No abstract

Active immunization against infectious disease is important. However, much of our world faces poverty, social injustice, and warfare, all of which cause universal immunization to remain a distant dream. Agents that provide passive immunity thus remain essential biologicals. The most important of these are human or equine antisera against rabies, tetanus, diphtheria, and snake antivenins. Homologous products are either unavailable or unaffordable in places where they are needed the most. Less expensive heterologous (equine) antisera can be purified and are safe to use, but these antisera are also in short supply. Monoclonal antibodies have been developed but are even less likely to be affordable in poor countries. Several traditional sources of equine antisera are becoming depleted as a result of economic disincentives; a poor reputation based on the high adverse reaction rates of the old, unpurified products; and the activities of animal rights activists who object to the use of horses as blood donors. Purified, pepsin-digested equine antisera are preferred; but developing countries sometimes are forced to make crude products that are less safe or have no specific therapy available at all.

The aim of this study was to determine how evaporative cooling modifies body function with respect to water metabolism and other variables relevant to milk synthesis in crossbred cattle. The study was conducted on two groups of 0.875HF:0.125RS crossbred Holstein cattle (87.5%) housed in an open-sided barn with a tiled roof (non-cooled animals) and in a close-sided barn under an evaporative cooling system (cooled animals). The maximum ambient temperature and relative humidity for the non-cooled group were 33 degrees C and 61%, with the corresponding values for the evaporatively cooled barn being 28 degrees C and 84%, respectively. The temperature humidity index (THI) of under non-cooled conditions was higher (P < 0.05) than that in the cooled barn. Rectal temperatures and respiration rates of non-cooled animals were higher (P < 0.05) than those of cooled animals. Daily dry matter intake (DMI) of cooled animals was higher while water intakes were lower (P < 0.05) than those of non-cooled animals. The mean absolute values of plasma volume, blood volume, and extracellular fluid (ECF) of cooled animals were significantly higher (P < 0.05) than those of non-cooled animals throughout all stages of lactation. Milk yields of cooled animals were higher by 42%, 36% and 79% on average than those of non-cooled animals during early-, mid- and late-lactation, respectively. The decline in milk yields as lactation advances was markedly apparent in late-lactating non-cooled animals, while no significant changes in milk composition at different stages of lactation were observed in either group. Mean arterial plasma concentrations, arteriovenous concentration differences (A-V differences) and the extraction ratio across the mammary gland for acetate, glucose and triglyceride of cooled animals were not significantly different compared with values for non-cooled animals. No differences were seen in plasma hormonal levels for triiodotyronine (T(3)) and insulin-like growth factor-1 (IGF-1), but plasma cortisol and thyroxine (T(4)) levels tended to be lower in non-cooled animals. This study suggests that low cooling temperature accompanied by high humidity influences a galactopoietic effect, in part through increases in ECF, blood volume and plasma volume in association with an increase in DMI, which partitions the distribution of nutrients to the mammary gland for milk synthesis. Cooled animals were unable to maintain high milk yield as lactation advances even though a high level of body fluids was maintained during long-term cooled exposure. The decline in milk yield, coinciding with a decrease in net energy for lactation as lactation advances, could be attributed to a local change within the mammary gland.

