THE INTRA-VAGINAL ADMINISTRATION OF LACTIC ACID BACTERIA (LAB) DOES NOT PRODUCE ADVERSE EFFECTS IN BEEF HEIFERS SYNCHRONIZED WITH PROGESTERONE-RELEASING DEVICES

GONZALEZ MORENO, C; OTERO, MC; NADER-MACÍAS, ME

CÓRDOBA

Simposio; Simposio Internacional de Reproducción Animal, IRAC 2013; 2013

Instituto de Reproducción Animal Córdoba

Lactic Acid Bacteria (LAB) are one of the cultivable microbial groups of the vaginal microbioma of healthy heifers, increasing their numbers during the estrous period. Our research group has described previously the predominant LAB species of healthy heifers and cows, selecting those with antimicrobial activity against bovine pathogens (Escherichia coli, Staphylococcus aureus, Actinomycespyogenes) and showing adherence to vaginal epithelial cells. LAB has been successfully applied to prevent the inflammation and infection of the female tract. They are safe microorganisms able to improve the disturbances of the indigenous microbiota, ameliorate the effects of harmful microorganisms, with anti-inflammatory effect (prevent vaginitis) and stimulating the innate host immune response. The progesterone-releasing intravaginal devices (PRID) are frequently applied to synchronize estrusand to increase the reproductive performance in dairy cows, being highly effective also in beef heifers and cows. However, vaginal discharge (VD) in the synchronized cows with PRID has been described by several authors. This vaginal inflammation was associated with a higher risk of anestrous, lower first service conception rate and lower pregnancy rate. The aim of this work was to evaluate the effect of the intravaginal administration of selected LAB (Lactobacillus sp.) in synchronized heifers, with special emphasis in the evaluation ofadverse effects. To this purpose, 20 months old heifers (beef cattle) were enrolled (n= 13) and randomly assigned into 2 groups: control (C n=5) and treated (T n=8). All the heifers were synchronized with PRID and i.m. D+cloprostenol (150 µg)and Estradiol Benzoate (1mg) on day 0. PRID was removed on day 8 and D+cloprostenol(150 µg) and Estradiol Cipionate (1mg) were administered i.m. on the same day. LAB (viable cells suspension) or saline solution (placebo) was administeredintravaginally on days 11, 14, 18 and 21 to T and C animals respectively. Vaginal examination (vaginoscopy), blood collection (by coccygeal venipuncture for hematological profile) and vaginal samples (with cytobrush and cotton swabs, for cytological and microbiological assays) were performed on days 0, 11, 18 and 26. The complete leukocyte count showed normal values in both groups throughout the study. However, a higher percentage of lymphocytes was obtained in T and C animals, probably caused by the stress inducedwiththe sampling methods. No significant differences were detected in the number of cultivable microaerophilic bacteria (Blood agar, 37°C, 5%CO2) between T and C groups. However, a lower number in McConkey agar (for Enterobacteria) was obtained on days 18 and 26 in T group. The number of bacteria grown in MRS agar (for Lactic Acid Bacteria) was higher in C than in T animals.No differences were observed in MSA (for Staphylococcus) between both groups. The VD score (assigned on a 4 point scale, 0= no mucus/ + clear, fluid mucus, 1= ++/+++clear, fluid mucus, 2= yellowish white fluid, 3= white and dense mucus) was lower in the T(6/8)than inC group (0/4)on day 18.The vaginal cytological profile assessed by microscopic evaluation of slides stained (with Papanicolau and May-Grunwald-Giemsa techniques) and a Vaginitis score (high number of vaginal cells, flap and PMN≥10%) were carried out.All the animals showed clinical vaginitis on day 11, probably by the PRID. Control animals exhibited vaginitis signson all the sampling days. However, on day 26, the observed cases with vaginitis were lower in the T group than the expected number (Chi-squared test). The obtained results indicate that the intravaginal administration of LAB did not produce side or adverse effects in synchronized heifers.