Fertility in High Yielding Dairy Cows

Introduction Genetic progress coupled with improved nutritional management has resulted in many more cows that can produce over 8,500 litres per 305 day lactation. This upward trend in production over the past 30 years has been accompanied by a steady decline in fertility, with first service conception rates often falling below 40%. Over the same period, there have been considerable changes to dairy management systems in terms of increased herd size, reduced manpower and altered diets. The important question we need to answer is whether the drop in fertility is an inevitable consequence of increased yield? If not, a better understanding of the underlying causes may enable us to improve the management of modern Holstein cows to enable them to maintain an acceptable level of reproductive performance.