2011 (SBTE) 25th Annual Meeting Proceedings - International ...

Acta Scientiae Veterinariae, 2011. 39(Suppl 1): Abstracts - 25th Annual Meeting SBTE-Brazil. August 2011.
A077 FTAI, FTET AND AI
EFFECT OF ESTRADIOL BENZOATE AT CIDR INSERTION ON OVARIAN
TRAIT
AITS AFTER SHORT-TERM PROGESTER
OGESTERONE ONE AND
PGF2ALPHA BASED ESTROUS-SYNCHR
OUS-SYNCHRONIZA
ONIZATION PROTOC
OCOL OL IN SHEEP
José Franscisco Cox 1 , Evelyn N Lara 2 , Andrea F Leiva 3 , H Muñoz 4 , Rodrigo V Allende 5 & Fernando R Saravia 6
1,2,3,4,5,6
UNIVERSIDAD DE CONCEPCIÓN, CHILLÁN, CHILE.
Estradiol benzoate (EB) has been used in cattle to control follicular emergence and to potentiate progesterone to accelerate
dominant follicle turnover. The study was aimed to study the effect of EB at CIDR insertion on ovulatory follicular traits and interval to
ovulation during the mid breeding season in sheep in ewes subjected to short-term progesterone protocol for estrous synchronization. Fifty
four ewes under controlled feeding were synchronized by the insertion of intravaginal progesterone-release device (CIDR G, 0.3 g progesterone,
Pfizer) for 6 days combined to cloprostenol (0.125 mg im Estrumate, Intervet) and eCG (400 IU Novormon, Syntex) at CIDR removal (n =
22) or as before plus 0,5 mg EB at CIDR insertion (n = 32). Antral follicular dynamics was followed daily since CIDR retrieval and each 8 h
since 12 h after estrus detection by transrectal ultrasonography using a 10-MHz linear array probe connected to a B-mode scanner (Honda
HS 2010Vet, Japan). Follicles = 2,5 mm and CLs that were recorded by sketches on ovarian charts. The preovulatory follicular diameter was
measured on ovulated follicles that were later confirmed at CL measure 10 days after estrus. To determine ovulation time, ewes were scanned
until ovulation, and the moment of ovulation was defined as the middle point between the last identification of preovulatory follicles and their
disappearance. Therefore the interval between both CIDR retrieval and estrus detection to ovulation were the periods in hours between these
points. Follicular and CL traits and the interval to estrus and ovulation between treatments were compared by the Student’s t-test and a P <
0.05 was considered significant. The results show that both the size of ovulatory follicles and that of CLs at day 10 after estrus were similar
(6.0±0.09 vs.. 6.1±0.13 mm; 11.1 vs.. 10.5 mm in diameter for treated and untreated groups respectively; P > 0.10). However, EB increases
the intervals from the end of treatment to estrus and ovulation (40.3±1.84 vs.. 34.1±1.97 h; 70.1±1.91 vs.. 64.1±1.96 h for treated and
untreated controls respectively; P < 0.05) and reduces the ovulatory response compared to untreated ewes (82.1% vs. 95.7%; 1.26 vs.. 1.82;
for ovulation rate and number of follicles ovulated for treated and untreated ewes respectively; P < 0.05). Cumulative information suggest that
estradiol benzoate added at CIDR insertion has an inhibitory effect on FSH profiles that delays the emergence of antral follicles and reduces
the ovulatory rate and the number of follicles ovulated in treated ewes without other observable changes in follicular development and in CL
development after ovulation. [Funded by Consorcio Ovino (FIA FIC-CS-C-2006-1-P-001-22)].
Keywords: estrous synchronization, estradiol, sheep.
A078 FTAI, FTET AND AI
TAI INCREASES THE REPRODUCTIVE PERFORMANCE OF LACT
CTATING TING PRIMIPAR
AROUS ACY
CYCLIC CLIC NELORE COWS
Rodrigo Ribeiro Cunha 1 , Marilu Martins Gioso 2 , Regis José De Carvalho 3 , Carlos Antônio De Carvalho Fernandes 4 , Miller Pereira Palhão 5 , Marina Resende
Pimenta Portinari 6 & Thais Camargo Rossi 7
1,2,3,4,5,6,7
UNIFENAS, ALFENAS, MG, BRAZIL.
N
The objective of this experiment was to evaluate the efficiency of a Fixed Time Artificial Insemination (TAI) protocol in an
attempt to improve the reproductive performance of primiparous lactating acyclic Nelore cows. The experiment was conducted for a period
of breeding season (BS) of 180 days. Were used 350 Nelore cows with body condition score (BCS) greater than 2.5 (average 2.65 ± 0.01) and
days postpartum average of 67.35 ± 1.0 days. The animals were divided into four groups: G1 (n = 61) and G3 (n = 116) - cows with ovarian
follicles smaller than 8mm in diameter and absence of CL. G2 (n = 57) and G4 (n = 116) - cows with follicles greater than 8mm and absence
of CL. G1 and G2 remained with the bulls in the management of natural mating (NM) throughout the experimental period, from day 0 of BS.
The G3 and G4 were treated (Day 0) with an intravaginal device containing 1.0 g of P4 for 8 days and 2mg (2mL) of estradiol benzoate (EB)
IM. The withdrawal of P4 (Day 8) were applied IM 400 IU (2mL) of eCG and 75µg (2mL) of cloprostenol and 24 h later (Day 9),
administered 1mg (1mL) IM BE. The TAI was performed between 51-54 h after withdrawal of P4 (Day 10) using semen from a single bull.
After five days of the TAI, cows in groups G3 and G4 were submitted with bulls in the management of NM. All animals were evaluated by
ultrasound for cyclicity rates (presence of CL) and pregnancy diagnosis at 35 and 180 days after onset of BS. For the analysis of the presence
of CL and pregnancy rates at 35 and 180 days, between groups, were performed a chi-square. For the variable: period of service was used
ANOVA and Duncan. At 35 days of BS, the G3 (42.24% A) and G4 (51.70%) presented higher rates of pregnancy (P < 0.05) than G1 (0%
B) and G2 (35% B). A greater number of ovulations was also found (P < 0.05) in G3 and G4 when compared to animals maintained only during
NM (6.56% C, 28.07% B 50.86% A, 62, 93%, for G1, G2, G3 and G4, respectively). Pregnancy rates at 180 days were: 22.95% C (G1),
45.61% B (G2), 40.51% B (G3) and 65.51% A (G4). For percentage of animals with CL at 180 days of MS, the G4 (71.55% A) obtained better
results than Groups 1, 2 and 3 (42.62% B 56.14% B 48.27% B, respectively). Additionally, groups of TAI + eCG had shorter periods of
service (days, P < 0.05): G1 (134.00 ± 11.70 A), G2 (119.65 ± 8.27 A), G3 (79, 91 ± 5.38 B) and G4 (81.40 ± 4.59 B). The work suggests
that the TAI was effective to improve the reproductive efficiency of primiparous lactating acyclic Nelore cows in compared to females
subjected only NM. In addition, primiparous cows subjected to TAI at the beginning of BS had the reduced postpartum anoestrus period and
increased pregnancy rates than cows subjected only to NM.
Keywords: ecg, body score condition, zebu breed.
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