great lakes dairy sheep symposium - the Department of Animal ...

Table 3: Total milk production and milk composition during the trial of stage of lactation
and supplementation treatments.
Stage of lactation a Supplement level b
Late Early No supplement Supplement
No. of ewes 10 46 28 28
mean ± se mean ± se P < mean ± se mean ± se P <
Milk, kg 95.6 ± 12.7 136.9 ± 5.9 0.0047 106.4 ± 9.9 126.1 ± 9.9 0.1672
Fat % 5.58 ± 0.25 5.79 ± 0.12 0.4671 5.86 ± 0.20 5.50 ± 0.20 0.1983
Fat, kg 5.31 ± 0.67 7.77 ± 0.31 0.0016 6.16 ± 0.52 6.91 ± 0.52 0.3141
Protein % 4.80 ± 0.14 4.65 ± 0.06 0.3172 4.85 ± 0.12 4.60 ± 0.12 0.1033
Protein, kg 4.61 ± 0.52 6.27 ± 0.24 0.0059 5.09 ± 0.41 5.80 ± 0.41 0.2254
FCM, kg 85.9 ± 10.8 124.9 ± 5.0 0.0018 98.4 ± 8.4 112.4 ± 8.4 0.2401
FPCM, kg 84.1 ± 10.3 121.4 ± 4.8 0.0020 96.4 ± 8.1 109.7 ± 8.1 0.2419
a Late lactation ewes are 136 ± 9 DIM, early lactation ewes 21 ± 10 DIM.
b Supplement received 0.80 kg DM/d.
Pastures. Herbage availability in each paddock ranged from 854 to 2561 kg DM/ha with an
average of 1504 kg DM/ha. Stocking rates were adjusted to allow for at least 2.84 kg DM/ewe/d.
Post-grazing herbage allowance, measured once per week, was always greater than 4.24 kg
DM/ewe, indicating that ewes had sufficient pasture DM available. Herbage mass per hectare
and per ewe before grazing was highest at the beginning of the season and decreased towards the
end of the summer.
The quality of available pasture remained high throughout the trial as a result of pasture
management, which included intensive rotational grazing and clipping paddocks after grazing.
Fiber and protein levels varied throughout the trial as a result of changes in pasture composition,
including changes in the relative proportions of grass and legume. Pasture CP averaged 24.2 %
but ranged from 16.6 to 30.6 %, and NDF averaged 36.0 % and ranged from 22.6 to 51.9 %
(Table 4). The paddocks with the most kura clover and least orchardgrass had the highest CP
and lowest NDF values, and the paddocks with the greatest percentage of grass and the least kura
clover had the lowest CP and highest NDF values.
Table 4: Mean pasture quality measurements.
n mean ± s.e.
Neutral detergent fiber a 30 36.0 ± 9.1
Crude protein a 30 24.2 ± 4.1
Lignin b 3 3.2 ± 0.4
Digestibility c 40 66.9 ± 4.3
a Forage samples collected from May 25 to August 15.
b Forage sample collected during fecal sampling period for dry matter intake estimation.
c Calculated based on acid detergent lignin % of forage and individual ewe fecal sample.
Intake estimates. Estimates of pasture DMI and total DMI are presented in Table 5.
Pasture DMI was not significantly different between supplementation or stage of lactation
treatments. Pasture DMI averaged 1.63 kg/d for unsupplemented ewes and 1.53 kg/d for
supplemented ewes. Early lactation ewes consumed, on average, more pasture DM than late
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