• Asian-Australasian Journal of Animal Sciences
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• v.23 no.3
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• pp.355-365
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• 2010

The aim of this study was to investigate the effect of supplemental recombinant bovine somatotropin (rbST) and cooling with misters and fans on renal function in relation to regulation of body fluids in different stages of lactation in crossbred Holstein cattle. Ten, 87.5% crossbred Holstein cattle were divided into two groups of 5 animals each, housing in a normal shaded barn (NS) and in a shaded barn with a mister-fans cooling system (MF). The experiment in each group was divided into 3 phases, early- (Day 75 postpartum), mid- (Day 135 postpartum), and late stage of lactation (Day 195 postpartum). The pre-treatment study was conducted on the starting day of each stage of lactation and the treatment study was performed after the end of the pre-treatment, during which the animal was injected with 500 mg of rbST (POSILAC) every 14 days for three times. During the study, ambient temperature at the hottest period daily in the MF barn was significantly lower, while relative humidity was higher than that of the NS barn. The temperature humidity index (THI) in both barns ranged from 79-85 throughout the periods of study. Cows in the MF barn showed a lower rectal temperature and respiration rate as compared with cows in the NS barn. The effect of rbST administration increased both rectal temperature and respiration rates of cows housed in either the NS or MF barn. Milk yield significantly increased in cows treated with rbST in all stages of lactation. Increases in mammary blood flow, accompanied by increases of total body water (TBW), extracellular fluid (ECF), blood volume (BV) and plasma volume (PV), were observed in both groups of cows receiving rbST in all stages of lactation. No alterations of renal blood flow and glomerular filtration rate were observed in cows receiving rbST, but decreases in urinary excretion and fractional excretion of sodium, potassium and chloride ions appeared to correlate with reduction in the rate of urine flow and osmolar clearance during rbST administration. These results suggest that the effect of rbST supplementation to cows housed either in NS or MF barns on body fluid volume expansion is attributable to changes in the rate of electrolyte excretion by the kidney. The increased availability of renal tubular reabsorption of sodium, potassium and chloride ions during rbST treatment was a major factor in retaining body water through its colligative properties in exerting formation of an osmotic force mechanism.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1407-1416
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• 2007

Ten, first lactation, 87.5%HF dairy cattle were used to investigate effects of long-term administration of recombinant bovine somatotropin (rbST) on nutrient uptake by the mammary gland at different stages of lactation. Measurements of arterial plasma concentrations and arterial-venous differences of metabolites across the mammary gland were performed in combination with measurment of mammary blood flow to estimate the mammary uptake. Animals in experimental groups were injected subcutaneously every 14 days from day 60 of lactation with a prolonged-release formulation of 500 mg of rbST (POSILAC, Monsanto, USA) or with sterile sesame oil without rbST in the control group. During early lactation, the milk yield of rbST-treated animals was higher than that of the control animals (p<0.05). The peak milk yield in both groups of animals declined from the early period of lactation with progression to mid- and late-lactation. No significant changes were observed in the concentration of milk lactose, while the concentrations of milk protein significantly increased as lactation advanced to mid- and late-lactation in both groups. Milk fat concentrations were significantly higher in rbST-treated animals than in control animals, particularly in early lactation (p<0.05). Mammary blood flow (MBF) markedly increased during rbST administration and was maintained at a high level throughout lactation. The mean arterial plasma concentrations for glucose and acetate of rbST-treated animals were unchanged. The net mammary glucose uptake of rbST-treated animals increased approximately 20% during early lactation, while it significantly decreased (p<0.05), including the arteriovenous differences (A-V differences) and extraction ratio across the mammary gland, as lactation advanced to mid- and late-lactation. A-V differences, mammary extraction and mammary uptake for acetate increased during rbST administration and were significantly higher (p<0.05) than in the control animals in early and mid-lactation. Mean arterial plasma concentrations for ${\beta}$-hydroxybutyrate and free glycerol were unchanged throughout the experimental periods in both groups. A-V differences and extraction ratio of ${\beta}$-hydroxybutyrate across the mammary gland did not alter during rbST administration. Mean arterial plasma concentrations for free fatty acids ($C_{16}$ to $C_{18}$), but not for triacylglycerol, increased in rbST-treated animals and were significantly higher than in control animals during early lactation (p<0.01). These findings suggest that an increase in MBF during rbST administration would not be a major determinant in the mediation of nutrient delivery and uptake by the mammary gland for increased milk production. Local changes in biosynthetic capacity within the mammary gland would be a factor in the utilization of substrates resulting in the rate of decline in milk yield with advancing lactation.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.332-338
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• 1999

