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The study aims to investigate the relationships between colostral concentrations of insulin-like growth factor 1 (IGF-1), immunoglobulin G (IgG) and vitamin A (Vit A) and growth (body weight and average daily gain) in Black Bengal (BB) and its crossbred. The colostrum from dams (n = 16) was collected at parturition to measure the concentrations of IGF-1, IgG and Vit A. The kid weight at birth (W-0), day 14 (W-14) and day 28 (W-28) were measured and the average daily gain during day 1-14 (ADG1-14) and day 14-28 (ADG14-28) were calculated. The average concentrations of IGF-1, IgG and Vit A in colostrum were 504.6 ± 74.9 ng/ml, 9.7 ± 0.6 mg/ml and 549.1 ± 72.5 µg/100 g, respectively. The average body weight of kids at birth, day 14 and 28 were 1.72 ± 0.08, 2.95 ± 0.11 and 3.94 ± 0.13 kg respectively. Kid's breed, IGF-1, IgG and Vit A had significant positive effects on ADG14-28 while parity, litter size and sex had no effect. The growth factors that were classified into 2 classes based upon the mean values of colostral contents in all kids showed that the kids receiving the higher concentrations of IGF-1, IgG and Vit A in colostrum had higher body weight gain than those receiving the lower concentrations (92.1 ± 7.8 vs. 59.8 ± 5.7 g/day; p = 0.002, 88.3 ± 7.8 vs. 60.3 ± 6.1 g/day; p = 0.009 and 91.1 ± 6.8 vs. 56.7 ± 5.8 g/day; p 0.001 respectively). It is concluded that IGF-1, IgG and Vit A concentrations in colostrum of dams were associated with increased kid's body weight gain at the end of first month in BB and BB crossbred goats.

Background and Aim: Milk synthesis by the mammary gland is negatively influenced in part by high ambient temperature (AT). This study aimed to clarify the pathway of intramammary glucose utilization involved in mediating lactose synthesis during treatment with somatotropin under housing with misters and fans. Materials and Methods: A single subcutaneous injection of 500 mg of recombinant bovine somatotropin (rbST) was administered 3 times once every 14 days to 87.5% crossbred Holstein cattle in early-/mid-/late lactation, under housing in a normal shaded barn and in a shaded barn with a mist-fan cooling system. Results: The milk yields of the cooled cows tended to increase compared with those of uncooled cows and exhibited more potentiated effects in response to rbST treatment, coinciding with increases in mammary plasma flow and glucose uptake, but not in the mammary extraction of glucose. Treatment with rbST in the cooled cows resulted in a greater increase in the milk glucose concentration and a greater decrease in the milk glucose-6-phosphate concentration at all stages of lactation. Conclusion: rbST treatment exerted its galactopoietic action more by local intramammary factors than by other extramammary factors at a low AT and the synergistic effect between rbST treatment and low AT increased the availability of intramammary glucose transport in activating the process of lactose synthesis.

Milk protein is well accepted for nutritional value compared with other sources of protein. Detailed understanding of the natural factors that can determine milk protein subcomponent (i.e., casein) not only fulfill the knowledge of protein synthesis but also provide the potential idea to improve milk quality. The variation in milk protein content from dairy cows and goats fed in tropical areas may determine the added value of milk from this region. Under prolonged high ambient temperature (HTa), dairy cows and goats are at the stage of heat stress. This physiological condition produces a negative effect on dairy cows and goats, i.e., food intake and milk yield. However, the higher milk protein content during summer is demonstrated in dairy goats in our condition. Likewise, an increase in heat shock protein 70 (Hsp70) gene expression from mammary epithelium cells isolated from either in vivo (summer and winter periods) and in vitro conditions suggests the direct effect of HTa on mammary gland and perhaps on milk protein synthesis. The intracellular effect of Hsp70 on milk protein synthesis has been proposed in regard to the endoplasmic reticulum and Golgi apparatus protein transportation and with the subcomponent of casein micelle. The present information reveals the molecular mechanism of HTa on milk protein synthesis.

