Relationships between fertility, serum calcium and inorganic phosphorus in dairy cows.

A prospective study was conducted to investigate the difference in levels of some blood constituents between fertile and infertile cows. A total of 40 dairy cows were selected at random from a dairy farm. Serum samples were collected three times on 5 ± 3, 30 ± 3 and 58 ± 3 days postpartum. Serum glucose, urea nitrogen (UN), cholesterol, albumin, total protein, calcium, inorganic phosphorus and aspartate aminotransferase (AST) were measured for each sample. Cows were divided into two categories; those which conceived at either the first or second insemination (group 1) and those which conceived =3 inseminations (group 2). Seventy percent (28 of 40) of the cows conceived at first or second insemination and 30% (12 of 40) needed 3 or more inseminations. Results showed that calcium (2.34 vs. 2.17 mmol/L) and inorganic phosphorus (1.84 VS. 1.42 mmol/L) were significantly (P 0.05) higher in the group I cows at second stage of sampling.