Effect of nutrition on fertility and blood composition in the milk cow.

The relationship between nutrition, fertility and blood composition was studied in 400 cows from commercial farms. Fertility evaluated by overall conception rate (OCR) was shown to be significantly related proportion of concentrate and roughage feeds in the diet, and to its content of dry matter, digestible protein, Ca and P. The ratio of serum total lipids to glucose and a newly introduced parameter, delta Pi (a calculated value, obtained by subtracting whole blood levels of Pi from those of the blood serum), showed a highly significant relationship to OCR. No significant relationship was found between OCR and serum, total lipids, cholesterol, urea, Ca, Mg, organic and inorganic phosphate. The values and significance of the 2 blood parameters which showed a relationship to fertility are discussed.