Investigation of the causes of abortion and stillbirth in swine breeding herds
| Autor: | Kai-Hung Huang, 黃凱鴻 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 The number of piglets weaned per sow per year, is considered as the most important indicator in evaluating the productive efficacy of commercial swine herds. The number, however, is mainly influenced by the litter size and pre-weaning mortality. Abortion and stillbirth as well as pre-weaning mortality are among the most important causes of losses in commercial swine herds. Diagnosis of the cause of abortion in swine is seldom straightforward and is frequently unsuccessful. There are two major classes of causes involved in the abortion. The first class are the agents that cause primary infection of the reproductive tract that are probably responsible for 30~40% of abortions, mummies, and stillbirth. The second class, including toxins, environmental and nutritional stresses, and systemic diseases in the sow is responsible for the other 60~70%. This study was a herd-based investigation on the infectious and non-infectious causes of swine abortion and stillbirth. Samples of abortion, stillborns and mummified foetus were collected in two commercial breeding farms in northern Taiwan. Sixty three stillbirths, 26 mummified fetus, 13 middle term abortions and 57 placenta were collected. Stillborn piglets were observed in 25.6% of the litters and the stillborn rate was 4.7% in herd A. Stillborn piglets were observed in 43% of the litters and the stillborn rate was 6.3% in herd B. Nine reproductive pathogens including porcine parvovirus (PPV), porcine circovirus 2 (PCV2), pseudorabies virus (PRV), porcine respiratory and reproductive syndrome virus (PRRS), Japanese encephalitis virus (JEV), classical swine fever virus (CSFV), Brucella suis, Leptospira sp., and Toxoplasma gondii were examined by real-time PCR in this study. The molecular screeing results showed that the positive rate for JEV was 1.2% (2/159)、PCV2 was 50.3% (80/159)、PPV was 11.9% (19/159)、B. suis was 1.9% (3/159) and T. gondii were 3.8% (6/159), and the detection of other pathogens was negative. In the samples examined, the rate of single pathogen infection was 48.4 % (77/159); two pathogens co-infection was 9.4 % (15/159); three pathogens co-infection was 0.6% (1/159)；and 41.5 % (66/159) was negative for all 9 pathogens screened. In total, the delivery information of 323 sows from two pig herds was included in the study. The non-infectious risk factors analyzed included breed, parity, litter size, duration of parturition, body condition score, vaginal palpation during parturition, mummified foetus in the litter and the use of oxytoxin. The results showed that the risk factors well as: Duroc breed sow with litter size more than 12, the duration of parturition more than 3 hours and vaginal palpation during parturition were statistically significantly associated with stillbirth (p< 0.05). Generally, fetal losses (mummified fetuses and stillborns) can vary from about 5 to 15%; stillbirth rate was 5-8 %, mummified rate was 3-5%. Based on these results, appropriate recommendations for improving the performance of sows in each herd would be provided. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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