Behavior of crossbred cows grazing ‘Mombaça’ grass and forage characteristics in the semiarid region

Abstract

The objective was to evaluate four grazing intensities (10, 25, 40, and 55 cm of residue height) on the yield characteristics of Panicum maximum Jacq. ‘Mombaça’ and feeding behavior of crossbred cows under grazing in the Bahian semiarid. The design used in the experiments was a Completely Randomized Design (CRD), with four treatments (grazing intensity) and five repetitions (paddocks). Five crossbred cows (Holstein x Gir) with an average weight of 500 kg were used as evaluator animals. Pasture evaluations were carried out through simulated grazing every 28 days. Ingestive behavior was assessed by visual observation and the temperature of the corporal surface was measured with a digital thermometer after milking and during the grazing period of the animals. There was a linear increase (P < 0.05) for total dry mass (TDM), leaves dry mass (LDM), forage accumulation rate (FAR), total dry mass supply (TDMS), and leaves dry mass supply (LDMS). The minimum percentage of leaves (P < 0.05) of 82.2% was observed at the residue height of 34.9 cm. It was observed that the Temperature and Humidity Index (ITU) was in attention and alert during the months of evaluation. There was a linear increase (P < 0.05) in the temperature of the corporal surface from 32.2 to 36.4 ºC, over the months of evaluation. For each increase of 5.0 cm in the residue height, an increase (P < 0.05) of 0.146 no/minute and 52.6 no/day is expected in the bit rate, respectively. For the feeding station, a reduction (P < 0.05) of 0.162 nº/minute and 58.2 nº/day is expected, respectively. The dry matter intake (DMI) and average daily gain (ADG) increased linearly (P < 0.05) between grazing intensities. At the grazing intensities of 40 and 55 cm, there was a variation from 3.25 to 3.50 in the body condition score (BCE). Grazing intensity of 45.2 cm (residue height) is recommended, as it allows an adequate forage yield and bites, and less displacement between feeding stations.