Nutritional parameters in the blood of dams during late gestation and immediately after calving, in the umbilical vein at calving, and in the blood of calves immediately following birth in Holstein heifers pregnant with either Holstein or beef breed fetuses

Abstract

Recently, the ratio of Holstein cattle receiving artificial insemination or embryo transfer from the Japanese Black cattle population has been increasing in Japan. The Japanese feeding standard for dairy cattle (National Agriculture and Food Research Organization[NARO], 2017) states that the nutritional requirements of dairy cattle pregnant with beef breeds are slightly higher than those of beef cattle pregnant with beef breeds; however, the differences between dairy cattle pregnant with similar dairy breeds and those pregnant with beef breeds are not discussed. In general, pregnant Japanese Black cattle receive individual management, whereas dairy cattle receive herd management. Therefore, dairy cattle are managed without considering fetal breeds, and the effect of this on fetal growth and nutrition is unclear.The main fetal nutrients for growth are glucose and amino acids (Bell & Ehrhardt, 2002;Nishida, 2009). During late gestation, reduced insulin sensitivity in peripheral tissues ensures adequate transfer of glucose from the dam to the fetus, which is an insulin-independent process (Hayirli, 2006). Placental glucose transfer is dependent on