GROUND JOHNSON GRASS HAY AND LONG HAY ADDITION TO TOTAL MIXED RATIONSFOR DAIRY-COWS

Two total mixed rations (TMR) were compared; both contained 20% ground hay, of either johnson grass (J) or pajon and star grass (PS); both i ncluded 20% coarsely chopped PS hay and 60% concentrates; and both wer e analyzed to be about 13% crude protein. Treatments I and II consiste d of TMR-J without and with addition of 1.5 kg per head daily of long PS hay; III and IV, of TMR-PS without and with said addition, respecti vely (2 x 2 factorial). Feed was offered between evening and morning m ilkings only. Ten adult Holstein cows grouped 2 x 2 and 2 x 3 were use d in a 4 x 4 Latin square experiment with 2-wk comparison periods. No significant interactions of treatment factors were found. Comparing th e effects of TMR-J vs. TMR-PS and no long hay vs. long hay addition, m eans were: daily dry matter intake (DMI), 19.89 vs. 19.65 and 19.17 vs . 19.77 kg; daily milk production, 18.46 vs. 18.89 and 18.48 vs. 18.87 kg; milk fat percentage, 2.64 vs. 2.71 and 2.60 vs. 2.76; feed effici ency (4% fat-corrected milk/DMI), 0.736 vs. 0.777 and 0.741 vs. 0.772, respectively. Thus, long hay addition increased milk fat content by 0 .16%, and TMR-PS exceeded TMR-J in efficiency by 0.041 (P<0.05). Gener al mean rectal temperature (RT), shortly past noon, was 39.8 degrees /- 0.3 degrees C (standard deviation, SD); liveweight (LW) mean, 590 /- 43 kg (SD). Milk yield and RT were unrelated. In conclusion, J hay gave satisfactory results in the TMR; long hay addition improved milk fat content; and limiting feeding to the cooler hours helped mitigate animal hyperthermia.