Investigating poor reproductive performance in suckler herds – are we missing a trick?

Profi tability of beef suckler herds is directly related to the number of calves reared per heifer or cow served annually. The economic consequences of high barren rates can, therefore, be very signifi cant, let alone the costs associated with the diagnosis and management of the problem causing poor fertility. In recent years, we have eradicated brucellosis, which used to be a major cause of reproductive losses, and many farms now also have disease control strategies in place for bovine viral diarrhoea (BVD), leptospirosis and bovine herpes virus type 1 (BoHV-1). However, reproductive disease caused either by other infectious, as well as non-infectious, causes are still commonplace. To effectively control reproductive losses, the precise root of the problem must be identifi ed and, since several diseases can cause similar signs, thorough veterinary knowledge and investigation is often required. The fi rst steps in the investigation of a suckler-herd fertility problem are to: • Review the herd’s reproductive history and analyse farm records where available, including the length of the breeding season, bull-to-cow details and pregnancy rates; • Assess female and male nutritional status, including information regarding body condition scoring, diet formulation and vitamin and mineral supplementation; • Assess reproductive health, including information from female reproductive tract examination and bull breeding soundness evaluations where available; • Conduct a biosecurity audit and assess herd health and vaccination status; and • Establish the presence or absence of associated clinical signs. After this, laboratory testing for infectious diseases can be conducted to establish whether or not there is evidence of recent exposure to infections such as BVD, leptospirosis or BoHV-1. However, when the results of these investigations are inconclusive or even eliminate all common differentials, sexually transmitted diseases, particularly bovine venereal campylobacteriosis (BVC), are worthwhile consideration.