Background and Aim: The high salinity of drinking water has been a significant problem of the Mekong Rivers Delta. Animals drinking high salinity water altered feed and water intake (WI), urinary electrolytes excretion, and productivity. This study aimed to evaluate the effects of high salinity in drinking water on drinking and eating behaviors and kidney function in crossbred goats. Materials and Methods: The experiment was completely randomized with two treatments: freshwater (0%, seawater [SW0]) and water high in salinity (1.5%, SW1.5) from diluted SW, with five replicates (five animals per treatment). This experiment lasted 3 weeks: the 1st week for the pre-treatment period and the 2nd-3rd weeks for the post-treatment. Dry matter intake (DMI) and WI were recorded every day, while urine volume (UV) was determined from day 8 to day 21. Blood and urinary samples were collected on days 6, 14, and 21 of the study for electrolytes and creatinine analysis. Results: The results demonstrated that both DMI and WI were affected by SW1.5 (p0.05), the weight gain observed in the SW1.5 group tended to decrease (p=0.056) at the 2nd week. The concentration of electrolytes in blood did not differ between the groups (p>0.05). In contrast, the concentration and excretion of Na+ and Cl- in urine increased in SW1.5 goats at D14 (p0.05). Conclusion: The study concluded that crossbred male goats can tolerate 1.5% saline water from diluted SW for 2 weeks. The high salinity in water influences drinking and eating behavior in growing goats. However, the adaptive mechanism by increasing urine output and reducing the reabsorption of Na+ and Cl- in the kidney is the key function and works faster than behavioral responses. The kidney apparently drives drinking behavior during high salinity water consumption.

Objective: This study was carried out to determine the effects of elevated dietary cation and anion difference (DCAD) on dry matter intake (DMI) and ruminal fermentation pattern in lactating dairy goats under tropical conditions.Methods: Ten dairy goats were divided into two groups of five animals each. The groups received diets at different DCAD levels, either a control diet (22.81 mEq/100 g dry matter [DM], DCAD-23) or a DCAD-39 diet (39.08 mEq/100 g DM, DCAD-39). After parturition, DMI and water intake were recorded daily. Ruminal fluid and urine were collected, and nutrient digestibility measurements were carried out at 8th weeks postpartum (PP-8). Blood samples were collected at PP-4 and PP-8 to measure plasma leptin.Results: Dry matter intake/body weight (DMI/BW) at PP-8 of the animals fed the DCAD-39 diet was significantly higher than those fed with DCAD-23 diet (p

OBJECTIVE The present study was carried out to evaluate the effect of high dietary cation and anion difference (DCAD) rations on diurnal variations in eating and meal patterns, water intake and urination patterns in dairy goats fed under high ambient temperature (HTa). METHODS Ten crossbred dairy goats during peri-parturition period were selected and divided into two groups of five animals each. Experimental diets were control DCAD (control, 22.8 mEq/100 g dry matter [DM]) and high DCAD (DCAD, 39.1 mEq/100 g DM). The composition of two diets consisted of 44% corn silage and 56% concentrate. From the 2nd week to 8th week postpartum, goats were fed ad libitum twice daily either with the control or DCAD total mix ration with free access to water. The spontaneous eating and drinking patterns were determined. RESULTS The environmental conditions in the present experiment indicated that goats were fed under HTa conditions (average peak THI = 85.2) and were in heat stress. In addition to the typical HTa induced tachypnoea in both groups, the respiratory rate in the DCAD group was significantly higher than the control group (p

Background and Aim: Metabolism and environment are closely related. Under high ambient temperature (HTa), dairy cows may have different energy metabolism during summer and winter. The present study was carried out to investigate the effect of HTa on the milk yield and blood concentration of beta-hydroxybutyrate (BHBA) and glucose at the herd level. Materials and Methods: One large dairy farm in Thailand with more than 100 crossbred Holstein cows milked each month was selected. The first experiment was performed on non-lactating cows to determine the normal daily concentrations of blood BHBA and glucose. Under the HTa condition, there was no significant change in blood BHBA and glucose concentrations. The second experiment was performed using a prospective cohort clinical design to demonstrate the seasonal effect on milk yield and blood BHBA as an indication of energy metabolism at the herd level. Results: The temperature and humidity index for the winter (78.1±0.5) and summer (83.4±0.7) periods differ significantly. The average milk yield during the winter period was 17.8% higher than during the summer period. The reduction of body condition score (BCS) during early lactation was significant in the winter cows. Both higher milk yield and lower BCS in the winter cows suggested a state of negative energy balance. However, there was no difference in blood BHBA and glucose concentrations between winter and summer cows. The effect of HTa on insulin signaling appeared to be a counterbalancing factor for the ketogenic status. Based on the present results, it would be interesting to further investigate the incidence of subclinical and clinical ketosis in a dairy farm under tropical conditions. Conclusion: The present experiment revealed that HTa during summer decreased milk yield in dairy cows fed under tropical conditions. Higher milk yield in winter caused a greater reduction of BCS and suggested a greater negative energy balance. However, there was no seasonal effect on blood BHBA and glucose concentrations.

