INGESTIVE BEHAVIOR OF F1 HOLSTEIN X ZEBU COWS FED DIETS CONTAINING DIFFERENT SOURCES OF NITROGEN COMPOUNDS

We evaluated the feeding behavior of F1 Holstein x Zebu lactating cows at 80 ± 12 days of lactation and average production of 20 ± 0.42 kg of milk / day, fed different sources of nitrogen compounds: soybean meal, sunflower meal, detoxified castor meal, and urea. We used two 4 x 4 Latin squares, consisting of four animals, four diets, and four experimental periods. The feeding behavior was obtained by visual evaluation to set the time spent eating, ruminating, idling and to assess ruminating chews and chewing time for ruminal boluses. There was no difference regarding the times spent in feeding (P = 0.1384), rumination (0.5964), idleness (P = 0.6314), number of periods in feeding (P = 0.5995), rumination (P = 0.4575), and idleness (P = 0.4251), duration of periods in feeding (P = 0.2711), rumination (P = 0.8699) and idling (P = 0.4025), depending on the used diet. There was no difference in milk production (P = 0.2755) of the cows among the experimental diets. The addition of sunflower meal to the diet, regarding the use of urea, results in lower consumption of NDF in minutes / kg (P = 0.0399) and, thus, a lesser feed efficiency of dry matter (P = 0.0069). Therefore, some feeding behavior characteristics of F1 Holstein x Zebu lactating cows can be changed by using different nitrogen sources; however, without harming the average production of 20 kg of milk corrected to 3.5% fat / day. Keywords: feeding; fiber; milk yield; protein sources; rumination