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.