The objective of the present study was to determine the factors that influenced growth performance of the goat kids of Black Bengal (BB), Saanen (SA), and their crossbred F1 (male Bengal × female Saanen [BBSA] and male Saanen × female Black Bengal [SABB]). Data for 674 kids were analyzed from 316 litters and 134 does. All kids were weekly measured on their characteristics (body weight, length, height at the withers, and chest girth) from birth to 11 weeks old. The kid's breed and sex, litter size, and season of kidding influenced birth weight and other characteristics through the experiment. The SA and BBSA kids showed similar performance, which were higher than BB and SABB kids. Male kids had higher performance than female kids, and kids from a single litter showed the highest performance. Kids born during rainy season showed lower performance than those born in hot and cool seasons. In conclusion, the crossbred BBSA is superior to SABB or BB to raise in tropical climate Moreover, sex, litter size, and kidding season also affected growth performance during the preweaning period up to 11 weeks old.

The mammary gland is a privileged organ for mammals. Because of their high capacity for milk synthesis, dairy ruminants have been distributed throughout the world. In tropical areas, dairy animals face high ambient temperatures (HTa). The indirect effect of HTa on milk synthesis is mediated in part by a reduction in feed intake. The current experiment focused on the direct natural effect of HTa on mammary function. Multiparous Saanen goats were used in this study. The physiological responses for HTa were evaluated from the control period during the winter and from the natural HTa during the summer. Milk samples were collected for isolation of the goat milk cells to study the expression of the β-1,4 galactosyltransferase (β-GALT1), Akt, and heat shock protein 70 (HSP70) genes. Although goats in the summer maintained rectal temperature and plasma cortisol levels similar to those observed in the winter, the higher respiratory rate and lower feed intake and milk yield (MY) from the goats in the summer indicated that the goats in the summer were exposed to a higher degree of HTa. This was supported by the significantly higher level of plasma glutathione peroxidase (GPX) activity. Moreover, the relative expression levels of β-GALT1 and Akt were not different. The relative expression of HSP70 during the summer was significantly higher than what was observed in cells isolated in the winter. In conclusion, the HTa effect on MY during the summer was related to its indirect effect on feed intake. The direct HTa effect might be related to HSP70 gene expression in goat milk cells and to plasma GPX activity. However, the natural HTa did not affect the expression of Akt or β-GALT1.

In general, goat mammary epithelial cells (MECs) are cultured in vitro under 37 °C. We demonstrated previously that goat MECs differentiate under 37 °C although their body temperature is approximately 39 °C. This study aimed to investigate the influence of 39 °C on lactogenic differentiation of goat milk-derived MECs. The results revealed that HSP70 gene was significantly elevated at 1 h after an exposure to 39 °C but declined at 48 h thereafter. Oxidative stress status was not significantly affected by 39 °C. Expressions of CSN2, β-GALT1, α-LA, and Akt genes tended to increase after the differentiation under 39 °C. Secretion of lactose under 39 °C was not significantly lower than 37 °C. In conclusion, incubation temperature at 39 °C does not dramatically affect lactogenic function of goat milk-derived MECs.

