When given only at processing, an intranasal IB R-P13 vaccine may benefit ADG and feed conversion in newly arrived feeder calves, according to researchers at New Mexico State University. But delaying vaccination with a modified live viral vaccine until seven days after arrival offers no advantage, and the modified live vaccine does not negatively affect performance during the first seven days.

In one experiment, calves were given either an intranasal (IN) vaccine, an intramuscular (IM) vaccine or no vaccine (control) at processing. Compared to those given an IM vaccine, calves given the IN vaccine had significantly greater ADG and improved feed conversion.

In another experiment, calves were given either no vaccine at processing and an IM vaccine on day 7, an IN vaccine at processing and an IM vaccine on day 7, an IM vaccine at processing and on day 7, or no vaccines at all (control). For the overall 28-day period, vaccinated calves had improved feed conversion compared to controls. From days 15 to 28, feed conversion improved for calves vaccinated at processing vs. delayed vaccination.

The percent morbidity did not differ among treatments in either experiment.

For more information contact Glenn Duff at 505/374-2566 or e-mail gduff@nmsu.edu.