D. Sastradipradja’s research while affiliated with IPB University and other places

Abstract dalam bentuk hard copy

A study was carried out to determine glucose kinetics, nutrient balance and milk production of lactating Etawah crossbred goats. The animals (27.2 to 29.1 kg BW) were randomly divided into four levels of dietary treatment groups: the first group R1 received 100% (3 kg) fresh king grass (Penisetum purpuroides), the second group R2 received 75% king grass and 25% king grass silage prepared with chicken manure, the third group R3 received 50% king grass and 50% silage, and the fourth group R4 received 100% silage. In addition to the roughage, each group received 800 g of concentrate (CP 14.77% of DM; 17.26 MJ/kg). Animals fed king grass silage made with chicken manure were found to be superior to the group fed king grass alone. Glucose kinetics and retained energy were significantly affected. Calculations showed that glucose requirements for maintenance and milk production can be met for the groups with high levels of silage (R3 and R4). The values of glucose flux were in the range of 2.52 to 4.50 mg/min.kg which are lower, but close to, the values for the temperate lactating dairy cow. The present glucose flux value for the lactating Etawah crossbred goat is higher than the previous value published from this laboratory.

A study of mammary function in relation to glucose metabolism of first lactation Bali cows on grass-legume diets was carried out using 12 primiparous cows (initial BW 263.79±21.66 kg) for 16 weeks starting immediately post calving. The animals were randomly allocated into 4 dietary treatment groups R1, R2, R3 and R4, receiving from the last 2 months of pregnancy onwards, rations based on a mixture of locally available grass and legume feed ad libitum. On a DM basis R1 contained 70% elephant grass (PP, Penicetum purpureum) plus 30% Gliricidia sepia leaves (GS), R2 was 30% PP plus 25% GS supplemented with 55% Hibiscus tilliacius leaves (HT, defaunating effect), R3 and R4 were 22.5% PP+41.25% GS+11.25% HT+25% concentrate, with R4 supplemented with zinc-diacetate. TDN, CP and zinc contents of the diets were 58.2%, 12.05% and 18.3 mg/kg respectively for R1, 65.05%, 16.9% and 25.6 mg/kg respectively for R2, 66.03%, 16.71% and 29.02 mg/kg respectively for R3 and 66.03%, 16.71% and 60.47 mg/kg respectively for R4. Milk production and body weights were monitored, an energy and protein balance trial conducted, overall glucose kinetics parameters assessed, mammary blood flow (MBF) and metabolite arteriovenous differences (Δ AVs) measured to get uptake data and mammary performance relationships. Parameters of glucose kinetics at peak lactation or during dry condition were not affected by ration quality. Glucose pool size, space of distribution and flux increased by 61.77, 62.26 and 82.08%, respectively, during lactation compared to the dry period. Mean glucose flux of lactating Bali cows was 5.52 mg/min.kgBW0.807 which resembles the range of values of temperate dairy cows. Calculation showed that glucose requirements for maintenance, milk lactose and fat-glycerol synthesis, and the formation of NADPH reached 461.69 g for a yield of 1 kg/d or equal to 320.62 mg/min, which was less than the average glucose flux of lactating Bali cows of 481.35 mg/min. Mammary blood flow (MBF) values ranged from 56 to 83 l/h for the different treatments and the ratio MBF per kg milk produced imprqved from av. 1540 l/kg for R1 to av. 967 l/kg for R4 treated cows. Mammary glucose uptake ranged from 6.27 to 12.03 g/h or 120 to 140 g/kg milk. Glucose uptake was mass-wise 2 to 4 times the amount secreted as lactose, which indicated values less than the calculated mammary glucose needs and that little lactose was synthesized. The excess glucose taken-up was used for other metabolic processes. Linear relationships between metabolite Δ AVs and arterial blood plasma concentration [A] showed that in Bali cows triglycerides (TG), phenylalanine (Phe) and tyrosine (Tyr) have high coefficients of determination, i.e. 0.77, 0.81 and 0.69, respectively. For glucose, the relationship is quadratic with an R2 value of 0.49. It was concluded that lactose synthesis was inadequate, which led to a speculation that milk yield could be improved by increased lactose synthesis.

