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The Effect of Tasco TM Inclusion in the Prepartum Diet and
Time of Sampling on the Proportions of Bovine Leukocyte Populations in
Blood and Mammary Gland Secretions
T. J. Wistuba, 1 E. B. Kegley, 1 T. K. Bersi, 2 D. W. Kellogg, 1 and G. F. Erf 2
Story in Brief
The effects of Tasco TM inclusion in the diet during the last 21 d of gestation on the proportion of bovine leukocyte
populations in blood and mammary gland secretions (MGS) was investigated using flow cytometric analysis. Thirty
Holstein cows were stratified by parity and randomly assigned to the Tasco TM (170 g/d) supplemented group or control
diet. Tasco TM is a product derived from Ascophyllum nodosum, a brown seaweed that grows along the coast of Nova
Scotia. Treatments were initiated 21 d prior to expected parturition and fed until calving. Blood samples and MGS from
cows and blood samples from calves were obtained at parturition and at d 1 post partum. Proportions of bovine leukocyte
populations in cows were affected by dietary treatment, but not time of sampling. In cows, supplementation of
Tasco TM increased the proportion of B lymphocytes (P = 0.05) in the blood. However, Tasco TM supplementation
decreased the proportion of T-helper lymphocytes (P = 0.04) and tended to decrease the proportion of gd T lymphocytes
(P = 0.13). The percentage of B lymphocytes tended to increase (P = 0.13) from parturition to d 1 in the MGS.
Proportions of granulocytes, macrophages/monocytes and B lymphocytes in the blood of calves increased from parturition
to d 1 (P < 0.04). Dietary supplementation with Tasco TM and time of sampling altered proportions of bovine leukocyte
populations. The impact of Tasco TM supplementation on cow and calf health requires further investigation.
Introduction
Trace mineral or vitamin supplementation has been
shown to improve immune response and growth performance
when animals are consuming deficient or marginal levels of
trace minerals or vitamins. Tasco (Acadian Seaplants Ltd.;
Dartmouth, Canada) is a product derived from Ascophyllum
rodosum, a brown seaweed, that grows along the coast of
Nova Scotia. The commercial product that has been developed
contains high levels of trace minerals and vitamins.
Initial work using Tasco TM at Virginia Tech, Mississippi State
University, and Texas Tech has shown improvements in
immune cell function and hair coat scores of calves grazing
fescue but no significant improvements in growth performance
(Allen et al., 2001; Fike et al., 2001; and Saker et
al., 2001).
It has been well documented (Quigley and Drewry,
1998 and Wittum and Perino, 1995) that the passive transfer
of immunoglobulins in colostrum is the most important
source of immunologic protection available to neonatal
calves. Inadequate intake and absorption of maternal antibody
has been associated with increased risk of disease and
death in neonatal calves (Wittum and Perino, 1995) The concentration
of immunoglobulin G (IgG) in colostrum is important
in determining the degree of passive immune transfer,
being linearly related to the maternal IgG concentration in
calves. The objective of this study was to determine the
effects of Tasco inclusion in the prepartum diet on the proportion
of bovine leukocyte populations and IgG concentrations
in blood and mammary gland secretions.
Materials and Methods
Thirty Holstein cows were stratified by parity and randomly
assigned to the Tasco TM (170 g/d) supplemented group
or control diet. Treatments were initiated 21 d prior to expected
parturition and fed until calving. Tasco TM supplemented
cows were on the diet a minimum of 8 and a maximum of 42
d with a mean of 22 d. All cows were offered 21 lb of
sorghum silage, ad lib hay, and 5 lb of a commercially prepared
dry cow grain supplement.
Blood samples from cows and calves, as well as mammary
gland secretion (MGS) samples were obtained at parturition
and at d 1 post partum. After calving, the cow and calf
were separated before the calf nursed. Approximately two
liters of bulk colostrum were collected and fed to the calf
immediately after the calf was sampled. One-half liter of bulk
colostrum was obtained at parturition and one day later, and
centrifuged at 1000 X g at room temperature for 10 min. The
supernate was removed and the pelleted cells were washed
twice in phosphate-buffered saline (PBS).
At parturition and one day later, peripheral blood was
collected from cows and calves into vacutainer tubes containing
acid citrate dextrose as an anticoagulant.
Mononuclear cells were isolated by lysis of red blood cells
with Tris-buffered ammonium chloride and washed twice
in PBS.
Samples of washed milk cells and peripheral blood
mononuclear cells (1 X 10 6 /sample) were immunofluorescently
labeled with a panel of mouse monoclonal antibodies
specific for bovine leukocyte cell surface molecules using an
1 Department of Animal Science, Fayetteville
2 Department of Poultry Science, Fayetteville
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