Bovine lipoprotein and apolipoprotein profiles as influenced by sex and growth.

Three (intact) Angus males and females that were half-sibs and born within 21 d of each other were selected for this study. Each animal was bled periodically from birth to slaughter (18 mo) to determine the qualitative composition of plasma lipoproteins and apolipoproteins during its growth and development. Major components observed were: 1) very low-density (VLDL), 2) low-density (LDL), and 3) high-density lipoproteins (HDL). Individual amounts of triglycerides, cholesterol, and proteins for the VLDL were not different (P greater than .05) between sexes at any time during growth and development. At 1 yr of age and 15 mo of age, females had significantly larger (143.4 and 93.5 mg/dl) amounts of protein in the HDL than males (67.0 and 93.5 mg/dl), respectively. Within the male group, the LDL triglyceride concentration of calves was significantly (P less than .05) higher (7.4 mg/dl) than at all other bleeding times. Within the female group, cholesterol values for the VLDL were significantly (P less than .05) larger as calves and weanlings (16.5 and 21.7 mg/dl respectively) than for other bleeding periods. At all stages of growth and development, the HDL apoprotein profiles showed a distinct band with a weight of about 28,000 Da, which represented apolipoprotein-A-I. During the suckling stage, pooling of LDL fractions provided two components on the acrylamide gel (7.5 to 20%), apolipoprotein-B and a low molecular weight band. At 12 and 15 mo, no low molecular weight band was present in the pooled LDL fraction.(ABSTRACT TRUNCATED AT 250 WORDS)