Ground johnson grass hay and long hay addition to total mixed rations for dairy cows

Abstract

Two total mixed rations (TMR) were compared; both contained 20% ground hay, of either Johnson grass (J) or pajon and star grass (PS); both included 20% coarsely chopped PS hay and 60% concentrates; and both were analyzed to be about 13% crude protein. Treatments I and II consisted 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, respectively ( 2 x 2 factorial). Feed was offered between evening and morning milkings only. Ten adult Holstein cows grouped 2 x 2 and 2 x 3 were used in a 4 x 4 Latin square experiment with 2-wk comparison periods. No significant interactions of treatment factors were found. Comparing the effects of TMR-J vs. TMR-PS and no long hay vs. long hay addition, means 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 efficiency (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). General mean rectal temperature (RT), shortly past noon, was 39.8° ± 0.3°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.