High ambient temperature (HTa) is an important environmental factor influencing food intake (FI). We previously demonstrated that low-degree HTa exposure decreased FI earlier than activated physiological responses, and this effect was related to the median preoptic nucleus (MnPO) and arcuate nucleus (Arc) connection. The present study refines the condition of low-degree HTa exposure and focuses on the mechanism of Arc neural activation. We demonstrated in the first experiment that with the usual ambient temperature (Ta) at 23 °C, the low degree HTa condition is at a 7 °C temperature difference and with 90 min exposure. Rats exposed to this short-term low-degree HTa had significantly lower 1-h FI than those exposed to control Ta (CTa) without differences in rectal temperature and hematocrit. Under nonfeeding conditions, HTa could enhance c-Fos at the Arc without the activation of proopiomelanocortin (POMC) neurons. Under feeding conditions, HTa could enhance both c-Fos and POMC at Arc. In addition, the number of c-Fos and POMC colocalizations in the HTa group was higher than that in the CTa group. Finally, intracerebral preinfusion with a subthreshold dose of the melanocortin antagonist SHU9119 reversed the effect of low-degree HTa exposure on FI. Therefore, we conclude that the effect of short-term low-degree HTa exposure on FI in rats is mediated in part by activation of POMC neurons at the Arc. The results partially support the hypothesis that Arc is a crucial hypothalamic nucleus for the effect of low-degree HTa exposure on FI.

Background Plasma leptin is regulated by several factors, including growth hormone (GH), which influences the pathophysiology of obesity. Objective To demonstrate the short-term effect of GH on plasma leptin levels in 3 conditions in vivo with the different amount of body fat mass. Methods Adult male Wistar rats were fed with standard chow or hypercaloric diet (HC). The HC rats were demonstrated as HC-feeding obese (HC-O) and HC-feeding resistant (HC-R) rats. Then, they were treated with GH or saline for 3 days. Basal plasma leptin levels were measured at 24 and 32 h. For meal-induced condition, all rats were fed for 2 hand plasma leptin was measured. Further 16-h fasting period, plasma leptin, insulin, and insulin sensitivity indexes were determined. Results The short-term GH treatment decreased basal plasma leptin at 32 h after the first GH injection in HC-O rats. However, GH treatment had no effect on meal-induced plasma leptin in all rats. Furthermore, GH treatment attenuated fasting effect on plasma leptin in control and HC-R rats. The insulin resistance (IR) induced by the short-term GH treatment was demonstrated by higher fasting plasma insulin and the increased homeostasis model of IR in HC-R rats. Conclusions The study demonstrates the important role of greater fat mass in HC-O rats, which results in decreased basal plasma leptin after short-term GH treatment. For meal-induced condition, GH had no effect on plasma leptin in all rats. Interestingly, GH could attenuate fasting effect on plasma leptin in rats that have lower fat mass.

High ambient temperature (HTa) activates both behavioral and autonomic responses. Decreased food intake (FI) is a well-known behavioral response under HTa. In general, this behavioral response seems to be mediated under the activation of the stress axis. The present study, however, revealed that decreased FI after a low degree of HTa appeared to be activated earlier than stress axis activation. By comparing low and high levels of HTa exposure in rats, the present experiment demonstrated that the HTa-induced decrease in FI was clear in both conditions. However, only the high degree HTa rats showed prominent physiological responses to HTa. The results indicated that low degree HTa exposure decreased FI earlier than activated physiological responses. Using the low degree HTa condition, the next experiment revealed that only the median preoptic nucleus (MnPO) and arcuate nucleus (Arc) were activated. These results suggested that the MnPO and Arc (MnPO-Arc) are apparently involved in the low degree HTa effect on FI and that the paraventricular hypothalamic nucleus, which is the upper part of the stress axis, was not associated with this effect. A separate experiment also showed no differences in the corticotropin-releasing factor (CRF) concentrations from many selected nuclei. This result suggested that the effect of HTa to decrease FI via the MnPO-Arc was not associated with CRF. The current findings introduce a new behavioral aspect of the HTa effect on FI, representing important information to explain the mechanism of obesity relative to environmental conditions.

This study aimed to determine the effect of dietary cation and anion difference (DCAD) on milk production and body fluid distribution in lactating dairy goats. Ten dairy goats were selected and divided into two groups, five animals each. Animals received either control DCAD (control, 22.81 mEq/100 g dry matter (DM)) or high DCAD (DCAD, 39.08 mEq/100 g DM). The results indicated that rectal temperature (Tr), respiration rate, milk yield and compositions did not differ between groups. But the percentage change of Tr from the DCAD group was lower than the control group between 09.00 and 13.00 hours. DM intake tended to increase in the DCAD group. Dairy goats in the DCAD group drank more water, but urinary excretion and plasma antidiuretic hormone concentration remained unchanged. Apparent water balance was higher from the DCAD group over 24 h. There was no effect of DCAD on plasma and blood volumes, but tended to increase in extracellular fluid and thereby increased total body water. The present results indicate that animals supplemented with high DCAD increase their total body water and apparent water balance. These results have contributed to the process of adaptation for evaporative cooling and would be useful in slowing down the elevation in Tr.