A study on energy and protein utilization, and milk production of Bali cows on grass-legume diets was carried out using 12 first lactation cows (initial BW 263.79±21.66 kg) during a period of 16 weeks starting immediately post calving. The animals were randomly allotted into 4 dietary treatment groups R1, R2, R3 and R4, receiving from the last 2 months of pregnancy onwards, graded improved rations based on a mixture of locally available grass and legume feed ad libitum. R1 contained on a DM basis 70% elephant grass (PP, Penisetum purpureum) plus 30% Gliricidia sepia leaves (GS), R2 was 30% PP plus 55% GS supplemented with 15% Hibiscus tilliactus leaves (HT, defaunating effect), R3 and R4 were 22.5% PP+41.25% GS+11.25% HT+25% concentrate, where R3 was not and R4 supplemented with zinc di-acetate. TDN, CP and zinc contents of the diets were 58.2%, 12.05% and 18.3 mg/kg respectively for R1, 65.05%, 16.9% and 25.6 mg/kg respectively for R2, 66.03%, 16.71% and 29.02 mg/kg respectively for R3 and 66.03%, 1671% and 60.47 mg/kg respectively for R4. Milk production and body weight were monitored throughout the experimental period. In vivo body composition by the urea space technique validated by the body density method and supported by carcass data was estimated at the start and termination of the experiment. Nutrient balance and rumen performance characteristics were measured during a balance trial of 7 days during the 3rd and 4th week of the lactation period. Results indicated that quality of ration caused improvement of ruminai total VFA concentration, increments being 52 to 65 % for R2, R3 and R4 above R1, with increments of acetate being less (31 to 48%) and propionate being proportionally more in comparison to total VFA increments. Similarly, ammonia concentrations increased to 5.24 to 7.07 mM, equivalent to 7.34 to 990 mg NH3-N/100 ml rumen fluid. Results also indicated that feed quality did not affect DE and ME intakes, and heat production (HP), but increased GE, UE, energy in milk and total retained energy (RE total) in body tissues and milk. Intake-, digestible- and catabolized-protein, and retained-protein in body tissues and milk (Rprot) were all elevated increasing the quality of ration. Similar results were obtained for milk yield and components with mean values reaching 2.085 kg/d (R4) versus 0.92 kg/d (R1) for milk yield, and 170.22 g/d (R4) vs 71.69 g/d (R1), 105.74 g/d (R4) vs 45.35 g/d (R1), 101.34 g/d (R4) vs 46.36 g/d (R1) for milk-fat, -protein, and -lactose, respectively. Relatively high yields of milk production was maintained longer for R4 as compared to the other treatment groups. There were no significant effects on body mass and components due to lactation. From the relationship REtotal (MJ/d)=12.79-0.373 ME (MJ/d); (r=0.73), it was found that MEm=0.53 MJ/kgW0.75.d. Requirement of energy to support the production of milk, ranging from 0.5 to 3.0 kg/d, follows the equation: Milk Prod. (Qmp, kg/d)=[-2.48+4.31 ME(MJ/kg0.75.d)]; (r-0.6) or Qmp=-3.4+[0.08(ME-REbody tissue)]MJ/d]; (r=0.94). The requirement for protein intake for maintenance (IPm) equals 6.19 g/kg0.75.d derived from the relationship RP=-47.4+0.12 IP; (r=0.74 n=9). Equation for protein requirement for lactation is Qnl=[(Qmp)(% protein in milk)(Imp)]/100, where Qnl is g protein required for lactation, Qmp is daily milk yield, Bali cow's milk-protein content av. 5.04%, and Imp is metabolic increment for milk production (MElakt/MEm=1.46).

A study involving nutrient balances and radioisotope labeling techniques was undertaken to study energy and protein metabolism and glucose kinetics of female crossbred Etawah goats, using 12 weaned (BW 14.0+/-2.0 kg), 12 late pregnant (BW 27.8+/-1.8 kg) and 12 first lactation does (BW 25.0+/-5.0 kg). Each class of animal was randomly allotted into 3 dietary treatment groups R1, R2 and R3, that received 100%, 85%, and 70% of ad libitum feed. The rations offend were pellets containing 21.8% CP and 19.3 MJ GE/kg, except for the lactating does who received pellets (17.2% CP and 18.9 MJ GE/kg) rind fresh Penisetum purpureum grass. Energy and nitrogen balance studies were conducted during a two-week trial. Daily he:at production (HP, estimated by the carbon dioxide entry rate technique), glucose pool and flux were measured. Equations were found for metabolizable energy (ME) and protein intake (IP) requirements for growing goats: ME (MJ/d)=1.87+0.55 RE-0.001 ADG+0.044 RP (R-2=0.89) and IP (g/d)=48.47+2.99 RE+0.029 ADG+0.79 RP (R-2=0.90); for pregnant does: ME (MJ/d)=5.92+0.96 RE-0.002 ADG+0.003 RP (R-2=0.99) and IP (g/d)=58.34+5.41 RE+0.625 ADG-0.30 RP (R-2=0.98); and for lactating does: ME (MJ/d)=4.23+0.713 RE+0.003 ADG+0.006 RP+0.002 MY (R-2=0.86); IP (g/d)=84.05-5.36 RE+0.055 ADG-0.16 RP+0.068 MY (R-2=0.45), where RE is retained energy (MJ/d), ADG is average daily gain in weight (g/d), RP is retained protein (g/d) and MY is milk yield (ml/d). ME and IP requirements for maintenance for growing goats were 0.46 MJ/d.kg BW0.75 and 7.43 g/d.kg BW0.75, respectively. Values for the pregnant and lactating does were in the same order, 0.55 MJ/d.kg BW0.75 and 11.7 g/d.kg BW0.75, and 0.50 MJ/d.kg BW0.75 and 10.8 g/d.kg BW0.75, respectively. Milk protein ranged from 3.06 to 3.5% and milk fat averaged 5.2%. Glucose metabolism in Etawah crossbred female goat is active, but glucose flux is low compared to temperate ruminant breeds which may implicate its role to support production.

