Banca de QUALIFICAÇÃO: ELAINE COIMBRA DE SOUZA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ELAINE COIMBRA DE SOUZA
DATE: 13/12/2023
TIME: 08:00
LOCAL: Universidade Federal de Rondônia
TITLE:

BEHAVIORAL AND THERMOREGULATORY RESPONSES OF HEIFERS NELORE IN INTEGRATION SYSTEMS IN THE STATE OF RONDÔNIA

KEY WORDS:

thermal comfort; beef cattle; iLPF; ILP.

PAGES: 66
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUMMARY:

The objective was to evaluate the thermal comfort of Nelore heifers in Crop-Livestock Integration (iLP) and Forestry (iLPF) systems based on the investigation of animal behavior and physiological parameters. For this purpose, a 2x2 crossover design was used (two periods and two systems), with eight Nelore heifers, with an average body weight of 228±28 kg and an average age of 11±1 months, distributed in the iLP and iLPF systems. The heifers were kept on Brachiaria hybrid cv. BRS Ipyporã and managed in intermittent stocking with 10 days of occupation and 30 days of rest, with the iLPF being shaded by Eucalyptus pellita trees, arranged in seven rows of double rows. Behavioral activities were collected from acoustic data, using MP3 audio recorders, for 24 hours of each period. Simultaneously, the internal temperature (IT, ºC) and respiratory rate of the heifers were measured. Dry matter intake (DMI) was also estimated, based on the relationship between daily fecal production estimated with the external indicator LIPE® and the in vitro digestibility of dry matter (DIVMS) of the diet. Air temperature data with globe thermometers were also collected to calculate the Black Globe Temperature and Humidity Index (ITGU). Statistical analysis was performed using the SAS® Mixed procedure. The averages were compared using the t test and F test at 5% significance. The ITGU presented averages of 81 and 82 (iLPF vs. iLP, respectively) during the day, indicating a dangerous situation for the animals and an average of 74 for both systems at night, indicating thermal comfort. Nelore heifers spent 15.14 and 10.86 minutes more on grazing activity at 08:00 and 11:00, respectively in the iLP system. In the iLPF system, the time spent grazing was 11.79 minutes longer at 11:00 pm compared to the iLP. At 08:00 and 12:00, heifers spent 15.64 and 11.57 minutes, respectively, more in rumination in the iLPF system vs. iLP. While the time spent drinking water was 0.21 minutes longer at 2:00 pm and 11:00 pm, in the iLP system and 0.28 minutes longer at 10:00 am in the iLPF system. The heifers' IT averages were higher in the iLP system when compared to the iLPF system, at 08:00, 11:00, 12:00, 16:00, 21:00, 22:00, 23:00 and 05:00. In relation to the grazing behavior and IT of heifers, it is concluded that despite the differences between the systems in the activities of grazing, rumination and water intake at certain times, the arboreal component does not infer changes in the total time spent on these activities. However, the lowest internal temperature value of heifers is verified in the iLPF system.

COMMITTEE MEMBERS:
Presidente - ***.237.228-** - ANA KARINA DIAS SALMAN - EMBRAPA
Interno - ***.305.370-** - LUIZ FRANCISCO MACHADO PFEIFER - EMBRAPA
Externa à Instituição - FABIANA ALVES DEMEU - IFRO
Externo à Instituição - JOMEL FRANCISCO DOS SANTOS - IFRO
Externo à Instituição - PEDRO GOMES DA CRUZ - EMBRAPA