intake, liveweight gain, body confirmation and body condition score data are presented in Table 2. There was no significant difference in feed intake among treatment groups (P>0.05; Table 2). All bulls ate around 11 kg/d on a DM basis, equal to around 2.8% LW. Our results were above the maintenance level, 2.3% LW (Syahniar et al., 2012). The results demonstrated that the production could be improved in cattle fed concentrate diet and elephant grass, although the supplement did not affect the DM intake across all the treatment groups as they were offered the same cons: EG ratio.
At the start, the liveweight of bulls was not different between treatments (P>0.05). Bulls offered supplement at 0.6 g/kg LW were heavier and gained more LWG (P<0.05; Table 2). The inclusion of 0.3 g/kg LW of supplement in the diet only improved slightly higher LWG, it indicated that the dose of the supplement that should be provided in the diet was 0.6 g/kg LW. Our result was in line with
He et al., (2018) who reported that the supplement increased LWG but did not affect DM intake. Studies showed varied results, the supplement increased the DM intake (
da Cruz et al., 2019) while others showed a decreasing trend in DM intake
(Fiorentini et al., 2014; (
de Souza et al., 2017)). Those varieties of responses depend very much on the basal diet offered to the cattle and the level of which supplement was provided in the diet.
At the end, the BCS was not different between treatments. All groups reached BCS 3, indicating they were all in good condition. The BCS change of those groups was 0.12; 0.08 and 0.13. Our results were in agreement with (
de Souza et al., 2017) who showed that the BCS was not affected by the supplement treatments. The BCS of cattle indicates a good index of subcutaneous fat, such as rump fat thickness although the LW showed a low correlation with both BCS and rump fat thickness
(Ayres et al., 2009; Paul et al., 2020).
The hip height gain was not different between treatments (P=0.19; Table 2). The HH gain was slightly lower than that was reported by
Antari, (2018) in Brahman-cross steers at the same age (85 mm/100 d). Our results showed that the bulls still grew taller but at a slower rate than the previous study, the differences were probably because of the nutritional content of the diet offered to the cattle and the breed.
The supplement included in the diet was related to an increase in FCR, although it was not a significant difference (P>0.05) between each level of supplement. At the highest level of supplement, the bulls required less feed/kg LWG. Our results were within the range reported in the previous studies in Ongole crossbred bulls offered cassava tuber and
Gliricidia sp., the FCR was 18 kg feed DM/kg LWG
(Marsetyo et al., 2021) and in Ongole crossbred bulls fed elephant grass
adlibitum, the FCR was 24 kg feed DM/kg LWG
(Antari et al., 2016).
Plasma glucose and fats
The results showed that glucose, total cholesterol, triglyceride, LDL and HDL did not differ significantly (P>0.05; Table 3). Our results were in contrast to a study in Holstein’s calves fed the same supplement showed significant increasees in triglyceride, cholesterol and LDL concentrations and no supplement effect on glucose concentration was detected
(Ngu et al., 2020). The variety of the results is probably because of the basal diet and the physiological status of the cattle differences.
The fat depth and muscle depth
The depths of backfat and muscle depth were presented in Table 4. There were no differences between treatments in all muscle depth affected by the supplement treatments (P>0.05; Table 4). The muscle depths in our study were larger than those in Bali cattle, around 53.9 mm at the same age at position 12-13
th (
Jakaria et al., 2017), but lower than in Brahman cross steers (
Antari, 2018), the eye muscle areas was around 68 cm
2, the discrepancy of the results probably because of breed differences and feed type offered to the cattle. Thus, the depth of the muscle was likely affected by the basal diet offered to the bulls. The growth rate is affected largely by feed types, intake and chemical composition of the feed. Accordingly, to achieve a fast growth rate, cattle required a high energy and protein intake (
Antari, 2018). Our bulls were relatively young so that the growth and development still occurred. Although the depth of all muscle areas was not different, the bulls fed supplement diet tended to have a larger muscle than their cohorts.
The fat depth in P8 and rump areas was not affected by the supplement treatment but it affected the depth of the fat in positions 12-13
th (P=0.05; Table 4). Our results indicated that the fat diet offered to the bulls affected the fat deposition in the 12-13
th area, the value was larger than those in Ongole crossbred (3.56 mm) and Simmental x Ongole (4.32 mm)
(Ngadiyono et al., 2014). Moreover,
Himia et al., (2021) reported that fat deposition occurred when the muscle growth reached a maximum rate at around the mature weight, after that muscle growth declined and fat deposition started to increase. Meanwhile, the mature weight of cattle occurred at different ages. For example,
Freetly et al., (2011) reported that there was a variety of mature age and weight in beef cattle, the mature age and weight of Brahman cross was 58 weeks and 343 kg, while
Antari (2018) reported that mature age and weight of Brahman cross steers fed high energy and protein diet was 64 weeks and 850 kg. Thus, the fat depth might be vary depending on age, feed and whether the animals were castrated or not.
