Banca de DEFESA: WESLEY DE REZENDE SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: WESLEY DE REZENDE SILVA
DATA: 04/08/2025
HORA: 08:00
LOCAL: Online, google meet
TÍTULO:

PERFORMANCE OF LACTATING DAIRY COWS FED AN ALPHA-AMYLASE ENABLED CORN

PALAVRAS-CHAVES:

Enzyme; Enogen; processing; starch; vitreousness

PÁGINAS: 180
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
RESUMO:

The alpha-amylase enabled corn (AAC; Enogen, Syngenta) may be an alternative to improve feed efficiency of lactating dairy cows. Three experiments were conducted to evaluate the effects of the AAC corn on lactation performance, intake, feed efficiency, total tract digestibility, ruminal fermentation profile, N partition, and eating and rumination behaviors of lactating dairy cows. Holstein cows (20 cows in experiment 1; 24 cows in experiment 2; and 22 cows in experiment 3) formed groups based on parity and milk yield and were allocated to one of 4 treatments using a 4 × 4 Latin Square design with 21-d periods (14 d for diet adaptation). Treatments were in a 2 × 2 factorial arrangement of Factor 1) corn concentration [High (28.7% starch, 24.6% corn, 2.5% citrus pulp) vs. Low (21.5% starch, 14.1% corn, 13.8% citrus pulp)] and Factor 2) corn type (AAC vs. Isogenic control - CTL fed as a rehydrate and ensiled corn) in experiment 1; Factor 1) corn processing (rehydrated and ensiled corn vs. ground corn) and Factor 2) corn type (AAC vs. CTL) in experiment 2; and Factor 1) whole plant corn silage type (AAC vs. CTL) and Factor 2) corn kernel processing [Fine (80.1 µm of geometrical mean particle size) vs. Coarse (195.8 µm of geometrical mean particle size) griding] in experiment 3. Vitreousness of corn hybrids was 48.8% for AAC and 51.1% for CTL in experiments 1 and 2, and of 75.8% for AAC and 75.1% for CTL in experiment 3. Rehydrated and ensiled corn used in experiments 1 and 2 were stored for 28 ± 3 d and whole plant corn silage from experiment 3 was stored for 98 ± 42 d before opening. The utilization of AAC fed as a concentrate source can improve neutral detergent fiber (experiment 1) and starch digestibility (experiment 2) and improve feed efficiency in diets with low corn concentration, without affecting milk yield and dry matter intake. Milk composition and chewing behavior were not affected by AAC in experiments 1 and 2. The AAC corn did not affect the ruminal proportion of the major volatile fatty acids and the microbial synthesis in the rumen, but affected the proportion of ruminal branched chain volatile fatty acids in experiment 1 and 3. The N partition was not affected by AAC in experiment 2, but when fed in a diet with high corn concentration (experiment 1) AAC decreased blood and plasma urea-N, and the excretion of N in total excreta (feces + urine). The supplementation of AAC as whole plant corn silage in combination with coarse grinding corn kernels decreased dry matter intake, leading to a decrease in lactation performance in cows fed AAC. There is a possibility of using AAC as rehydrated and ensiled corn to improve lactating dairy cows efficiency, but it seems to be affected by the carbohydrate profile of the diet.

MEMBROS DA BANCA:
Externo à Instituição - RENATA APOCALYPSE NOGUEIRA PEREIRA - EPAMIG (Membro)
Interno - MARINA DE ARRUDA CAMARGO DANES (Membro)
Presidente - MARCOS NEVES PEREIRA (Membro)
Externo à Instituição - JÚLIA DIANE LIMA DIAS - UFLA (Suplente)
Externo à Instituição - JOÃO LUIZ PRATTI DANIEL - UEM (Membro)
Externo à Instituição - GUSTAVO GONÇALVES DE SOUZA SALVATI - ESALQ (Suplente)
Interno - CARLA LUIZA DA SILVA AVILA (Membro)