Estradiol (E2) inhibits eating behavior in females via activating estrogen receptors (ERs) within the brain. Activation of hindbrain ERαs has been shown to be sufficient to inhibit eating behavioral pattern. To investigate the involvement of hindbrain ERαs in estrogenic control of eating behavior, intracerebroventricular infusion (4th i.c.v.) of an estrogen receptor antagonist, ICI 182780 (ICI), was performed in ovariectmized female rats. Significantly lower daily food intake was observed in rats after estradiol benzoate (EB) injections. The effect of EB on food intake was significantly compromised by 4th i.c.v. infusions of both 4 and 8 nM ICI solutions. The results suggest that hindbrain infusions of ICI can significantly attenuate the inhibitory effect of E2 on food intake. Importantly, 4th i.c.v. infusions during 12 days exerted no effect per se on eating. Further, there was no difference in the number of ERα immunopositive neurons in the selected hypothalamic nuclei and nucl. tractus solitarius. We conclude that the 4th i.c.v. infusions with ICI attenuated the exogenous estrogenic effect on food intake in ovariectomized rats, and the hindbrain is an important site pro viding estrogenic control of food intake.

Objective: The aim of the present study was to investigate the beneficial effects of dietary supplementation with oil palm frond (leaf) (OPF) with and without oil palm meal (OPM) on nutrient intake and digestibility, ruminal fermentation and growth performance in goats.Methods: Six female crossbred goats were fed for 28 days of 3 diet treatments; 100% paragrass (T1); 50% para-grass + 50% OPF (T2), and 30% para-grass + 50% OPF + 20% OPM (T3). Body weight, rectal temperature, respiratory rate, and urine volume, food intake, dry matter intake and water intake were measured daily. Nutrient digestibility was determined from five consecutive days of last week in each diet. Ruminal fluid, urine and blood were collected at the end for determination of rumen protozoa and volatile fatty acid contents, urinary allantoin excretion, blood cell count and chemistry profiles.Results: Goats fed T2 and T3 showed higher dry matter and nutrients intakes while protein digestibility was suppressed compared with those for T1. Crude fat digestibility declined in T2 but maintained after adding the OPM (T3). High fat intake by giving OPF and OPM corresponded to a higher ruminal acetate/propionate ratio (C2/C3) and serum cholesterol level. An increased urinary allantoin/creatinine ratio was found in T2 and T3 compared with T1, implying an increased number of ruminal microbes.Conclusion: Increased dry matter intake in T2 and T3 suggested that oil palm by-products are partly useful as a replacement for para-grass in goats. Replacement with the by-products increased plasma cholesterol level, which suggested that these products are a useful energy source. Changes in rumen parameters suggested an increased microbial number and activity suitable for acetate production. However, the limited digestibility of protein implies that addition of high protein feeds may be recommended to increase body weight gain of goats.

The present study aims to investigate the composition including concentrations of IGF-1, IgG and Vit A in colostrum and their effects by litter size and goat parity in 3 groups of goats, Black Bengal (BB), Saanen (SA) and their crossbred (BBSA). Thirty-eight goats were used (23 BB, 7 BBSA and 8 SA). The composition (fat, protein, lactose and total solid, TS) in colostrum (Day 0, D0) and milk (Day 4, D4 and Day 7, D7) were measured. The IGF-1, IgG concentrations were analysed in some samples collected at D0, D4 and D7 while Vit A was analysed only in colostrum. The results showed that colostrum components were similar among experimental groups. However, the colostral IGF-1 concentration of BBSA (983.0 ± 163.6 ng/mL) was higher than that of BB (340.7 ± 85.5 ng/mL, p &lt, 0.01) and SA (417.1 ± 93.9 ng/mL, p &lt, 0.01). The colostral IgG concentration of BB (8.2 ± 0.9 mg/mL) was lower than that of BBSA (12.9 ± 1.7 mg/mL, p &lt, 0.05) and SA (12.9 ± 1.0 mg/mL, p &lt, 0.01). Colostral Vit A concentration in BBSA (787.2 ± 152.6 µg/100 gm) was higher than that in BB (388.9 ± 84.3 µg/100 gm, p &lt, 0.05) but was not different from SA (522.8 ± 96.9 µg/100 gm). Colostrum from all groups contained higher protein and TS but was lower in lactose concentration than milk. The IGF-1 and IgG concentrations in colostrum were much higher than in milk both D4 and D7 (p &lt, 0.001). Additionally, litter size had no effects on colostrum contents but colostrum from goats with a higher parity number had higher IgG concentration. It is concluded that colostrum from BBSA may be superior when fed to BB newborn goats in terms of higher IGF-1, IgG and Vit A contents. Moreover, colostrum from goats with a high parity number contained more IgG content.

