科研之友
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摘要
the aim of this study was to determine the variability of natural infestation by amblyomma cajennense and boophilus microplus amongst the tropical milking criollo (tmc) cattle of different age categories and physiological conditions and between periods of sampling carried out during the rainy season in the central area of veracruz, m谷xico. eight categories of bovines were defined: lactating cows of 1-3 births (lc13) and 4-6 births (lc46); dry cows of 1-3 births (dc13), 4-6 births (dc46) and of 7 or more births (dc7), heifers (hf), young bulls (yb) and calves (ca). during eight samples of 21-day intervals, the total amount of saturated ticks (%26gt;4.5mm) on the left side of the body was established in 148 tmc bovines of 215㊣6 to 5694㊣257 days of age. observations were analyzed using a generalized linear mixed model with effects of animal category, sampling period and their interaction, assuming a poisson distribution and a covariance structure in compound symmetry. the effect of period was analyzed as a repeated measure. the main effects (p%26lt;0.05) and interaction (p%26lt;0.01) were significant. lactating cows had the largest infestations throughout the sampling, except in may, in the june1 sampling and in september. by category, uc46 recorded the highest infestation (18.7㊣0.9), followed by uc13 (10.9㊣0.6) and vs7 (6.5㊣1.3). there were intermediate infestations in dc46 (5.3㊣0.7), dc13 (4.3㊣0.6), hf (3.5㊣0.4) and yb (3.2㊣0.6), while ca hay the lowest infestation (2.6㊣0.5). the greatest infestations were shown in october (12.0㊣0.6) and august2 (11.1㊣0.6). there was a correlation between the average number of ticks per individual and average rainfall in a maximum of 21 days before sampling (r=0.83; p%26lt;0.01).