This study was carried out to investigate weight gain and prevention of diarrhea in suckling calves which were injected with recombinant bovine somatopropin (rBST). A total of 101 breeding cows were assigned to the six groups according to the administered dosage and injected time, respectively. Groups T-1, T-3, T-4 and T-6 were injected starting 1 week before calving and groups T-2 and T-5 were injected on the calving day. The six groups were injected five times at two week intervals. Groups T-1 and T-2 were injected with 250mg composite rBST, Group T-3 was injected with 375 mg composite rBST. Groups T-4 and T-5 were injected with 500mg composite rBST, And group T-6 was injected with 500mg rBST-S. The control group was not injected with BST. The groups injected with 500 mg BrST had a lower rate of morbidity from diarrhea than the control group or the groups injected with 250 mg rBST (T-1 and T-2). Weight gain was higher in group T-4 than in the control group or groups T-1 and T-2. In Korean Native Cattle, the total weight gain was greater in group T-4 than in the control group (p<0.05). In crossbred cows, total weight gain was the highest in group T-4, and the total weight gain rate was greater than in group T-4 and the control group (p<0.05). The results of the hematological values showed that injections of rBST did not affect the level of the RBC, TP and BUN in the breeding cows at 9 weeks after postpartum or the neonatal calves. The results of this study indicate that injecting breeding cows with 500 mg rBST before calving would be effective in the preventing of diarrhea and in increasing weight gain of calves from birth to weaning.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.123-135
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• 2001

Application of growth promoters by means of implantation or supplementation to the diets has been routine in the beef cattle industry of many countries for the better performance in growth and improvement of feed efficiency. Anabolic implants (zeranol, trenbolone acetate, and estradiol with testosterone or progesterone) have generated various positive effects. Zeranol implantation, in general, improved average daily gain (ADG), feed conversion (FC), dressing percentage (DP) and yield grade (YG) of cattle, and increased dry matter intake (DMI). Trenbolone acetate with or without estradiol also increased mean values of ADG and loin eye area (LEA) but reduced DMI and improved FC of cattle. Estradiol with testosterone or progesterone increased ADG and DMI. Anabolic implants, however, had minimal or negative effects on marbling or quality grade. The magnitude of the response to these anabolic implants in performance of beef cattle has varied depending on the type of implants, amount and duration of exposure, age of animals and combination of implants. Administration of bovine somatotropin improved ADG and FC, and decreased fat deposition. Ionophores improved FC in cattle from reduced DMI without great response to ADG. Supplementation of monensin and lasalocid reduced molar proportion of propionate. Monensin and lysocellin increased apparent absorption and retention of some minerals in cattle. Despite the improved cattle performance in growth and FC, results in beef quality from the application of the growth promoters appeared to vary or in conflict under a variety of environmental conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.404-413
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• 2008

Major objectives were to evaluate effects of three schemes of bST-supplementation of Holstein cows (142.8 mg/14 d, POSILAC) during the prepartum and/or postpartum periods through 63 d (${\pm}3d$) of lactation. Measures evaluated the potential of treatments to improve body weight (BW) and body condition score (BCS), provoke changes in plasma concentrations of somatotropin (ST) and IGF-I, and improve milk yield, milk composition (percentages of protein and fat, and somatic cell counts), and several calving variables. Multiparous Holstein cows were randomly assigned to a $2{\times}2$ factorial arrangement of treatments (TRT) to give four groups (I = no bST, n = 26; II = bST postpartum, n = 25; III = bST prepartum, n = 27; IV = bST prepartum and postpartum, n = 25). During the prepartum period, cows in groups I and II were not supplemented but those in groups III and IV were supplemented every 2-wk beginning 21 d before expected calving date through calving. During the first 63 DIM only cows in groups II and IV were supplemented with bST. From 64 DIM through the end of lactation cows in all groups were supplemented with the full lactation dose of bST (500 mg/14 d). The BW and BCS were recorded weekly throughout the prepartum and postpartum periods and every 2-wk beyond 70 DIM. Blood samples were collected 3-times a week for analyses of ST and IGF-I. Milk yields were recorded daily though 150 DIM. Prepartum supplementation of bST did not affect BW or BCS, but mean concentrations of ST were increased 12.2% and were 15.5% greater at calving. Overall, mean concentration of IGF-I was not affected by treatment but concentrations were greater at 1 and 2 wk before calving in bST-supplemented cows. During the first 63 DIM the BW and BCS were not affected by treatment. Significant effects of bST-supplementation were detected on concentrations of ST, IGF-I and on milk yield compared to non-supplemented cows in group I. Postpartum concentrations of ST were greater in bST-supplemented cows (TRT II and IV; +41.9 and 54.6%). However, concentrations of IGF-I were greater only in cows in group IV (+25.9%) during the postpartum period. Overall, the three bST-supplemented groups had greater actual milk yield than the control group (I) during the first 63 and 150 DIM. The actual milk yields during 63 and 150 DIM were 6.5 and 4.6 kg/d greater for cows in group IV than cows in group I and the 305-d ME milk yield also was 15.6% greater. No adverse effects of TRT were observed on calf birth weight, colostrum immunoglobulins, ease of calving or other measures evaluated.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.269-274
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• 2003