No abstract

Summary The present study was carried out to evaluate the effect of prolonged feeding of urea‐treated rice straw, compared with feeding of hay, on the regulation of body fluids, milk yield and mammary circulation at early lactation (30 days postpartum), mid‐lactation (120 days postpartum) and late lactation (210 days postpartum) in crossbred Holstein Friesians. Sixteen first lactating crossbred Holstein Friesians (HF), consisting of eight animals of two breed types, 87.5%HF and 50%HF, were selected and each breed was randomly allocated into two groups. Each group, consisting of four animals from the same breed, was fed either 5% urea‐treated rice straw or pangola hay (Digitaria decumbens) as the source of roughage in combination with a similar concentrate throughout the experiments. During the course of lactation there were no significant differences in body weight, heart rate, mean arterial blood pressure, plasma osmolality, plasma volume and blood volume among groups of 87.5%HF animals and 50%HF animals fed either hay or urea‐treated rice straw. Water turnover rate, total body water space and total body water as a percentage of body weight of 50%HF animals were significantly higher than those of 87.5%HF animals fed either hay or urea‐treated rice straw. The packed cell volume was significantly higher in all lactating periods of both groups of 50%HF animals in comparison with 87.5%HF animals. The ratio of DM intake to milk production for 87.5%HF animals fed either hay or urea‐treated rice straw was significantly lower than that of 50%HF animals in early lactation. The udder blood flow and milk secretion of 87.5%HF were significantly higher in early lactation and markedly declined when lactation advanced in comparison with those of 50%HF animals fed either hay or urea‐treated rice straw. The ratio of mammary blood flow to milk yield for all groups was in a similar range during early lactation although it significantly increased in mid‐ and late lactation for both groups of 87.5%HF animals. From these results it can be concluded that both 50%HF and 87.5%HF animals feeding on urea‐treated rice straw as a roughage source do not show any undernutritional effects in comparison with those fed with hay during the course of lactation. The physiological response differences between breeds are that 87.5%HF animals, which have a genetic makeup closer to the exotic bos taurus breed and a high milk yield, show a poor adjustment to the tropical environment and poorer lactation persistency in comparison with 50%HF animals.

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.

549Effects of acute heat stress on changes in the rate of liquid flow from the rumen and turnover of body water of swamp buffalo SUMMARY During 5 h of acute heat exposure (41 °C), there were increases in the heart rate from 43±2 (S.E.) to 51 ± 1 beats/min, respiratory rate from 26±4 to 86± 16 breaths/min and rectal temperature from 385 + 0 1 °C to 39-7 + 0-2 °C. The flow rate of liquid from the rumen and body water turnover significantly increased while biological half life of ehromium-51 ethylenediaminetetra-acetate in the rumen and tritiated water decreased from 12-9±2-5 and 87-7 + 6-8 h to 9-3±20 and 49-2±5

Summary In this study, 16 pregnant crossbred Holstein Friesian (HF) heifers, consisting of eight animals of two breed types, 87.5%HF and 50%HF were selected and each breed was randomly allocated into two groups. Each group, consisting four animals from the same breed, was fed either 5% urea treated rice straw or pangola (Digitaria decumbens) hay as the source of roughage. Animals from each breed type were maintained on the ration in combination with a similar concentrate throughout the experiments. Two consecutive periods of experiments were carried out in each groups. Period 1 was designed to begin 21 days before parturition (late pregnancy) and period 2 began 30 days postpartum (early stage of lactating period). The body weight of the 87.5%HF animals fed either hay or urea treated rice straw significantly decreased in the early stage of lactation when compared with the late pregnant period. The body weight of 50%HF animals did not change significantly. The water turnover rate was significantly higher in lactating animals than in pregnant animals in all groups. During the lactating period the half‐life of tritium was significantly lower than during the pregnant period. There were no significant differences in the water turnover rate among groups of animals in regard to either the pregnant period or lactating period. In the lactating period significant reductions of total body water were noted in both groups of 87.5%HF animals fed either hay or treated rice straw, while this was not apparent for 50%HF animals. Plasma volume and blood volume increased significantly in the lactating period when compared with the pregnant period in all groups. The packed cell volume significantly decreased in the lactating period of both groups of 87.5%HF animals while it did not significantly change in 50% HF animals. The packed cell volume of 50% HF animals was significantly higher than that of 87.5%HF animals fed either hay or treated rice straw. There were no significant differences in heart rate, arterial blood pressure and plasma osmolality between the periods of late pregnancy and early stage of lactation in all groups of animals. Udder blood flow was nearly three times higher in lactating animals than in late pregnant animals in all groups. The udder blood flow of 87.5%HF animals was significantly higher while mammary resistance was significantly lower than in 50%HF animals. Milk secretion of 87.5%HF animals fed either hay or treated rice straw was significantly higher than that of 50%HF animals. The ratio of udder blood flow to milk secretion ratio was in the similar range for all groups of experimental animals. The ratio of dry matter intake to milk production for 87.5%HF animals fed either hay or urea treated rice straw was significantly lower than that of 50% HF animals. From these results it can be concluded that no differences in physiological functions are apparent for prolonged feeding of urea treated rice straw or pangola hay in the same crossbred pregnant and lactating animals. The difference between breeds is foun...