Recombinant bovine somatotropin (rbST) has been shown to increase milk yield in dairy goats, especially during late lactation. The galactopoietic effect of rbST appears to derive mainly from the partitioning of nutrients to the mammary gland. Previously, this effect has been shown to coincide with an increase in feed intake. To test whether rbST has concomitantly an effect on milk yield and feed intake during the early lactation period, ten crossbred dairy goats during the peri-parturition period were selected and divided into two groups of five animals each. Two consecutive injections of sesame oil or rbST were performed at day 7 and 22 post-parturition (PP-7 and PP-22). Dry matter intake (DMI), water intake (WI) and milk yield of the individual animals were measured throughout the experiment. Blood was collected daily from day 6 post-parturition (PP-6) and throughout the first rbST injection period. Milk yield from the rbST supplemented group was slightly higher than the control group during the second rbST supplementation. Supplementation with rbST decreased significantly DMI per body weight. DMI digestibility from the second rbST injection did not differ between the treatments. The concentration of plasma IGF-1, insulin and glucose increased within 24 h after rbST injection. Importantly, plasma leptin also increased after rbST supplementation and this preceded the feed intake effect of rbST supplementation. The present results suggest that rbST induces a decrease in feed intake in dairy goats during early lactation, which relates to increase in the concentration of plasma leptin and in combination with galactopoietic effects of rbST, IGF-1 and insulin.

Eating is modulated by estradiol in females of many species and in women. To further investigate the estrogen receptor mechanism mediating this effect, ovariectomized rats and mice were treated with estradiol benzoate or the estrogen receptor-alpha (ER-alpha)-selective agonist PPT. PPT inhibited eating in rats much more rapidly than estradiol (approximately 2-6 h versus >24 h). In contrast, the latencies to vaginal estrus after PPT and estradiol were similar (>24 h). PPT also inhibited eating within a few hours in wild-type mice, but failed to inhibit eating in transgenic mice deficient in ER-alpha (ERalphaKO mice). PPT, but not estradiol, induced the expression of c-Fos in corticotrophin-releasing hormone (CRH)-expressing cells of the paraventricular nucleus (PVN) of the hypothalamus within 90-180 min in rats. Both PPT and estradiol reduced c-Fos expression in an ER-alpha-containing area of the nucleus of the solitary tract. The anomalously rapid eating-inhibitory effect of PPT suggests that PPT's neuropharmacological effect differs from estradiol's, perhaps because PPT differentially activates membrane versus nuclear ER-alpha or because PPT activates non-ER-alpha membrane estrogen receptors in addition to ER-alpha. The failure of PPT to inhibit eating in ERalphaKO mice, however, indicates that ER-alpha is necessary for PPT's eating-inhibitory action and that any PPT-induced activation of non-ER-alpha estrogen receptors is not sufficient to inhibit eating. Finally, the rapid induction of c-Fos in CRH-expressing cells in the PVN by PPT suggests that PPT elicits a neural response that is similar to that elicited by stress or aversive emotional stimuli.

