Oral and Poster Abstracts

methods; ANOVA (with binary classification of lameness), ANOVA
with a lameness index (LAMIX) as the variable of interest, and
ANCOVA (controlling for mean milk production for the first 3
weeks of lactation and with a binary classification of lameness).
Data were from one dairy farm located near Ithaca, NY, from the
calvings that occurred from 1 January 2004 to 1 January 2007. The
LAMIX was defined as: -1, -2, -3, -4, and -5 = 1, 2, 3, 4, and 5
months before lameness was detected respectively; 1, 2, 3, 4, and 5 =
1, 2, 3, 4, and 5 months after diagnosis respectively; and 0 = cows
that were never lame. With binary lameness classification analyzed
by repeated measures ANOVA, there was no effect of lameness on
milk yield. This model was biased because lame cows had higher
milk yields prior to lameness compared to non-lame cows. When the
lameness index was used, milk production prior to lameness was
greater than after lameness. However, point estimates generated for
lameness index can be inaccurate because of the multicolinearity
detected between lameness index and week of lactation, and also
because of the inability of adjusting the LSM for the interaction of
lameness index and week of lactation. Therefore, we concluded that
the most appropriate models were the ANCOVA models (both for
the matched and non-matched retrospective-cohort designs). The
estimated losses associated with lameness were 314 and 424 kg/cow
305-d lactation, respectively, for the matched and non-matched
designs. Furthermore, high milk yield in the beginning of the
lactation was a risk factor for lameness.
263 Functional Trimming at the Dry – off Period to Prevent Foot
Diseases in Confined Dairy Cows in the Tropical Area
D. Garcia, M. Hahn, D. Pino, I. Vivas, M. Leal, K. Clerc
Universidad Del Zulia, Medico Quirurgico, Maracaibo, Venezuela
The aim of the present research was to evaluate the functional
trimming effect at the dry off period to prevent the hoof diseases in
confined milking cows. To do that 47 Brown Swiss cows with two or
more parturition were study at the beginning of the dry off period.
The cows were divided in two groups in a random way. One group
received the functional trimming as treatment and the other one
serve as a control. The cows were monitor to look into the
appearance of hoof diseases within the first 5 months of the milk
yield period. The results show that 39% of the hoof had any kind of
lesions and 61% of the hoof were without lesions, in the same way
the treated animal group show only 4% of sick animals whereas in
the control group were 45.4%. A comparison study of both groups
show a significant statistically differences (p