Field Investigation of Perinatal Mortality in Friesian Cattle Associated with Myocardial Degeneration and Necrosis

Abstract

Perinatal mortality and stillbirths were investigated in an extensively managed herd of Friesian cows and heifers calving over a 2-year period: 504 cows were calved and 215 heifers. Cows were bred to Friesian and Jersey bulls using natural service. The perinatal fetal mortality rate was 7.5% for cows and 30% for heifers. An experienced stockman managed these calvings and veterinary assistance was required only on nine occasions. All stillborn fetuses were examined post-mortem by the Veterinary Laboratories Agency, Carmarthen and no infectious agent was identified on any occasion. Thyroid hyperplasia was found in two fetuses. In blood samples taken from 10 late pregnant heifers, mean glutathione peroxidase values were 7.9 +/- 1.7 IU/ml Packed Cell Volume (PCV). Tissues from eight fetuses were submitted to the University of Liverpool for histopathological examination; all presented lesions consistent with myocardial degeneration and necrosis of the left ventricle. Following treatment of 205 late pregnant heifers with sodium selenite and vitamin E, the overall perinatal mortality rate in these cattle fell to below 11%.

Observations of brachygnathia superior (underbite) in wild ruminates in Western Montana, USA

“…Anomalies of reproductive organs are now recognized as being a worldwide problem in an unprecedented number of wild vertebrate species [39]. While direct causes are difficult to identify [9,40,41], the signs we found on wild and domestic species are consistent with those reported in experimental studies of congenital hypothyroidism in ungulate species [6,7,24,37,38].…”

“…Signs previously described for equine foals [1][2][3]6] and other species [7,8,24,34] with congenital hypothyroidism were nearly identical to those we found on necropsied fawns of white-tailed deer and mule deer, and on elk calves, beef calves and newborn goats. Signs reported for bovines [35] include not only hypothyroid signs [36], but also hyperplasia of the thymus [37] and myocardial degeneration and necrosis of the left ventricle [38]. Additionally, thymic aplasia [38] was found in another ruminant, newborn sheep, with experimentally induced congenital hypothyroidism [24].…”

“…Signs reported for bovines [35] include not only hypothyroid signs [36], but also hyperplasia of the thymus [37] and myocardial degeneration and necrosis of the left ventricle [38]. Additionally, thymic aplasia [38] was found in another ruminant, newborn sheep, with experimentally induced congenital hypothyroidism [24]. Many of the white-tailed deer fawns that had brachygnathia superior at birth also exhibited anomalous thymic and cardiac development, as well as other signs listed for congenital hypothyroidism [6,34], including contracted tendons and herniated umbilicus.…”

A review of the causes of poor fertility in high milk producing dairy cows

“…Perinatal mortality, within the first 48 h of parturition following a normal gestation is correlated with dystocia (>50%) and the incidence is increasing in some countries (Meyer et al, 2001;Berglund, 2008). Stillbirth rates vary between 6 and 8% for cows and 11 and 30% for heifers (Meyer et al, 2001;Murray et al, 2008) with feto-pelvic incompatibility probably the main cause of perinatal mortality in heifers. Inbreeding also contributes to a higher incidence of dystocia and stillbirth while crossbreeding can be used as a tool to alleviate its effects (Berglund, 2008).…”

Bovine abortion Part 1: Still one of the most difficult diagnoses to make

“…Myocardial degeneration may be associated with hypoxia itself, present for some hours before death: however, the fetus was stillborn which suggested this was not the case. Alternatively, such pathology has been associated with vitamin E/selenium deficiency in the fetus during the last third of pregnancy (Murray et al , 2008). The absence of any focal myocarditis suggested that this cow was not actively infected with N. caninum at the time of abortion and serology confirms this opinion.…”