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

Figure 4: Average test day milk fat and milk protein percentages for supplementation
treatments.
Fat (%)
Protein (%)
7
6
5
4
7
6
5
4
*
*
*
-2 12 26 40 54 68 82
-2 12 26 40 54 68 82
Day of trial
* Least squares means within a test day are different (P < 0.05).
63
Unsupplemented
Supplemented
Unsupplemented
Supplemented
Estimated total milk production over the 82-d trial and average milk fat and milk protein
percentage of the total milk produced is presented in Table 3. Early lactation ewes produced
more (P < 0.01) milk (+ 41.3 kg), FCM (+ 39.0 kg), and FPCM (+ 37.3 kg) than late lactation
ewes during the trial period. Ewes in both stages of lactation produced milk with a similar fat
percentage, and early lactation ewes produced more (P < 0.01) milk fat than late lactation ewes
(7.77 vs. 5.31 kg, respectively) due to the greater milk production. Late lactation ewes had a
similar milk protein percentage compared to early lactation ewes, but they produced less (P <
0.01) total milk protein (4.61 vs. 6.27 kg, respectively) due to lower milk production.
Even though supplemented ewes had greater mean values for total milk production than
unsupplemented ewes (milk: + 19.7 kg; FCM: + 14.0 kg; FPCM: + 13.3 kg), the differences
between supplementation treatments were not significantly different from zero (Table 3).
Since supplemented ewes produced more (P < 0.01) milk than unsupplemented ewes (Table
2) on individual test days, the lack of statistical significance between supplementation
treatments for total milk production is probably due to the fewer number of observations for
the latter trait. As in the case of total milk production, total fat and total protein production
were greater for supplemented than unsupplemented ewes, but the differences were not
statistically significant.
*