The effects of long-term administration of recombinant bovine somatotropin (rbST) on glucose turnover and the utilization of glucose in the mammary gland using a continuous infusion of [3-3H]glucose and [U-14C]glucose in lactating crossbred Holstein Friesian(HF) cattle were investigated. Glucose turnover of rbST-treated animals was significantly higher than those of control animals (P

Effects of long-term treatment with recombinant bovine somatotropin (rbST) on concentrations of cellular metabolites in the milk of 87.5% crossbred Holstein cattle were performed. The peak milk yield of rbST-treated animals was 22% higher (P < 0.05) than that of the control animals in early lactation. The mammary glucose uptake of rbST-treated animals increased in early lactation, but decreased in mid and late lactation, while plasma glucose concentrations were not affected. Lactose and milk triacylglycerol secretion of rbST-treated animals significantly increased (P < 0.05) when compared with those of control animals in early lactation. The concentrations of milk glucose of rbST-treated animals significantly increased in early and mid-lactation (P < 0.05). The concentrations of milk galactose markedly increased (P < 0.05) whereas the concentrations of milk uridine 5'-diphosphoglucose (UDP-glucose) and UDP-galactose showed no significant changes as lactation advances in both groups. The concentrations of isocitrate, 2-oxoglutarate and citrate in milk from both groups showed no significant changes throughout experiment. The concentration of glucose-6-phosphate (G6P), glucose-1-phosphate and cyclic adenosine 3,5'monophosphate in milk from both groups markedly decreased as lactation advances exception in early lactation of rbST-treated animals, which G6P was not affected. These findings suggest that prolonged rbST treatment exerts its galactopoietic action at least in early lactation through both intramammary and extra-mammary changes. Increases in the concentrations of glucose and G6P in milk maintained the level of pretreatment in early lactation associated with increases in milk yields during rbST administration, reflect their concentrations in the cytosol or Golgi vesicles of mammary cells, which would be one of the factors regulating intermediary metabolites in the lactose biosynthetic pathway.

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

Experiments were performed to examine the effects of long-term treatment with recombinant bovine somatotropin (rbST) on milk plasmin–plasminogen and milk composition by one injection of 500 mg of rbST in every 14 days throughout lactation in crossbred Holstein cattle. The animals receiving rbST gave a greater milk yield and rate of blood flow to the udder during early lactation than the control group. The milk lactose concentration remained constant while the milk protein concentration increased as lactation advanced in both groups. The level of milk fat in rbST-treated animals was significantly greater than in controls in the early lactation period (P

Blood pressure (BP) was measured in 31 renal azotaemic dogs by oscillometric measurement at the posterior tibia artery, and urine and blood samples were collected. Haematology, blood chemistry and urinalysis were performed and urinary protein:creatinine ratio (UPC) and fractional excretions of electrolytes (FE(e)) were calculated. The results showed that only 19% of dogs with renal azotaemia were hypertensive, whereas almost all of them had high urinary protein and electrolyte excretions. There was no association between BP, UPC and FE(e). A positive correlation was found between all pairs of electrolyte fractional excretions. When the severity of renal impairment was observed using plasma creatinine concentration, neither BP nor UPC was correlated. Only the FE( e ) was associated with the degree of azotaemia. The results suggest that dogs with renal azotaemia do not necessarily have hypertension. The fractional urinary excretion of electrolytes may be a good indicator for severity of renal dysfunction in azotaemic dogs.

The objective of the study was to determine the in vivo relationship between the long-term administration of recombinant bovine somatotropin (rbST), circulating levels of IGF-I and insulin, mammary blood flow and other variables relevant to milk synthesis, in crossbred, Holstein cattle. Ten first-lactation, non-pregnant, crossbred, Holstein dairy cattle were divided into two groups of five animals each; an experimental group and a control group. Animals in each group were fed with rice straw, treated with 5 kg urea dissolved in 100 litres water per 100 kg dry rice straw as the source of roughage. Four consecutive study periods were carried out in each group. These consisted of a pretreatment period (45 days postpartum before lactation peak) and three treatment periods during early lactation (105 days postpartum), mid-lactation (165 days postpartum) and late lactation (225 days postpartum). During the treatment periods, animals that had completed 60 days of lactation were injected subcutaneously at fortnightly intervals with 500 mg of recombinant bovine somatotropin (rbST) (POSILAC, Monsanto, USA) in the experimental group, while animals in the control group were injected subcutaneously at fortnightly intervals with 800 mg of sterile sesame oil, without rbST, as a placebo. During the pretreatment period, there were no significant differences in plasma concentrations of IGF-I, insulin and other parameters between the control group and the experimental group. During the treatment periods, the increase in the concentration of plasma IGF-I in rbST treated animals was significantly higher than in the control animals throughout the lactation period. Plasma glucose, protein and triglyceride concentrations in each group remained stable throughout the study. The total daily dry matter intakes were not significantly different between the groups. Milk yield increased by 20% with rbST treatment and it was 22% greater than that of the control animals receiving placebo in early lactation. Milk yield of rbST treated animals rose to a peak in early lactation and then gradually declined. In late lactation, milk yield of rbST-treated animals decreased by 19% as compared with early lactation. Udder plasma flow and udder blood flow markedly increased with rbST treatment and there were no significant changes in the control animals. The ratio of udder blood flow to the rate of milk production increased in mid- and late lactation in controls and the rbST treated animals. These findings suggest that the short persistency of lactation in rbST treated animals was similar to that in the control animals receiving placebo. Changes in milk production during the progress of lactation in rbST treated animals might not be controlled systemically only but also locally within the mammary gland. The lack of effect of higher plasma IGF-I levels on persistency of lactation in rbST treated animals, may be due to changes in the pattern of IGF-I binding proteins and paracrine production inhibiting IGF-I action.

