TY  - JOUR
T1  - <I>Escherichia coli</I> Vaccine and Laying Hens Mortality After A Heat Stress Challenge in Tropical Climate
AU - Compean, L. Garcia AU - Itza Ortiz, M. AU - Ramirez, A. Reyes AU - Magana-Sevilla, H. AU - de la Rosa, B. Ortiz AU - Zamora-Bustillos, R. AU - Garcia, J.R. Sangines AU - Ugalde, J.P. Ramon 
JO  - Journal of Animal and Veterinary Advances
VL  - 10
IS  - 1
SP  - 96
EP  - 99
PY  - 2011
DA  - 2001/08/19
SN  - 1680-5593
DO  - javaa.2011.96.99
UR  - https://makhillpublications.co/view-article.php?doi=javaa.2011.96.99
KW  - temperature
KW  -mortality
KW  -egg layers
KW  -THI
KW  -E. coli vaccine
KW  -heat stress
AB  - The objective of the present research was to evaluate a vaccine against <I>E. coli</I> in laying hens in tropical climates and its response to heat stress challenge. About 47880 Bovans White laying hens were assigned at two treatments: 24.806 were vaccinated (sprayed) against <I>Escherichia coli</I> and 23 074, the control treatment were not vaccinated. Two applications were made during breeding, the day 1 and week 12. At 16 weeks were transferred form the breeding farm to the layer farm and were distributed at random in a layer house and identified. The daily mortality in both treatments was recorded. A t-test is performed to determine differences between daily mortality rates, differences were found for the three stages: 16-23 weeks (p&lt;0.05) (0.05+0.04 vs 0.08+0.12) from 23-1 to 34 (p&lt;0.0001) (0.04+0.02 vs 0.07+0.03) and 34-1 to 46-2 (p&lt;0.0001) (0.04+0.01 vs. 0.08+0.04). Mortalities in this flock were 14.384% for unvaccinated and 8.224% in vaccinated. Regression analysis were performed for cumulative mortalities before and after a heat stress event, finding that the trend lines have different slopes for birds vaccinated and unvaccinated before and after the event. Vaccination against <I>E. coli</I> showed a lower mortality in the study conditions and a relation whit heat stress event.
ER  -