Banca de DEFESA: LETÍCIA RODRIGUES FARIA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: LETÍCIA RODRIGUES FARIA
DATA: 03/12/2024
HORA: 08:30
LOCAL: Sala
TÍTULO:

Desempenho produtivo e qualidade oocitária de vacas leiteiras alimentadas com farelo de canola em sustituição ao farelo de soja na dieta

PALAVRAS-CHAVES:

 

coproducts, dietary protein, nitrogen, methionine, milk protein.

PÁGINAS: 110
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
SUBÁREA: Produção Animal
RESUMO:

This study aimed to evaluate the effect of isoproteic substitution of soybean meal
with canola meal in the diet of dairy cows. Thirty lactating crossbred Holstein-Gir
cows (11.7 ± 3.2 kg/d milk yield, 168 ± 66 DIM, 493 ± 51 kg BW) were blocked by
genetic composition, parity, and milk yield in a randomized complete block design
study. Cows were randomly distributed to treatments: (1) soybean meal diet (SBM; n
= 15) and (2) canola meal diet (CM; n = 15) for eight weeks. Nineteen cows were
selected for follicular aspiration process in two ovum pick-up (OPU) sessions at 15-d
intervals. Data were analyzed using repeated measures and the model had fixed
effects of treatment (T), week (W), the T × W interaction, and random effects of block
and pen. Model used for oocyte quality, activity of antioxidant enzymes, and plasma
and follicular fluid metabolites in OPU sessions had only the fixed effect of T and the
random effect of cow and OPU session. Milk yield (12.6 vs. 13.5 kg/d) and DMI (15.6
vs. 16.9 kg/d) did not differ (P ≥ 0.21) for cows fed SBM or CM. OM (57.6 vs. 59.8%),
and NDF (44.4 vs. 47.0%) digestibilities were lower (P ≤ 0.02) for cows fed CM than
SBM. Fat content in milk was lower (P = 0.03) for cows fed CM than SBM (4.16 vs.
4.56%). Milk lactose content tended to be greater for cows fed CM than SBM on wk
5 (4.20 vs. 4.04%), but did not differ on wk 3 (4.17 vs. 4.17%) and 7(4.27 vs. 4.19%)
(T × W, P = 0.10). Total solids content tended to be lower (P = 0.06) for cows fed CM
than SBM (12.70 vs. 13.07%). MUN was greater for cows fed SBM diet in wk 5
(17.22 mg/dL), compared to wk 3 (16.04 mg/dL) and 7 (15.99 mg/dL), and lower for
cows fed CM in wk 5 (12.26 mg/dL) compared to wk 3 (13.19 mg/dL) and 7 (13.45
mg/dL) (T × W, P < 0.01). Linear SCC was greater for cows fed SBM diet in wk 5
(4.92) compared to wk 3 (3.78), but did not differ from wk 7 (4.32). For cows fed CM,
linear SCC did not differ between weeks (T × W, P = 0.01). BW was greater (P =
0.01) for cows fed CM than SBM (561 vs. 544 kg). Meal frequency (5.6 vs. 4.6
meals/d) was greater, while the meal duration (69.6 vs. 92.9 min/meal) was shorter
for cows fed CM than for cows fed SBM (P = 0.01). Rumination time of cows fed
SBM in wk 8 (367.0 min/d 1 ) was lower compared to wk 4 (474.0 min/d) and 6 (448.0
min/d); and it was lower for cows fed SBM than CM in week 8 (446.3 min/d, P = 0.02
for T × W). Rumination time while lying down was greater for cows fed CM than SBM
(399.6 vs. 313.3 min/d, P<0.01). The proportion of daily intake in the morning was
greater for cows fed CM than SBM (40.9 vs. 37.7%, P = 0.05). The proportion of
daily DMI at night was lower for cows fed CM in wk 8 (14.5%) compared to wk 4
(24.0%) and 6 (24.5%); and it was lower for cows fed CM than SBM in week 8
(23.7%, P = 0.01 for T × W). Diets did not affect plasma and follicular fluid
metabolites (P ≥ 0.36). N intake, milk protein N, urinary and fecal N excretion (g/d),
the partition on N intake into milk, urine and feces, urinary excretion of allantoin, uric
acid, total purine derivatives, estimated microbial N flow and fecal pH did not differ
between treatments (P ≥ 0.12). Urinary pH was lower for cows fed CM than SBM in
wk 7 (7.3 vs. 7.9), but did not differ in wk 3 (8.1 vs. 8.2) and 5 (8.2 vs. 8.3) (T × W, P
< 0.01). The numbers of total, viable and degenerated oocytes, proportion of viable
and degenerated oocytes, and glutathione peroxidase, catalase and superoxide
dismutase activities did not differ (P ≥ 0.20) between treatments. In conclusion,
utilization of CM in replacement of SBM in isoproteic diets fed to crossbred Holstein-
Gir cows can support similar DMI, milk yield, while decrease milk fat content, MUN,
meal duration and increase BW and rumination time while lying down. Canola meal
diet did not affect plasma and follicular fluid metabolites, as well as N metabolism
and oocyte quality.

MEMBROS DA BANCA:
Externo à Instituição - BRUNO CAMPOS DE CARVALHO - EMBRAPA (Membro)
Interno - ERICK DARLISSON BATISTA (Membro)
Interno - MARCOS NEVES PEREIRA (Membro)
Externo à Instituição - ÁLAN MAIA BORGES - UFMG (Suplente)
Externo ao Programa - RENATO RIBEIRO DE LIMA - DES/ICET (Suplente)
Presidente - NADJA GOMES ALVES (Membro)
Externo ao Programa - MILLER PEREIRA PALHAO - DMV/FZMV (Membro)