Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias

16 t h International Congress on Animal Reproduction
Poster Abstracts 29
hyperimmune serum were produced against Arcanobacterium
pyogenes and E. coli that were isolated in Iranian dairy farms. Cows
in group oxytetracycline (n=39) were treated with one intrauterine
infusion of 5gr oxytetracycline (10%). Cows that did not show any
clinical signs of postpartum endometritis were regarded as healthy
control group (HC, n =91). In group hyperimmunue serum and
oxytetracycline (OTC), all cows were re-examined 39–49 DIM. In
group hyperimmunue serum and OTC, cows were re-treated with
hyperimmunue serum if signs of endometritis were found. Cure rate
after the first treatment, defined as the absence of vaginal discharge at
the re-examinations, was 64.3 % and 61.5% in groups hyperimmunue
Serum and OTC (P > 0.05). Reproductive performance measures
showed no significant differences (P > 0.05) between the two
treatment groups. There was no significant difference (P > 0.05)
Service rate between treatments groups hyperimmunue Serum and
OTC, compared to HC. Conception rates to all services and
percentages of cows pregnant by 180 DIM were 90.48, 86.49 and
92.13 in groups hyperimmunue Serum, OTC and HC, respectively (P
> 0.05). In both treatment groups, cure rate and reproductive
performance measures were better for cows categorized E1 or E2,
than for cows categorized E3 but the differences were not significant.
Conception rate to all services for cows with endometritis (category
E1, E2 and E3) was 52.94 in group hyperimmunue Serum and 57.14
in group OTC compared 66.67 in HC (P > 0.05). The results of this
field trial suggest that hyperimmunue serum could be the alternative
no antibiotic treatment of choice for postpartum endometritis in dairy
cattle.
P005
GnRH-induced LH and ovulatory responses in dairy
heifers during diestrus and proestrus
Ambrose, DJ 1 *, Colazo, MG 1 , Bhuwanee, A 2 , Kumpula, B 2 , Lamont, AL 2 ,
Salmon, F 2 , Suddaby, P 2 , Terletski, S 2
1Agriculture Research Division, Alberta Agriculture and Food, Canada;
2Agricultural Food and Nutritional Science, University of Alberta, Canada
The objective was to determine whether pituitary LH response to
GnRH in Holstein heifers differed between diestrous and proestrous
stages of the estrous cycle. Fifteen postpuberal heifers (13 to 14 mo of
age, 404 to 479 kg body weight) were given 25 mg of dinoprost
tromethamine (PGF; Lutalyse, Pfizer Animal Health) im. Estrus
detection was done twice daily for 4 d after PGF treatment and
ovulation (Day 0) confirmed by ultrasonography. On Day (Mean ±
SE) 8.5 ± 0.6 after ovulation, 100 µg of gonadorelin acetate (GnRH;
Fertiline, Vetoquinol Canada Inc.) was given im to all heifers
(Diestrous stage treatment). Blood samples (n=15/heifer; from 15 min
before to 8 h after GnRH) were collected and plasma analyzed for LH
concentration. One blood sample taken prior to GnRH was analyzed
for progesterone. Ovulation was determined by ultrasonography 48 h
following GnRH treatment and heifers received an intravaginal
progesterone (P4; 1.9 g) insert (CIDR; Pfizer Animal Health) for 7 d,
with PGF administered at CIDR removal. Twenty-four h after CIDR
removal (Day 15.9 ± 0.6), GnRH was given im (Proestrous stage
treatment). Ovulatory response, P4 and LH concentrations were
determined as in Diestrus. Data were analyzed by Proc MIXED,
ANOVA, and Chi-square. Two heifers did not respond to PGF
treatment; both were excluded from the study. Plasma P4
concentration (ng/mL) at GnRH treatment was higher (P < 0.01) in
heifers treated during diestrus (5.7 ± 0.7) than during proestrus (1.0 ±
0.2). The ovulatory response to GnRH treatment was higher during
proestrus than diestrus (P < 0.02; 61.5 vs 15.4%). GnRH-induced LH
peak was lower (P < 0.04; 5.7 ± 0.8 vs 13.6 ± 3.0 ng/mL) and of
shorter duration (P < 0.01; 5.4 ± 0.3 vs 6.8 ± 0.3 h) in heifers treated
during diestrus than during proestrus. Regardless of the stage of the
estrous cycle at treatment, heifers that ovulated after GnRH had a
significantly longer interval from GnRH treatment to LH peak than
those that did not ovulate (P < 0.01; 1.7 ± 0.1 vs 1.0 ± 0.1 h).