The purpose of this study was to determine the effect of rbST treatment on progesterone concentration, volume of luteal tissue and pregnancy rate following embryo transfer. Recipient cows were assigned to control and rbST group, of which was given a single injection of rbST (500 mg. sc) at estrus detection. The concentration of progesterone was not significantly different between control and at 0, 3, 6 days after rbST treatment. However, the concentration of progesterone at 9, 12 days was significantly higher than in control group (4.6 and 6.8 vs. 3.9 and 4.5 ng/ml P4). The pregnancy rate after embryo transfer in rbST treatment was significantly higher than in control group (64.0 vs. 47.1 %; p<0.05). The results indicated that rbST treatment in recipient cows could be improved the efficiency of pregnancy rate after embryo transfer.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.784-793
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• 2004

Major objective was to evaluate three doses of bST (POSILAC(R)) injected into Holstein cows during the transition period and through 56 d of lactation for potential to improve DMI, BCS, BW, metabolites, hormones, IGF-I and milk production. Biweekly injections of bST (0, 5.1, 10.2, or 15.3 mg bST/d) began 28 d before expected parturition and continued through 56 d postpartum. Twenty-three of the 25 multiparous Holstein cows assigned randomly to four groups completed experiment (7, 5, 6 and 5 cows/group, respectively). The DMI, BW and BCS were recorded weekly throughout the prepartum and postpartum periods and blood samples were collected thrice weekly for analyses of ST, insulin, $T_{4}$, $T_{3}$, IGF-I, glucose and NEFA. Milk yields were recorded daily through 60 d postpartum and milk components measured once weekly. Mathematical model for data analyses for prepartum and postpartum periods included treatment, calving month, and the two-factor interaction. Cows injected with 10.2 and 15.3 mg bST prepartum had greater mean prepartum concentrations of ST and IGF-I. Prepartum injections of bST did not affect prepartum BW or BCS. On average, cows injected postpartum better maintained their BCS during first 60 d of lactation (3.15$\pm$0.06, 3.12$\pm$0.007, 3.20$\pm$0.006 and 3.58$\pm$0.009). Treatments did not affect mean prepartum DMI but cows injected with 15.3 mg bST/d had greatest DMI and greatest mean daily MY during the first 3 wk and tended to be greater during first 60 d of lactation. Cows injected with two highest bST doses (10.1 and 15.2 mg/d) had greater mean postpartum concentrations of ST and $T_{3}$, but IGF-I, $T_{4}$, glucose and NEFA did not differ across groups. No adverse effects of bST treatment were observed.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.570-575
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• 2002

Effects of active immunization against native 14-mer somatostatin (SRIF, somatotropin releasing inhibiting factor) and its two 14-mer-somatostatin analogues on the milk production in rat mammary cells were studied. Native SRIF, Tyr11-somatostatin (Tyr11-SRIF), and D-Trp8, D-Cys14-somatostatin (Trp8Cys14-SRIF) were conjugated to bovine serum albumin (BSA) for immunogen preparation. Twenty-four female Sprague-Dawley rats were divided into four groups and immunized against saline (Control), SRIF, Tyr11-SRIF, and Trp8Cys14-SRIF at five weeks of age. Booster immunizations were performed at 7, 9, and 11 weeks of age. SRIFimmunized rats were mated at 10 weeks of age. The blood and mammary glands were collected at day 15 post-pregnancy and -lactation. To measure the amount of milk protein synthesis in the mammary gland, mammary cells isolated from the pregnant and the lactating rats, were cultured in the presence of $^3H$-lysine. No significant differences in growth performance, concentration of growth hormone in the circulation, and the amount of milk protein synthesis were observed among the groups. Inductive levels of serum anti-SRIF antibody in the SRIF and Tyr11-SRIF groups but not in the Trp8Cys14-SRIF group, were significantly higher than that of the control group during the pregnancy and lactation periods. The result suggests that active immunization against native 14-mer SRIF and Tyr11-SRIF was able to induce anti-SRIF antibodies, but did not affect the milk protein synthesis.

