Metabolic and endocrine profile of crossbred pre-ruminant calves under extended colostrum feeding
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Date
2003
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Department of Physiology, College of Veterinary and Animal Sciences, Mannuthy
Abstract
Colostrum is a highly fortified source of nutrients having seven times
proteins, twice the total solids, higher content of vitamins, minerals and a very
high immune value than normal milk. In most of the commercial dairy farms
where day old weaning of calves is practiced, lion share of this potent calf
protein supplement is practically wasted since colostrum is unmarketable for
human consumption. In this circumstance, the present study was undertaken
with the objective of evaluating the effects of enhanced feeding of preserved
colostrum in neonatal cross-bred calves on the health status, growth,
haematological, biochemical and hormonal parameters and to find any
correlations exist among these factors during their first month of life.
Fresh colostrum was collected in hygienic conditions from recently
calved healthy cows from the first six milkings and then pooled. The pooled
colostrum was preserved in dry sterile bottles by deep freezing at -20°C until
fed to calves. Crude protein content of colostrum and whole milk were
estimated. Total. viable count of pooled colostrum samples were recorded
before and after ultra violet irradiation for 30 minutes. Twelve numbers of
healthy neonatal crossbred calves of either sex of the Kerala Agricultural
University Livestock Farm, College of Veterinary and Animal Sciences,
Mannuthy were divided into two groups as Group I (control) and Group II
(experimental) with six calves in each group. The calves of group I were fed
with colostrum for three days and then milk (one-tenth of body weight) as
followed in the farm. The calves of group 11 were fed with colostrum for 30
days of age continuously at the rate of one-tenth of body weight. All calves
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were provided with drinking water ad libitum and calf starter (250 g/day/calf)
from 15 days of age. The animals were maintained under standard management
conditions.
Regular monitoring of clinical health status and individual weighing at
weekly intervals from day zero (on the day of birth) to one month of all the
calves were performed and recorded. Blood samples were collected from the
calves of both groups soon after birth (zero day), thereafter 18 h after birth (first
day), sixth day, twelfth day, eighteenth day, twenty fourth day and thirtieth day
of age. The blood samples were analysed for blood glucose level and
haematological parameters like haemoglobin content, total erythrocyte, total
leukocyte count, volume of packed red blood cells (VPRC) and subsequently
the erythrocyte indices were calculated. Estimation of concentration of serum
total protein, albumin, globulin, total lipids, cholesterol, triglycerides, non-
esterified fatty acids (NEF A), urea nitrogen (BUN), creatinine and bilirubin
were conducted. Hormonal profile of serum thyroxine (T4), triiodothyronine
(T3) and insulin were estimated.
Clinical parameters of both the groups of calves were within the normal
range. Calves of group II recorded a higher weekly body weight gain. Of the
various haemotological parameters evaluated, haemoglobin concentration and
volume of packed red blood cells exhibited a declining trend, probably due to
the haemodilution after intake of colostrum and milk. The total erythrocyte
count remained almost constant whereas WBe count showed a persistently
an ascending pattern in both the groups,
increasing trend in calves of both
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protein and globulin also exhibited
groups. Serum concentrations of total
which can be attributed to the enhanced absorption' of unaltered
immunoglobulins by pinocytosis, the property which is lost soon after the
maturation of intestinal epithelial cells. Although serum albumin showed a
reduction in concentration after first colostrum intake, due to the increased
absorption of unaltered immunoglobulins from colostrum, albumin
concentration showed a steady rise thereafter till the end of the experiment
indicating the enhanced hepatic albumin synthesis. The electrophoretic
separation of serum protein components of both groups of calves agreed closely
with the biochemical estimation. A steady progressive increase was observed in
serum concentrations of total lipids, cholesterol and triglycerides of calves of
both the groups throughout the experimental period with the magnitude being
more in case of experimental group. This might be explained by the increased
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fat content of colostrum, obviously due to an increased requirement of these
components as membrane constituents and as energy reserves for the build up
of body size and weight. Elevated insulin release stimulated by increased
availability of amino acids would have favoured an increase in triglyceride
synthesis. Fluctuating pattern in serum EF A status of both the groups might
signify reduced mobilisation of fat reserves for energy demands after birth:
Blood glucose level of calves of both the groups followed a continuous
upstream trend, attributed to the increased energy demand for the enhanced
growth. A progressive increment In BUN was more evident In experimental
calves. This could be due to the higher protein degradation and subsequent
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amino acid deamination, probably as a consequence of the high intake of crude
protein and amino acids that were not utilised for protein. synthesis. The
decreasing trend of serum creatinine levels in both the groups could be due to
the decreased glomerular filtration rate (GFR) of serum creatinine at birth
leading to a high serum level at birth, which was reduced later due to the
elevated GFR of creatinine during the early days of life. Increased serum
bilirubin soon after birth could probably be due to the increased destruction of
foetal haemoglobin (Hb) for the replacement of adult haemoglobin after birth.
The serum bilirubin levels diminished towards the last quarter of the
experiment tenure. Serum thyroid hormones eT3 and T4) were not found to be
influenced by time or amount or colostrum or milk fed to calves. There was a
fluctuating trend of T3 and T4 ratios in both the groups. The increase in insulin
concentration after birth in both the groups of calves could be a consequence of
enhanced insulin secretion as a result of greater nutritional intake in the
neonatal life.
The present investigation proved that increased dietary protein In
neonatal cross-bred calves which were fed colostrum continuously for 30 days
from birth brought about elevated protein anabolism in association with
haematological, biochemical and hormonal changes. They were definitely
having an advantage over calves fed colostrum for three days and then switched
to milk as per standard feeding regime. Postnatal growth of ruminants is chiefly
influenced by metabolic hormones, the secretion of which being regulated by
the circulating levels of critical amino acids. The observations of the present
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study revealed that nourishing the neonatal calves with protein rich colostrum
for a prolonged period ensured increased availability of amino acids, especially
the critical ones which can be exploited in enhancing the growth rate of the
calves. Since, there is always an interest in maximising the utilisation of protein
supplements, the most expensive ingredient in ruminant ration, enhanced
feeding of preserved colostrum can be a promising method of improving the
weight gain and health status of neonatal calves in farm conditions. Excess of
colostrum that is usually wasted in large dairy farms, could be properly
preserved and fed to the calves as protein rich nutrient.
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