Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias

16 t h International Congress on Animal Reproduction
10 Workshop Abstracts
ultrasonography has started to become more common in animal
reproduction. This is an emerging technology that has the potential to
increase the diagnostic, monitoring, and predictive capabilities of
theriogenologists and research scientists. Transrectal color-, power-,
and spectral-Doppler ultrasonography have been used in our
laboratory to study ovarian and uterine blood flow and perfusion in
mares. The technology is based on Doppler-shift frequencies, wherein
the ultrasound frequency of the echoes from the moving red cells is
increased or decreased as the cells move toward or away from the
transducer, respectively. Color-flow Doppler ultrasound superimposes
color signals of blood flow on the B-mode (gray-scale) image so that
blood-flow velocities and perfusion can be assessed visually on an
image plane. Blood perfusion to an organ or structure can be
evaluated by scoring the percentage of blood flow (color spots) or by
counting the number of color pixels. Using the spectral mode,
evaluations of blood flow velocities and indices in an artery, which
include peak systolic velocity (PSV), end diastolic velocity (EDV),
time-averaged maximum velocity (TAMV), resistance index (RI), and
pulsatility index (PI), are computed and displayed for a selected
cardiac cycle. Recently, our laboratory has used Doppler
ultrasonography to test several biological hypotheses. These include
the mechanisms involved in follicle deviation, preovulatory follicle
growth, and ovulation; oocyte maturity and competence; embryouterine
dynamics; corpus luteum development, luteolysis, and PGFM
pulses; uterine cyst formation; and the effect of aging on preovulatory
follicle and uterus blood perfusion. Although some limitations have to
be considered, we have found this technology useful for our studies in
reproductive physiology. This presentation will focus on the main
findings of our experiments in mares that used Doppler
ultrasonography to study the relationship between blood flow and
perfusion to the reproductive organs and reproductive processes.
Workshop 05 - Sustainable development in care of
reproduction in small ruminants: efforts and perspectives
Moderator: Dominique Blache (Australia)
WS05-1
Maximising survival of lambs: recent advances through
mother-young bonding
Nowak, R 1 *, Bickell, SL 1 , Poindron, P 2 , Chadwick, A 1 and Blache, D 1,2
1UMR 6175 Physiologie de la Reproduction et des Comportements INRA-
CNRS-Université de Tours-Haras Nationaux, Nouzilly, France ; 2 School of
Animal Biology, The University of Western Australia, Crawley, WA.
In the reproductive process of ewes reared under extensive conditions
there are several points where lamb output can be increased, amongst
which the most important is twinning rate and lamb survival.
However, improvement in twinning rate is seen as unethical if
management systems are inadequate for maximizing the survival of
twin lambs. Despite four decades of worldwide research, lamb
mortality has not improved and recent data confirms that mortality is
still higher in twin than in single lambs. Both genetic and
environmental factors contribute to neonatal mortality. There are 3
opportunities for increasing lamb survival. The first involves breeding
of ewes that provide high levels of maternal care – this is effective but
direct measurements of maternal behaviour are impossible for largescale
operations. A better alternative is genetic selection for ‘calm’
temperament, for which practical on-farm tests are currently being
evaluated across Australia. The second opportunity for reducing lamb
mortality involves improvement of colostrum production. Feeding
supplements to twin-bearing ewes during the last week of pregnancy
almost double the amount of colostrum available at birth. In addition,
the colostrum that is produced by these ewes is less viscous and seems
to be easier for the lamb to suck. Boosting the colostrum intake by
newborn lambs is of particular interest because colostrum is essential
for providing nutrients, for conferring immunity to disease, and for
shaping the early ewe-lamb bond. Successful sucking at birth
facilitates attachment to the mother through a combination of the
rewarding effect of colostrum intake and a neurophysiological effect
of gastric distension. Delays in the provision of colostrum, or the
provision of only small amounts, will thus be detrimental to the ewelamb
relationship. The third opportunity for reducing lamb mortality
involves better management of ewe flocks during lambing. Most
importantly, we need to ensure that shelter, feed and water are nearby,
and that there is a calm lambing environment. This will promote,
rather than disrupt, the formation of the ewe-lamb bond by ensuring
that the mothers do not leave the birth site too soon after parturition
and thus deny sufficient access to the udder for the newborn. Any loss
of mother-young contact early after birth is likely to lead to the death
of twin lambs. Recent research into reproductive physiology and
behaviour has allowed to develop new strategies for increasing twinlamb
survival.
WS05-2
Towards better welfare for small ruminants
Blache, D
UWA Institute of Agriculture M082, University of Western Australia, Crawley
6009, Australia
Farmed animals are exposed to many and varied sources of stress
(stressors) in their life, and those stressors may impact on their
capacity for reproduction. However, to be able to develop strategies
that lead to more sustainable animal care, it is important first to define
and understand ‘stress’ and ‘welfare’.
There is no universal definition for animal welfare and no quantitative
method for measuring it. It is not intrinsic to animals but it is brought
on by the careers as they meet the needs of their animals. The ideal
state, where all needs are provided for, is summarized in the “five
freedoms framework” – freedom from hunger and thirst, from
discomfort, from pain and diseases, from fear and distress, and
freedom to express natural behaviours. Maximum welfare, on a
subjective scale, will be achieved when the animal supervisors do all
they can to prevent or reduce suffering or harm by providing enough
care to fulfill the five freedoms. Generally, the level of animal welfare
is related to the level of stress experienced by the animals. Stress can
be physical, such as inadequate nutrition, fatigue, heat or cold, or it
can be psychological, such as fear of isolation in flocking animals.
Stress can be acute or chronic, and it can be cumulative, and one
stressor can have a potentiating effect for another. Stress is not
necessarily bad for animals and the boundary between ‘good stress’
and ‘bad stress’ is also difficult to define. One useful criterion for
assessing the consequences of stress on welfare is the measurement of
the ability of animals to cope, physiologically and behaviourally, with
challenges.
How do we go towards better welfare for small ruminants As
described above, bad or good stress can be seen as a deviation from
the ‘norm’ and the amount of deviation can be assessed by animal
careers who have a deep knowledge of the biological ‘norms’ of their
animals. This means that animal carers or welfare officers need
education in husbandry, behavior and physiology if we are to assess
and then improve welfare. At the producer level, good stockman skills
are essential because stockmanship assumes respect, understanding
and empathy for animals, as well as dedication to the livestock. A
trained stockman will be able to read the behaviour of the animal and
will know how to handle a particular species. For example, instead of
using fear of noise and pain to make animals move, we can use their
flight zone and flocking behaviour. At the specialist level, training in
stress physiology, regulation of core temperature and behavioural
adaptation to environmental stress, will be necessary for conducting
in-depth welfare assessments. As a complement to these human
changes, selection of animals that are physiologically and
behaviourally better adapted to the farming environment will also
improve their welfare.
Improving animal welfare by reducing stress is obviously beneficial
for the animal but, equally as importantly, it is beneficial for
producers in two ways: i) the quantity and quality of product will
increase; ii) low stress animals are easiest to manage and will lead to
an improvement of the producer’s quality of life and job satisfaction.
Moreover, there is an urgent need for animal production to be ethical
by ensuring that animal welfare reaches the best possible standards –