• Journal of Embryo Transfer
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• v.11 no.2
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• pp.103-109
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• 1996

The aim of this study was to evaluate the effect of recombinant bovine somatotropin (bST; Boostin-S, LG Chem) treatment with FSH (Super OV) or PMSG on superovulatory response for transvaginal ultrasound-guided oocyte retrieval (TVR) in calves. Eight Korean Native Cattle(KNC) heifer calves; 150 to 240 days old; were randomly assigned to four treatment groups: 1) FSH(75 mg); 2) FSH (75 mg) + bST(500mg) 3) PMSG(1;000 IU); 4) PMSG(1, 000 IU) + bST(500 mg). Experimental calves in group 1 (n=2) and 2(n=2) were weekly superovulated for 4 consecutive weeks with daily injection of FSH for 3days and the next day subjected to TVR session. Animals in group 3 (n=2) and 4(n=2) were weekly stimulated for 4 consecutive weeks with a single dose of 1, 000 IU PMSG. TVR was performed on 72 hours after PMSG injection. Calves in group 2 and 4 was received injection of 500 mg of bST every 10 days. At each TVR session, follicle number and size were recorded; the oocytes collected and graded according to cumulus and cytoplasm investment. Collected oocyte were determined viable oocyte according to morphological quality with granulation of oocyte and number and status of cumlulus cells. IVM and IVF were performed and assessed cleavage rate on day 3 after fertilization. A Sonovet 600(Medison, Co., Ltd) realtime ultrasound scanner with a 6.5 MHz convex transducer, fixed at the tip of 500 mm estended handle equipped with a needle guide was used in collecting oocyte. Differences between groups were analysed by chi-square test. The population of large follicle ($\geq$5 nun) and aspiration rate were not significant different among the 4 groups. But, the number of small follicles (<5 mm) and aspirated oocyte in the KNC calves treated with bST were 1.3~1.6 times higher than in KNC calves treat with FSH or PMSG alone. In conclusion, the administration of bST with FSH or PMSG at superovulation for TVR in calves was increase the nurnber of small follicle which was influenced the number of aspiratable follicle.

• Korean Journal of Animal Reproduction
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• v.24 no.2
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• pp.163-170
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• 2000

This study was conducted to examine the effects of recombinant Bovine Somatotropin (rBST), vitamin E(Vit. E) and selenium (Se) administration on the blood chemical values and hormone concentrations of serum in Hanwoo sires. Hanwoo sires were randomly assigned to five groups; 1) control, 2) rBST,0.09mg/kg body weight (BW), 3) Vit E, 1,500IU/kg BW, 4) Se 0.1mg/kg BW, 5) Vit E, 1,500IU plus Se 0.1mg/kg BW. rBST, Vit. E and Se for each experimental group were given 6 times at 15 days interval by intermuscular injection. Blood samples were collected ten times for experimental periods and separated the serum by centrifugation and stored into deep freezer. The concentration of albumin was the highest in Se group than those of any other groups (P＜0.05) and Vit. E plus Se group was significantly higher than in the control and rBST groups (P＜0.05). The concentrations of blood urea nitrogen (BUN) and creatinine were significantly higher in rBST group than any other groups (P＜0.05). The concentration of total protein in rBST, Se and Vit. E plus Se groups were significantly higher than in control group (P＜0.05). The concentrations of calcium, cholesterol,, glucose, inorganic phosphorus and triglycerides in serum were not difference in all experimental groups (P＞0.05). The concentration of estradiol was slightly higher in Se and Vit. E plus Se groups than those of any other groups, but not significantly difference among the experimental groups (P＜0.05). The concentration of testosterone was not affected by the administration of rBST, Vit. E and Se.