Banca de QUALIFICAÇÃO: LUIZ MARCOS SIMÕES FILHO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: LUIZ MARCOS SIMÕES FILHO
DATA: 08/07/2021
HORA: 10:00
LOCAL: Remoto
TÍTULO:

Effect of yeast prebiotics on growth performance, milk replacer intake, diseases, and immunity of female Holstein calves

PALAVRAS-CHAVES:

calves, dairy cattle, glucans, haptoglobin, immunity, yeast cell wall

PÁGINAS: 60
GRANDE ÁREA: Ciências Agrárias
ÁREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
RESUMO:

Yeast cell wall prebiotics may affect immunity, performance, and the response of dairy calves to stressors, such as dehorning and weaning. Our objective was toevaluate the effect of two prebiotic blends fromSaccharomyces cerevisiaecell wallon nursing Holstein female calves subjected to dehorning and weaning.The experiment was conducted in a commercial herd (Fazenda São Jorge, São Pedro/SP) from January to March, 2020. Forty-five calves formed 15 blocks by birth sequence and received a treatment until weaning.Treatments were: Control (CTL) or prebiotics1 (PRE1) or 2 (PRE2). Dosages from 2 to 30 days, 31 to 60 days, and 61 to 75 days were, respectively: 3, 6, and 9 g/d of PRE1 and 5, 10, and 15 g/d of PRE2. Milk replacer (120 mL) with or without treatments was orally dosed to each calf daily. Calves were individually housed and feduntil 17.9 ± 2.2days and then were group fed with an automatic milk feeder. The intake of milk replacer, rectal temperature at 0700 h, diseases, and treatment drugs were recorded daily. Body weight (BW) was measured at birth, dehorning, and weaning. Dehorning was at 34.9 ± 3.2 days and weaning at 75.1 ± 2.21 days. Blood serum samples were obtained on days -1, +1, +3, and + 7 relative to the stressors. Significance was declared at P ≤ 0.05 and trends at P ≤ 0.10.There was no calf mortality during the experiment, but 100% of calves in a treatment had at least one event of rectal temperature ≥ 39.5^oC (fever), more than 50% had diarrhea, and more than 30% had pneumonia. Survival analysis suggested that there was not a treatment effect on the first episode of diseases. The PRE1 increased the mean rectal temperature from 2 to 30 days (39.0 vs 38.9^oC) and increased the frequency of days with fever (11.1 vs 7.0%) relative to CTL and PRE2. Prebiotics did not affect the frequency of diseases neither disease treatment cost. From birth to dehorning, there were trends for PRE1 to reduce BW gain relative to PRE2(407 vs499 g/d). There was no treatment effect on BW gain (529 g/d) and milk replacer intake(6.7 L/d) from birth to weaning. There was no treatment effect on blood TNF-ɑ and IL-6 around dehorning and weaning. Around dehorning, there was no treatment effect on haptoglobin. On day -1 relative to dehorning, the IL-1β was higher on PRE1 than PRE2 and there was a trend for PRE1 to be higher than CTL. The PRE1 also tended to increase IL-1β relative to PRE2 on day +7 after dehorning and PRE1 tended to increase IL-4 on day +7 relative to PRE2. On days+1 and +3after weaning, PRE2 tended to reduce haptoglobin relative to PRE1. There were trends for serum IL-1β on day +1 after weaning to be lower on CTL and PRE2 than on PRE1 and on this same day there was a trend for PRE1 to increase IL-4 relative to PRE2. The increase in IL-4 and IL-1β in response to PRE1 suggests that PRE2 was less inflammatory than PRE1. Under this calf management scenario, yeast prebiotics did not affect the incidence of fever, diarrhea, and pneumonia, disease treatment costs, BW gain, and milk replacer intake.

MEMBROS DA BANCA:
Presidente - ALESSANDRO DE SÁ GUIMARÃES - EMBRAPA (Membro)
Interno - ELAINE MARIA SELES DORNELES (Membro)
Externo ao Programa - ERICK DARLISSON BATISTA - DZO/FZMV (Membro)
Externo ao Programa - CARLA LUIZA DA SILVA AVILA - DZO/FZMV (Membro)
Externo à Instituição - RAYANA BRITO DA SILVA - BN (Suplente)