The regulation of body fluids and mammary circulation during late pregnancy and early lactation of crossbred Holstein cattle feeding on different types of roughage

Abstract

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...

Control of Mammary Function During Lactation in Crossbred Dairy Cattle in the Tropics

“…The different control mechanisms were at play in the regulation of milk production as lactation advances in 50%HF and 87.5%HF cattle. The 87.5%HF cattle had lower efficiency in water retention mechanism and poor adaptation to tropical environment in comparison to 50%HF (Chaiyabutr et al, 1997;2000a). The high genetic similarity of 87.5%HF cattle to the exotic bos taurus breed may lead to poor adjustment to the tropical environment, while yielding high milk production in early lactation.…”

“…According to the study of Chaiyabutr et al, (1997) in measurements of water metabolism, the water turnover rate (WTO), total body water (TBW) in dairy cattle were performed using tritiated water dilution techniques. Briefly, the dairy cattle was injected intravenously with carrier free tritiated water in normal saline at a single dose of 3,000 µCi per animal.…”

“…Total body water (TBW) was calculated by using the corrected factor (1 -fraction of plasma solids) x TOH space (Chaiyabutr et al 1997).…”

“…The regulation of body fluids and mammary circulation in different types of crossbred Holstein Friesians (HF) cattle showed some differences between 50%HF and 87.5%HF cattle during late pregnancy and lactation (Chaiyabutr et al, 1997). A short persistency of milk yield during the transition period from early to mid lactation has been observed in 87.5%HF cattle.…”

Effects of Cooling and Supplemental Bovine Somatotropin on Milk Production relating to Body Glucose Metabolism and Utilization of Glucose by the Mammary Gland in Crossbred Holstein Cattle

“…Glucose kinetic studies were carried out by using continuous infusion of both [U-14 C]-glucose and [3-3 H]-glucose solution as described previously by Chaiyabutr et al (1998). Briefly, at about 10.00 h of the specified day, a priming dose of radioactive glucose in 20 mL of sterile NSS containing 30 µCi [ Mammary blood flow measurement: Blood flow through half of the udder were performed in duplicated by dye dilution technique using dye T-1824 (Evans blue) by a short term continuous infusion into the milk vein as described by Chaiyabutr et al (1997). The rate of blood flow through half of the udder was calculated from plasma sample and the value of packed cell volume using the equation derived by Thompson and Thomson (1977).…”