Browsing by Author "Van der Merwe, H. J."
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- ItemAmino acid requirements of South African Mutton Merino lambs 3. Duodenal and whole empty body essential amino acid profile(South African Society for Animal Science, 1999) Ferreira, A. V.; Van der Merwe, H. J.; Loest, C. A.The duodenal and whole empty body essential amino acid (EAA) profile of South African Mutton Merino lambs fed a standard growth diet was investigated. The data of 20 lambs were used. With the exception of phenylalanine, significant (p < 0.05) differences between the EAA concentrations of the duodenal digesta and whole empty body occurred. From the chemical score, it was concluded that the duodenal digesta was first-limiting in histidine and second-limiting in methionine, followed by threonine and arginine for the whole empty body growth of South African Mutton Merino ram lambs fed a standard diet high in rumen degradable protein. A calculated essential amino acid composition for the correction of imbalances in duodenal digesta was as follows (%): 11.21 arginine; 14.53 histidine; 8.17 isoleucine; 9.97 leucine; 8.64 lysine; 13.87 methionine; 9.97 phenylalanine; 12.54 threonine and 11.11 valine.
- ItemEvaluering van die lesitien isfingomielien verhouding en die skuimtoets as fetale longmaturiteitstoetse(Health & Medical Publishing Group, 1978) Van der Merwe, H. J.; Cranna, E. J.The lecithin/sphingomyelin (L/S) ratio and the foam test to determine fetal lung maturity in order to prevent hyaline membrane disease (HMD) were used in 800 patients. The incidence of HMD in all neonates diminished from 3,25% in 1971, when the lung maturity test was not done, to 2,12% in 1975, the 4th year that such determinations were done. In the same period the incidence of respiratory distress syndrome (RDS) increased from 3,68% to 4,31%. Only 1% of fetuses in whom lung maturity was determined during the period 1972-1975 developed HMD. This reduced incidence of HMD is considered to be the result of prenatal determination of fetal lung maturity. No correlation was found between fetal lung maturity and length of gestation or physical condition of the neonate. The foam test results were compared with the L/S ratio, and a false positive figure of 8,3% and a false negative figure of 27,1% were found. It is recommended that the foam test be used for screening and the L/S determination be done only if the foam test is negative in high-risk patients.
- ItemNitrogen retention response to the abomasal infusion of amino acids in South African Mutton Merino lambs(South African Society for Animal Science, 2002) Ferreira, A. V.; Van der Merwe, H. J.; Fair, M. D.The nitrogen (N) retention response to the abomasal infusion of amino acids in South African Mutton Merino ram lambs fed a standard finishing diet was investigated. The basal diet consisted of (g/kg air dry weight): 300 lucerne, 80 wheat straw, 561.5 maize meal, 35 molasses meal, 10 urea, 5 salt, 7.5 ammonium chloride, 1.0 vitamin/mineral premix and 0.29 taurotec®. Twenty-eight lambs (ca. 38 kg live weight) were randomly allocated to four treatments consisting of different abomasal infusion rates of an amino acid mixture, formulated to contain essential amino acids in the same ratio as that of the whole empty body. The mixture consisted of (g/kg): 119.7 arginine, 154.9 histidine, 22.1 isoleucine, 106.5 leucine, 91.5 lysine, 146.9 methionine, 105.6 phenylalanine, 133.8 threonine and 118.7 valine. The mixture was infused at levels of (g/d): 0.00, 38.27, 51.02 or 63.78. Glycine was used to balance the various mixtures on an iso-nitrogenous basis. Infusion of 51.02 g/d of the essential amino acid mixture resulted in a significant increase in N retention, expressed as a percentage of N intake, compared to the control group which received the test diet and glycine (Phase 1). The omission of histidine, methionine or threonine from the infusate (Phase 2) had no significant decrease in N retention or plasma amino acid concentrations compared to the infusion of the mixture of nine essential amino acids.