Table 5. Comparative performance of milk composition in Holstein and Jersey cows by THI range
Item | Breed | THI | Total1) | PSEM | p-value |
61–63 | 64–66 | 67–69 | 70–72 | 73–75 | 76–78 | 79–81 | 82–84 | THI | Breed | THI × Breed |
Fat (%) | Holstein | 3.49 | 3.81 | 3.85 | 3.64 | 3.96 | 3.61 | 3.64 | 3.37 | 3.67 | 0.06 | 0.428 | < 0.001 | 0.373 |
Jersey | 5.02 | 4.74 | 4.71 | 5.20 | 4.45 | 4.46 | 4.74 | 4.28 | 4.70 | 0.10 | 0.389 |
Protein (%) | Holstein | 3.20 | 3.16 | 3.18 | 3.09 | 3.13 | 3.07 | 3.01 | 2.88 | 3.09 | 0.03 | 0.111 | < 0.001 | 0.093 |
Jersey | 3.89a | 3.79a | 3.85a | 3.78a | 3.44b | 3.46b | 3.42b | 3.20b | 3.61 | 0.04 | 0.000 |
Lactose (%) | Holstein | 4.85 | 4.87 | 4.87 | 4.82 | 4.84 | 4.81 | 4.82 | 4.55 | 4.81 | 0.02 | 0.111 | 0.004 | 0.249 |
Jersey | 4.71ab | 4.67ab | 4.43b | 4.63ab | 4.84a | 4.83a | 4.80a | 4.39b | 4.69 | 0.04 | 0.023 |
TS (%) | Holstein | 12.27 | 12.57 | 12.62 | 12.27 | 12.63 | 12.21 | 12.19 | 11.55 | 12.30 | 0.08 | 0.088 | < 0.001 | 0.443 |
Jersey | 14.36 | 13.93 | 13.71 | 14.31 | 13.43 | 13.45 | 13.66 | 12.59 | 13.71 | 0.13 | 0.053 |
Values are expressed as the mean ± SEM of 7 dairy cows in each group.
Values are the average of data for both THI ranges in the same breed.
Denote comparisons made within (same breed) rows.
THI, temperature-humidity index; PSEM, pooled standard error of the mean.