Embryonic losses in beef and dairy cattle
Vasconcelos, José Luiz MoraesAono, Fernando Henrique SousaPereira, Marcos Henrique Colombo
Background: The profitability of beef and dairy cattle is related to the herd reproductive efficiency, which can be affected by reproductive disorders caused by infectious diseases. The immunization can be used to reduce reproductive losses by the prevention of infectious diseases. Review: Studies have shown that infectious diseases such as IBR, BVBV and Leptospirosis can cause pregnancy losses in beef and dairy cows and there are few information regarding the use of vaccination against IBR, BVDV and Leptospirosis in relation to the reproductive performance. The aim of this study was to evaluate the effect of the vaccine against IBR/BVDV/Leptospirosis (5.0 mL, i.m., Cattle Master® 4 + L5, Pfizer Animal Health, Lincoln, USA) at the beginnig of the TAI protocol on pregnancy rate and pregnancy losses in beef and lactating dairy cows. Five experiments were performed and all cows were inseminated at fixed time (TAI), in beef cows (n = 6145) the pregnancy check was performed at 30 and 120 days post insemination (Exp. 01, 02, 03) and in dairy cows (n = 1960) at 30 and 71 days post insemination (Exp. 04, 05). The experiment 01 was performed to evaluate the rate of pregnancy losses, without any vaccination schedule, and were evaluated 3464 pregnancies in 20 properties. In experiment 02 and 04 were used cows never vaccinated, randomly assigned to receive or not the vaccine, following vaccination schedule: first dose at the beginning of the TAI protocol; second dose at the time of first diagnosis of gestation (30 days post TAI). In experiment 03 the pre vaccination scheme was used within cows that already have a biannual vaccination for leptospirosis, and cows were randomly assigned to receive or not the vaccine against IBR / BVD / Leptospirosis thirty days before the start of the TAI protocol and the second dose at the beginning of the TAI protocol. In experiment 05 cows that received vaccination against IBR / BVD / Leptospirosis in its annual health program, were randomly assigned to receive a single dose of vaccine against IBR / BVD / Leptospirosis at the beginning of the TAI protocol. Data were analyzed by Logistic Regression in SAS. In experiment 01, were detected farm effect (P < 0.05) (results ranging from 1.45% to 12.16%) and order effect (P < 0.05) (Primiparous: 9.03%; Multiparous: 5.06%) on the rate of pregnancy loss between 30 and 120 days. In Experiment 02, treatment affected (P < 0.01) pregnancy rate at 30 (Control: 53.2% and Vaccinated: 57.4%) and 120 days (Control: 48.3% and Vaccinated: 53.5%). In Experiment 03 was detected a tendency of effect (P < 0.10) of treatment on pregnancy rate at 30 (Control: 52.9%; Vaccinated: 59.7%) and 120 days (Control: 50.0%; Vaccine: 57.7%). In experiment 04, animals that received the vaccine had a higher (P < 0.05) pregnancy rate (44.4% vs. 37.6%) on day 30; higher (P < 0.01) pregnancy rate (41.1% vs. 31.7%) on day 71 and lower (P < 0.01) pregnancy loss (7.4% vs. 15.6%) between 30 and 71 days of gestation than the control group. In experiment 05, vaccination in the TAI protocol did not improve (P=0.8) the pregnancy rate on day 30 (34% vs. 34.7%); on day 71 (P=0.88) (30.6% vs. 30.1%) and in the pregnancy loss (P=0.19) (13.2% vs. 9.9%) compared with the control group. Conclusion: These data show that the use of Cattle Master® 4 + L5 had a positive impact on pregnancy rate, and in cows that already received Cattle Master® 4 + L5 in their annual.
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