The objective of the present study was to determine the plasma level of insulin-like growth factor-I (IGF-I) in relation to mammary blood flow and milk yield including biological variables of relevance to milk synthesis in two different types of crossbred Holstein cattle at 3 different stages of lactation. Eight heifers were 87.5% HF and eight 50% HF animals were selected for the experiments. The three stages of lactation tested were: early lactation (30 days postpartum), mid-lactation (120 days postpartum) and late lactation (210 days postpartum). Animals in each group were fed a concentrate and rice straw treated with 5% urea as the source of roughage throughout the experiments. In early lactation, mammary blood flow and milk yield of 87.5% HF animals were significantly higher than those of 50% HF animals. In mid- and late lactation, both mammary blood flow and milk yield showed a proportional decrease from the early lactating period of 87.5% HF animals. The trends for persistency were observed in 50% HF animals as for udder blood flow and milk yield throughout the experimental periods. The plasma glucose level of the 50% HF animals was significantly higher than those of 87.5% HF animals in both early and mid-lactation. The concentrations of arterial plasma free fatty acids (C16 to C18) were higher in 50% HF animals as compared with 87.5% HF animals in all periods of study. In early lactation, the concentration of plasma growth hormone (GH) of 87.5% HF animals was higher than those of the 50% HF animals, thereafter the mean level of plasma growth hormone declined in both mid- and late lactation. The concentration of plasma IGF-I of 50% HF animals was significantly higher than those of 87.5% HF animals in all stages of lactation. There were no differences among stages of lactation for the levels of plasma IGF-I, insulin and growth hormone in 50% HF animals. In 87.5% HF animals, the plasma levels of both IGF-I and insulin were lower in early lactating period while it showed an increase during mid- and late lactation. The present results indicated that the regulatory role for the higher mammary blood flow and milk yield during lactation in 87.5% HF are not mediated via the higher level of circulating IGF-I. Differences in mammary blood flow and milk yield between 50% HF and 87.5% HF animals are in part due to a higher concentration of circulating growth hormone. The lower level of circulating growth hormone in 50% HF animals would be regulated by higher levels of IGF-I, free fatty acid and glucose in plasma. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 3 : 343-348)

The present experiment was carried out to study the utilization of substrates in the mammary gland of crossbred Holstein Friesian during feeding on different types of roughage. Sixteen pregnant crossbred Holstein heifers consisted of two breed types of eight animals each; Holstein Friesian×Red Sindhi (50:50=50%HF) and Holstein Friesian×Red Sindhi (87.5:12.5=87.5%HF). Animals were divided into four groups of the same breed type in each group which were fed with either rice straw treated with 5% urea or pangola hay (Digitaria decumbens) as the source of roughage throughout the experiments. Four consecutive experimental periods were carried out in late pregnancy (20-23 days before parturition), early lactation (30 days postpartum), mid-lactation (120 days postpartum) and late lactation (210 days postpartum). Measurement of mammary blood flow in combining with measurement of AV difference was performed for the mammary uptake of substrates. In the period of lactation, udder blood flow was nearly three times higher than that of late pregnant period (p