Document Type : Research Paper
Authors
1 Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Iran
2 Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
Abstract
Keywords
Main Subjects
Extended Abstract
Introduction
Foot and mouth disease (FMD) is one of the most important infectious diseases in the animal husbandry industry throughout the world. Recognizing the FMD and implementing preventive programs is one of the effective ways to control it. In Iran, the prevalence of FMD is higher in the cold months of the year, especially winter, but due to its endemic nature, it may also be observed in the hot seasons of the year. Serotypes and strains circulating in Iran include A, O, Asia1, AOIR and Opan. The prevalence rate in adult animals is reported to be between 2.5 - 44.2% and the mortality rate varies from 9.1 to 56.4%. In the young animals, the prevalence and mortality rates are estimated between 16.1 – 59.1% and 6.2 - 80%, respectively. The amount of weight loss in calves is about 3%, but in adult cows it is more than 7%. In the cases of FMD, the rate of abortion increased by 60%, and dystocia increased by 11% in affected animals.
Materials and Methods
The data from 9 dairy farms were used between 2009 and 2019. This information included parity, date and type of calving, body condition score (BCS) as well as treatment and cull. The criteria for selecting the studied farms was the size and recording of accurate data related to the disease, and herds with more than 300 cows were included in the analysis. Records were edited by SQL Server 2012 software. The incidence of the disease was calculated based on the data recorded in the treatment file of farms. In order to edit the data, cows without lactation and the number of inoculations more than 10 were removed. In the final analysis, the effect of parity was divided into two levels and the BCS was divided into three categories. To estimate the rate of abortion and stillbirth due to FMD, records were limited to animals with complete health, production and reproduction information including calving date and treatment date. Ultimately, the data set included 49,400 records from 20,330 cows were analyzed. The frequency of FMD at the level of the investigated factors was calculated using the FREQ procedure in SAS software, while the LOGISTIC procedure based on the Chi-Square test was used to study the factors affecting the occurrence of FMD.
Results
The average incidence of FMD and associated cull rate were 43 and 11%, respectively, while they vary between 18-59% and 1-18% across studied farms. Compared to healthy cows, affected cows showed an average 23% decrease in BCS, 5% increase in abortion and 4% increase in stillbirths. The chance of abortion, stillbirth and weight loss in cows that were multiparous and were in the group of normal and fat BCS was lower than primiparous cows with a similar BCS, and on the contrary. The chance of weight loss in multiparous cows, which were in the skinny BCS, was higher than those of primiparous cows with the same BCS group.
Conclusion
In the cold seasons of the year, animals with skinny BCS that have had an abortion during their first calving increase the chance of getting involved in the disease and spreading it in the herd, therefore, vaccination programs on this group of animals can be helpful in disease prevention.
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