Oral and Poster Abstracts

2
University College Dublin, Animal Health and Welfare, Dublin,
Ireland
A total of 46 Irish Holstein-Friesian spring-calving cows were
blocked [lactation number (1 to 8), body condition, body weight,
calving date, predicted milk yield] and allocated to two management
environments [cubicle housing with a total mixed ration pre- and
postpartum (HOUSED) and rotational pasture with grass silage preand
grass and concentrate postpartum (GRASS)]. The occurrence of
reproductive disorders [dystocia, retained foetal membranes and
puerperal metritis, 0-10 days in milk (DIM) and endometritis
(MetricheckTM) 35-49 DIM], the commencement of luteal activity
(CLA) (from thrice weekly milk sampling for progesterone analysis,
EIA) and reproductive performance following a seasonal breeding
period (98 days), were recorded. Proportions were analysed using
Fisher’s exact or chi-square while the collated records for
continuous variables were analysed using Wilcoxon’s or T-test in
SAS, as appropriate. The raw average milk production for the
treatments was of 6,186 kg vs. 7,299 kg for GRASS and HOUSED
cows, respectively. Cows managed in the GRASS environment had a
lower incidence of dystocia (4.4 vs 17.4%, P=0.08), puerperal
metritis (17.4 vs 47.8%, P=0.06), endometritis (9.1 vs 31.8%,
P=0.07) and an earlier CLA (median, and interquintile range: 23, 20-
31 vs 34, 28-50 days, P=0.09). Overall, reproductive performance
was suboptimal and did not differ significantly between groups.
However, it is posited that the lower incidence of uterine disorders
and earlier CLA of the GRASS cows may have contributed to their
numerically higher submission rate (82.6 vs 60.9%, P=0.19), shorter
calving to service (70 vs 75.7 days, P=0.38) and calving to
conception (102 vs 107.1 days, P=0.29) intervals and higher final
pregnancy rate (73.9 vs 60.9%, P=0.53). Though this is a
biologically plausible explanation, limited experimental units may
have reduced the probability of detecting these numerical
differences as statistically significant. It is speculated that treatmentinduced
differences in body condition loss pre- and postpartum and
differential peripartum immune suppression may have contributed to
these findings. In conclusion, cows managed in a GRASS
environment appeared to have an earlier onset of uterine involution
and luteal activity and this appeared to be associated with better
reproductive performance however; the limited scale of this study
precludes robust inference.
Key words: uterine infection, reproductive performance, pasture vs
TMR systems
938 Apoptosis, Placental Maturation and Placental Retention in
Bos Taurus
E. Martins 1 , A. Vasconcelos 1 , A. Marques Jr 2 , J. Ferreira Neto 2 ,
J. Nunes 2 , V. Martins 1 , K. Meça 1
1
Instituto de Ciencias Biológicas UFMG, General Pathology, Belo
Horizonte, Brazil
2
Escola de Veterinária UFMG, Departamento de Clinica e Cirurgia
Veterinaria, Belo Horizonte, Brazil
Apoptosis is an important event for the homeostasis and placental
maturation. A decreased cellularity in placentome close to
parturition suggests that placental release is somehow associated
with that. Here, the role of apoptosis in placental maturation was
evaluated in 42 Holstein puerperal cows, distributed in 3 treatments:
parturition to term (Group I, n= 22); parturition to term and retained
placenta (Group II, n=10) and dexamethasone-induced parturition 5
days before the predicted time (Group III, n=10). Placentomes were
collected and processed. Slides stained by Shorr and MGP were
submitted to morphometry to count caruncular epithelial,
trophoblast binucleated and apoptotic cells. Apoptosis was also
approached by the TUNEL, ELISA (to detect free histones), DNA
electrophoresis (to confirm the internucleosomal fragmentation) and
transmission electron microscopy. Caruncular cells along 100 µm of
epithelium did not differ between groups I (3,59±0,59) and II
(4,28±0,71) (p>0.10). However, group I presented a number of
caruncular cells smaller than group III (4,75 ± 1,56) (p0.01) than
in groups II (4,84±10,84) and III (5,02±11,18). ELISA results were
similar to the morphometric ones, except that groups III and I were
not different (p