However, in heifers treated with GnRH during proestrus, LH
concentrations did not differ (P = 0.60) between those that ovulated
and those that did not. In conclusion, heifers treated with GnRH
during diestrus had lower peak LH concentrations, delayed attainment
of LH peak, shorter duration of elevated LH concentrations, and lower
ovulatory responses than those treated during proestrus.
P006
The Effect of Adding Cholesterol, Vitamin A, Cod Liver or
Flax Oil Loaded Cyclodextrin on Bull Sperm Cryosurvival
Amorim, EAM 1,2 *, Graham, J 2 , Spizziri, B 2 , Meyers, M 2 , Amorim, LS 1,2 , Torres,
CAA 1
1Department of Animal Science, Federal University of Vicosa, Brazil;
2Department of Biomedical Sciences, Colorado State University, USA
Introduction Damage occurring to spermatozoa during
cryopreservation results in a loss of motile cells and cells that are
functionally normal, compared to fresh sperm samples. Treating bull
sperm with cholesterol-loaded cyclodextrins (CLCs) prior to
cryopreservation results in increased sperm cryosurvival, however,
adding cholesterol to bull sperm membranes alters their ability to
capacitate in vitro. This study compared the effect of adding four
compounds, which should incorporate into and increase membrane
fluidity at low temperatures thereby increasing cryosurvival.
Method Twenty-five ejaculates from four bulls were collected using
artificial vagina and extended with Tris, and then sub-divided into 11
treatments: No additive (negative control); 1.5 mg CLC/120 million
sperm (positive control); and 0.75 mg, 1.5 mg and 3.0 mg/120 million
sperm of cyclodextrin pre-loaded with vitamin A or Cod Liver oil or
Flax oil. Methyl-β-cyclodextrin was preloaded with cholesterol as
described by Purdy and Graham (2004). Spermatozoa were incubated
for 15 min at 22 o C. Then, samples were diluted 1:1 (v:v) in Tris with
20% Egg Yolk (EY) and cooled to 5 o C. After dilution 1:1 (v:v) with
Tris containing 10% EY and 16% glycerol, samples were allowed to
equilibrate for 15 min before packaging into 0.5 ml straws, freezing in
static liquid nitrogen vapor (4.5 cm above the liquid nitrogen) for 20
min and plunging into liquid nitrogen for storage. Straws were thawed
in a water bath at 37ºC for 30 sec and the percentages of total motile
in each sample were determined using a computer-assisted sperm
analysis (Hamilton Thorne Motility Analyser).
Results The percentages of motile total sperm cells were maintained
after thawing for bull sperm treated with CLC (45%) compared to all
other treatments (26-41%; P0.05).
Conclusion Therefore, increasing membrane cholesterol levels by
adding CLCs to bull sperm, prior to freezing, is a simple technology
that improved cell cryosurvival, whereas treatments with
cyclodextrins preloaded with other molecules did not.
Acknowledgments Supported by Colorado State University
Experiment Station and CNPq/Brazil.
P007
Bypass fat supplementation in zebu cows (Bos indicus)
in the early postpartum: an alternative to decrease the
open days period
Mesa, C 1 ; Mahecha, L 2 ; Ruiz, ZT 1 ; Gallo, J 3 ; Angulo, J 1,2 *; Olivera-Angel, M 1
1Grupo de Reproducción - Fisiología y Biotecnología, Facultad de Ciencias
Agrarias, Universidad de Antioquia, Colombia; 2 Grupo Grica, Facultad de
Ciencias Agrarias, Universidad de Antioquia, Colombia; 3 Soluciones
Nutricionales S.A., Medellín, Colombia
Introduction Traditional beef cattle production in tropical South
America is extensive and based primarily on Bos indicus cattle and its
crosses. This productive system involves the permanent contact of the
cow with its calf, feeding with low nutritional value grass and the
highly seasonal supply of forage. These characteristics are the main
causes of postpartum anoestrus and the long calving to conception
period (open days). Nowadays, there are some management strategies
which help to decrease the postpartum anoestrus and the open days.
The use of bypass fat in order to increase the energetic contribution of
the diet, and the restricted suckling practices, are some of them.
However, these practices are usually used in a separated way. The
objective of this study was to evaluate the effect of mixing a temporal