Economic Losses Associated with Summer Mastitis in Pregnant and Non-Pregnant Heifers

Abstract

In Denmark, the economical losses associated with summer mastitis are mainly due to an irreversible destruction of lactating glands of heifers. In the present investigation we followed the fate of pregnant and non-pregnant Black-Pied Friesian heifers after their initial acute disease contracted while grazing on common grasslands in northern Jutland. For the pregnant heifer the average loss was 5,800 Dkr. (1984). This was primarily explained by a reduction in the expected milk yield due to early slaughtering resulting in a shortened lactation period due to failure of the affected gland to produce milk. For the non-pregnant heifer the average loss of 2,000 Dkr. (1984) was also mainly attributable to slaughtering at an early stage, i.e. 4 months (average) after the attack. In both categories of heifers, deaths, treatment costs, transport costs, etc. played a relatively insignificant part in the overall losses. The ongoing genetically-governed increase of performance was believed to be diminished by the unintended early removal of recruitment stock. Attempts were made to estimate losses at the herd level. Cost/benefit outcomes resulting from various preventive strategies were dependent on levels of incidence in the herd.