ABSTRACT
The objective of this case study was to provide an innovative and practical approach to induce parturition in delayed pregnant dairy cattle. Retained fetal membranes is a common consequence of chemically induced calving, predisposing cows to postpartum uterine diseases such as metritis. In addition, veterinary costs increase following postpartum disorders that may affect reproductive performance of early lactation cows. Therefore, to help optimize cow and calf health and productivity, we recommend that the herein-explained practical-manual-natural approach of rectal palpation be practiced instead of drug administration to induce normal calving in delayed pregnant cows.
Keywords: Delayed Cow; Parturition; Drug; Rectal Palpation; Natural Calving
Method and Discussion
This case study report aimed to provide an innovative and
practical approach to induce parturition in delayed pregnant
dairy cattle. Chemical calving induction is a process in which
parturition is induced by administrating exogenous hormones and
corticosteroids. Having a natural calving, however, is important for
optimal health and future productive and reproductive performance
of dairy cows. In addition, neonatal calf survival and health can be
negatively influenced by any disturbances in the natural calving
process. Dystocia and premature calf birth can lead to calf morbidity
and mortality due to hypoxia and metabolic acidosis. Chemical
induction of parturition was initially performed in beef and sheep
production systems [1]. Likewise, in some parts of Australia and
New Zealand, calving induction is being used in pasture-based
dairy systems with seasonal reproductive programs [2]. These
programs are planned to maximize pasture use as an economical
feed source. However, induced cows have produced 4% lower milk
than those calved normally [2]. Retained fetal membranes is a
common consequence of chemically induced calving, predisposing
cows to postpartum uterine diseases such as metritis. Therefore,
veterinary costs increase following postpartum disorders that may
affect reproductive performance of early lactation cows.
Health problems associated with chemical calving induction
can also affect animal welfare negatively. Because of these issues,
The Australian Veterinary Association (AVA) suggests that the
induction of parturition should be cancelled in dairy herds with
seasonal calving programs. Additionally, the AVA supports gradual
remove of chemical calving induction by 2022. Natural calving
process may be postponed in some dairy cows, causing oversized
calves and dystocia. This is more noticeable in primiparous cows
because they have more difficulty in delivering an oversized calf than do multiparous cows. As a result, heifers can be culled
because of pelvic injuries during dystocia. Moreover, calf loss may
occur during severe dystocia. To avoid these problems, induction
of parturition may be a useful practice. In other cased such as
downer, lamed, and under-conditioned cows that are unable to
calve normally and timely, the induction of calving would be an
appropriate way to reduce the risk of sever dystocia and calf loss.
Intramuscular injection of corticosteroids such as dexamethasone
alone or combined with prostaglandins (PGF2α) are routine ways
to induce calving [3]. In the majority of cases, parturition will
happen 45-75 hours after injection. However, these methods do
possess undesirable health consequences for both calf and dam.
As a herd protocol in our dairy herd (Behroozi dairy complex,
Tehran, Iran), pregnant animals are allowed to naturally calve
between 270-282 d of gestation for healthy calving with no
manipulation and pulling of calf. After the above time period and
if calving has not yet occurred, cows and heifers are monitored via
rectal palpation to check calf survival and probably calf malposition.
If the calf is still alive, one more day is given to allow a natural
calving to occur. In delayed or prolonged calving (i.e., > 283 d of
gestation) in both cows and heifers, induction of parturition will
be necessary. Instead of chemical induction with administration
of dexamethasone and PGF2α analogues that may cause retained
placenta and metritis as well as calf health issues and mortality,
rectal palpation and moderate stimulation is practiced inducing
natural calving. In our experience, natural parturition usually occurs
within one- or two-day of rectal palpation. With this feasible and
natural method of calving induction, delayed cows are able to calve
naturally without any artificial drug administration. It is necessary
to emphasize that during palpation and manual stimulation, calf
is modestly moved inside the uterus to induce initiation of the
parturition process. In our experience, pushing digital part of calf
hooves modestly and gently provide suitable stimuli to help the calf
move. After this, calf delivery would be expected to occur within
24-48 hours.
Rising cortisol levels immediately before calving has a pivotal
role in initiating parturition. Fetal cortisol may be one of the most
important physiological modulators that promote parturition
in cattle [4]. In addition, maternal cortisol arises as a part of
parturition process and stress-like response can be seen during
labor [5]. As such, it seems that parturition induction by rectal
palpation and manual stimulation of the calf can be a result of fetal
cortisol secretion. In other words, we postulate that pushing calf
digits in the uterus could induce some degree of stress to the calf
which promotes cortisol secretion.
Conclusion
Therefore, to help optimize cow and calf health and productivity, we recommend that the above-explained practicalmanual- natural approach be practiced in delayed cows instead of drug administration.
Acknowledgment
Behroozi Dairy Complex’s (Tehran, Iran) management and staff are thankfully acknowledged for their insight and assistance.
References
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