Evaluation of productive and reproductive indices in herd of dairy cattle infected with Leptospira spp

• Grant number: 18/19721-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2019
• End date: December 31, 2019
• Field of knowledge: Agronomical Sciences - Veterinary Medicine
• Principal Investigator: Helio Langoni
• Grantee: Frederico Matheus Ducatti de Gois
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Bovine leptospirosis is a disease of great importance for dairy production, both from the productive point of view, due to the low fertility and reduction in milk production, and from the public health point of view, since it is a zoonosis of high prevalence. Objectives: To evaluate the presence of antibodies against 16 serovars of Leptospira spp of importance to herbivores in a dairy herd during the 9-month period, besides evaluating the productive and reproductive levels of the herd, with emphasis on the impact on production of the property. Method: The study is of the longitudinal observational type. Beef cattle of the Dutch breed, pure origin (P.O.), females, lactating kept in a semi-confinement system and milked three times a day. The property where the data will be collected has approximately 750 dairy cattle, with an average of 400 lactating cows and is located near the municipality of São Pedro / SP. The production system is completely computerized, and will be performed monthly, data collection for further evaluation of the productive and reproductive indexes individual and herd, which supply the property database. The milking system is a carousel type, and rodent control is performed by cats. The serological tests for the formation of both groups and monitoring the dynamics of leptospiral infection will be carried out at the Zoonoses Research Center (NUPEZO), Department of Veterinary Hygiene and Public Health, Faculty of Veterinary Medicine and Animal Science, State University Paulista (UNESP), Campus of Botucatu - SP. For the milk production results, for each month, by calculating the corresponding log. This value will be used to calculate the area on the curve (ASC) for each animal, and the mean and standard deviation will be calculated. The ASCs of milk production will be compared between groups 1 and 2 by Student's t-test. Variables with free distribution (age, interval between deliveries, interval between delivery and conception, number of artificial inseminations and number of lactations) will be compared between the groups by the Mann-Whitney test. Dichotomous variables (embryonic loss, placental retention and first service conceptions) will be compared to one another by Fischer's Exact or Chi-square tests.