Herrera Enrique, Palomares Gabriela, Díaz-Aparicio Efrén
CENID-Microbiología, INIFAP, Cuajimalpa, D.F., México.
Ann N Y Acad Sci. 2008 Dec;1149:296-9. doi: 10.1196/annals.1428.011.
The present work aims to quantify milk production in a bovine dairy herd during a 6-year brucellosis control program in Hidalgo, Mexico, where bovine brucellosis is endemic. This 6-year longitudinal pilot study comprised 74 monthly samplings to determine the incidence of brucellosis and to quantify daily milk production. To determine the monthly incidence of brucellosis, an average of 346 Holstein cows was examined each month with the card and Rivanol tests. These animals had been vaccinated as calves with the normal dose of Brucella abortus RB51 and were revaccinated annually with a reduced dose. Brucellosis is endemic in Mexico, where the control programs include vaccination and diagnosis; nevertheless, it is uncommon to carry out other essential control practices, such as separation and elimination of positive cows. In this herd, the cows positive to the card and rivanol tests were separated in specific units, especially at the moment of delivery. These cows were placed at the end of the line for milking and were eliminated from the herd at the end of their productive cycle. In this dairy herd, cows were milked three times a day and there was a monthly average of 300 cows in production. At the beginning of this study the prevalence of brucellosis was 8.43%; from days 180-330 the incidence was from 0.51% to 0.90%. Between days 360-570, the incidence diminished to 0%; between days 600 to 1140, it increased to 4.46%; and from days 1440 to 2220 the incidence was kept beneath 1%. The average of dairy milk production for each cow per day started with 24 L, increasing in direct proportion to the decrease in the presence of new cases of brucellosis: in the subsequent years, the production increased successively to 25, 27, 28, 29, and 30 L. The daily average per year of milk production in the herd was also quantified: at the beginning of the study it was 7220 L and in subsequent years was 7470, 7710, 8340, 8790, 8970, and 9150 L, respectively. We conclude that a direct relation existed between the application of a program of brucellosis control and the increase in milk production.
本研究旨在量化墨西哥伊达尔戈州一个奶牛场在为期6年的布鲁氏菌病控制项目期间的产奶量，该地区牛布鲁氏菌病呈地方流行。这项为期6年的纵向试点研究包括74次月度采样，以确定布鲁氏菌病的发病率并量化每日产奶量。为了确定布鲁氏菌病的月度发病率，每月平均对346头荷斯坦奶牛进行结核菌素皮内变态反应试验和鲁氏碘液凝集试验检查。这些奶牛在犊牛期已按正常剂量接种了流产布鲁氏菌RB51疫苗，并每年以减量进行再接种。布鲁氏菌病在墨西哥呈地方流行，其控制项目包括疫苗接种和诊断；然而，开展其他重要的控制措施，如隔离和淘汰阳性奶牛并不常见。在这个牛群中，结核菌素皮内变态反应试验和鲁氏碘液凝集试验呈阳性的奶牛被隔离在特定区域，尤其是在分娩时。这些奶牛被安排在挤奶队伍的末尾，并在其生产周期结束时被淘汰出牛群。在这个奶牛场，奶牛每天挤奶3次，每月平均有300头奶牛产奶。在本研究开始时，布鲁氏菌病的患病率为8.43%；在第180 - 330天，发病率为0.51%至0.90%。在第360 - 570天之间，发病率降至0%；在第600至1140天之间，发病率升至4.46%；在第1440至2220天之间，发病率保持在1%以下。每头奶牛每天的平均产奶量最初为24升，与布鲁氏菌病新病例数的减少成正比增加：在随后几年中，产量依次增加到25、27、28、29和30升。该牛群每年的日均产奶量也进行了量化：在研究开始时为7220升，在随后几年分别为74
