Volume 49 Supplement 1
Prenatal death in Icelandic cattle
© Benjamínsson; licensee BioMed Central Ltd. 2007
Published: 12 December 2007
Reasons for stillbirths among 1st. calving heifers
The effect of feeding on stillbirth rate
Effects of ensilageing on vit. E
Behaviour of cows around calving and stillbirth rate
Se fertilizer on cultivated grassland
Se fertilizer on barley
Genetic factors effecting stillbirth rate
The results of this project are expected to be presented and published in February 2008. The manager is Prof. Magnús B. Jónsson, at The Icelandic Agricultural University.
Effect of the sex of the calf, multiple birth (twins, triplets)
Effect of age at first calving
Length of gestation
Sire of calf
Effect of degree of inbreeding, both in dam and calf, 1st calving heifers only
Other factors that were examined but showed no significance were year of calving, region, herd size and average yield in herd.
There were large variations between the 801 herds in the study. The stillbirth rate ranged from 1.7% to 29.6%.
The gap between stillbirth rate for single-born bulls and heifers has been increasing during recent years. In 2004 the stillbirth rate for bulls was 17% while it was 13% for heifers .
In this investigation the effect of the sire of calf was huge. For sires with more than 50 recorded offspring, the stillbirth rate varied from <3% to >20%, although one has to take into account that A.I. bulls were used on the minority of virgin heifers in the period that data collection took place.
In the fall of 2004, a survey  was carried out among 70 farms with high (>25%, 55 farms) and low (<10%, 15 farms) stillbirth rates in calves in the period from 2000–2003. The aim of the survey was to investigate whether there were any differences in management practices on these two "types" of farms. In short there were no obvious differences, although the "low" farms tended more to use A.I. bulls on virgin heifers, so the expected calving data are better known there. The adaption period of the heifers in the cow herd was also longer on these farms. The housing for young stock also seemed better on these farms. Use of concentrates during the last month of gestation was little higher on the "high" farms, which could increase the risk of dystocia and therefore stillborn calves.
The same farmers as in the previous survey were asked to record calving procedures from August 2004 to January 2005. Survey forms were sent to 90 farmers: 27 of them filled out the forms, with information on 687 calvings. In this survey, 18.9% of the calves were stillborn.
No calving difficulties were recorded in 73.4% of calvings, 4.7% of the calves came backwards and calving difficulties due to very large calf was recorded in 6.7% of all calvings. Other reasons and unknown were roughly 15%.
In over half of the calvings no assistance was needed, or 55.5%. Slight assistance was given in 28.2% of calvings, much assistance in 11.6%, veterinarian assistance was given in 2.6% of calvings, and caesarian surgery was carried out on two cows, or 0.3%.
If the calves were stillborn, the farmers were asked to record the time of death: 7.1% of the calves were dead long before the calving, and beginning to rot; 40.9% of the calves had died in the last 24 hours before calving and 35.4% of them died during calving; 6.3% of them died in the first hours or days after calving, and in 10.2% of calvings the estimated time of death was not recorded.
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This article is published under license to BioMed Central Ltd.