This study presents a first approach to determine a suckling bout criterion interval (BCI) by applying a log e frequency analysis to a dataset of Tursiops truncatus neonate feeding frequencies. The data were gathered by continuous observation on four calves 15-24 hr a day for the first 14 days postpartum. The study was conducted at the dolphinarium of the Kolma˚rden Wild Animal Park, Kolma˚rden, Sweden. Based on a total of 3,752 individual suckling intervals, a BCI of 107.7 sec was established. The relevance of this finding is discussed.
The principles of today's machine milking techniques have
developed since the
early 1900s. The original intention to imitate the sucking action of the
calf had to be
abandoned owing to technical difficulties. Further developments were made
on a
largely empirical basis and milking technique became a specific complex
of tasks,
problems and solutions. Consequently, the sucking of the calf was rejected
as a model
for machine milking. The sucking behaviour and the application of vacuum
and/or
pressure by the sucking mammalian offspring have been adapted through evolution.
Any eventual changes due to ‘recent’ breeding and development
of the milking
machine remain marginal compared with evolutionary changes.Since the cineradiographic techniques used by Ardran et al. (1957, 1958)
it was
believed that sucking calves use mainly pressure to transfer a squirt of
milk from the
proximally closed teat cistern and through the teat canal. The calf creates
the
pressure by compressing the teat between the tongue and the hard palate
from the
base of the teat towards the teat end. Cowie (1977) summarized these results
as
follows: ‘Sucking, that is the production of vacuum within the mouth
cavity, is not
an essential feature in suckling, although it aids the process. …
The act of suckling
is thus analogous to hand milking …’. These conclusions were
based on visually
analysed recordings. McDonald & Witzel (1966) measured pressure in
teat cisterns
and vacuum at the teat end simultaneously during suckling. Average maximum
pressure in the teat cistern was 36·6 kPa and vacuum at the end
of the teat averaged
−34·6 kPa. These authors concluded that the average differential
pressure across the
teat canal was 71 kPa. However, this method of calculation gives only the
maximal
pressure difference and not the average pressure applied by the calf. They
noted that
vacuum in the teat cistern occurred during the resting phase of a suckling
cycle. The
calf's sucking technique for single teats during a meal has been analysed
(Mayntz,
1996). Further details of pressure and/or vacuum application during
suckling at a
specific teat remain unknown.The objective of the present study was to extend the current knowledge
about
milk extraction by sucking calves through continuous and simultaneous
measurements of positive and negative pressure in the teat cistern and
in the mouth
cavity.
Abstract. The influence of milk withdrawal, stable routines and separation from dam on suckling behaviour of beef calves was tested in an 8x8 Latin square experiment. Length of the meal and length of the longest bout were measured to describe the meal as a whole. Length of pre-stimulation, increasing ejection, declining ejection, and afterstimulation were measured to describe the structure of meal. Eagerness of suckling was described as relative suckling time and non-suckling. Milk withdrawal increased length of meal and longest bout, but did not influence structure of meal. Milk withdrawal resulted in cistern-milk being available already before ejection and thereby in longer bouts during pre-stimulation. Milk withdrawal had no influence on eagerness of suckling. Stable routines had no influence on meal as a whole, but increased pre- and decreased after-stimulation and tended to result in somewhat longer bouts during pre-stimulation. There was no influence of stable routines on eagerness of suckling. Separation from dam had no influence on meal as a whole or structure of meal, but increased eagerness of suckling for the whole meal and for almost all periods. The experimental results partially sustained results from a field study.
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