Four young swamp buffalo cows of similar age ranging in body weight (W) between 280 to 380 kg and trained for doing physical exercise were used in two consecutive experiments, each using a latin square design, to determine energy expenditure for draught. The experiments consisted of field trials using 4 levels of work load, i.e. no work as control and loads amounting 450 to 500 Newton (N) continuous traction for respectively 1, 2 and 3 h daily for 14 consecutive days for experiment 1, and no work, traction loads equaling 5, 10 and 15% of W for 3 h daily for 14 days for experiment 2. Heart rate during rest and exercise was monitored using PE-3000 HR monitor. Cows were fed only king grass (Penisetum purpuroides) ad libitum and were subjected to balance trials. Body composition was estimated in vivo by the body density method and daily energy expenditure (EE) was calculated from ME minus RE. RE was calculated from the changes in body-protein and -fat measured before and immediately after the 14 d experimental period assuming an energy equivalent of 39.32 MJ/kg fat and 20.07 MJ/kg protein. Eexercise (EEwork - EEresting), which was the energy spent for doing the traction during 1, 2 and 3 h was 7.13, 15.45 and 19.90 MJ, respectively. EEwork for the 1 h treatment group was 39.75 MJ/d equivalent to 1.30 times BEresting. The values for the 2 and 3 h treatment groups were 1.75 and 1.86 times resting energy requirement, respectively. Absolute efficiency of work in all exercise trials of experiment 2 was around 27.28%. The increases of daily Eexercise values were correlated to elevation of heart rate (HR) according to the equation Eexercise=(0.270 HR0.363 - 1) MJ, while draught force related to heart rate according to the equation DF (N)=6.66 HR - 361.62. Blood glucose and triglyceride levels were gradually elevated with time during the course of exercise. Mean values of blood glucose were 91.7, 115.0 and 116.2 mg/dl for cows after 1, 2 and 3 h pulling loads at 15% W respectively as compared to 88.2 mg/dl prior to work. In the same order and treatment, mean blood triglyceride concentrations were 13.5, 13.3 and 14.8 mg/dl, and 11.5 mg/dl for control. For blood lactate, the values were 1.68, 1.63 and 1.66 mM, and 0.80 mM for control. Glucose was used as the major source of energy during the initial phase of exercise, but for prolonged work, fat will replace carbohydrate as the main substrate. Accumulation of lactate persisted for some time at the end of the exercise trials.

Four young swamp buffalo cows of similar age ranging in weight between 280 to 380 kg and trained to do physical work were used in a study to determine energy and protein requirements for draught using a 4×4 Latin square designed experiment. The experiment consisted of field trials employing 4 levels of work load, e.g. no work as control, and loads amounting 450 to 500 Newton (N) pulled continuously for 1, 2 and 3 h daily for 14 consecutive days. Cows were fed king grass (Penisetum purpuroides) ad libitum and were subjected to materials balance trials. Body composition was estimated in vivo by the body density method and daily energy expenditure (EE) was calculated from ME minus retained energy (RE). The results show that EE while not working (EEresting) was 0.42 kgW0.75 MJ/d and maintenance ME (MEm) was 0.37 kgW0.75 MJ/d. ME requirement increased to 1.65 times maintenance for the work of 3 hours. The energy expended for doing exercise (Eexercise) was 9.56, 20.0 and 25.86 MJ/cow for treatments 1, 2 and 3 h, respectively. Fat retention was absent in all groups of working cows, but protein retention was only negative for cows undertaking 3 h work. The relationship between Eexercise (MJ), work load (F, kN), work duration (t, h) and body mass (W, kg) was found to be: Eexercise=(0.003F1.43t0.93)/W0.09 MJ. The maintenance requirement for digestible protein was 2.51 kgW0.75 g/d, whereas digestible protein for growth (DPgrowth) and for work (DPwork) followed the equations: DPgrowth=[(258+1.25W0.75)ΔWkg/d]g and DPwork=[12.59e0.95t]g, respectively The coefficients a, b and c for the calculation of Eexercise components according to the Lawrence equation were found to be 2.56 J/kgW.m, 5.2 J/kg load carried.m and 0.29, respectively, thus efficiencies to convert ME into work were 0, 16.09, 27.3 and 32.44% for control, 1, 2 and 3 h/d work, respectively. ME and DP requirements for a 250 to 400 kg working buffalo cow allowing to growth up to 0.5 kg/d are presented.