Goetz B M, Lefler J, Abeyta M A, Horst E A, Mayorga E J, Al-Qaisi M, Rodriguez-Jimenez S, Martino C, Izzo A, La R, Green H B, Moore C E, Embree M, Baumgard L H
Department of Animal Science, Iowa State University, Ames 50011.
Ascus Biosciences Inc., San Diego, CA 92121.
JDS Commun. 2021 Mar 12;2(3):118-122. doi: 10.3168/jdsc.2020-0002. eCollection 2021 May.
This study evaluated the effects of a microbial feed supplement (MFS; Galaxis, Ascus Biosciences Inc.) comprising 2 native rumen microbes on performance parameters in mid-lactation dairy cows. Forty-six lactating primiparous and multiparous Holstein cows [629 ± 62 kg of body weight, mean ± standard deviation (SD); parity 1.64 ± 0.49; 119 ± 38 days in milk; 45.11 ± 3.81 and 52.73 ± 4.77 kg/d of milk yield for primiparous and multiparous, respectively] were enrolled in a study containing 3 experimental periods (P). During all periods, enrolled cows were fed the same base total mixed ration (TMR) ad libitum once daily. During P1 (7 d), baseline data were obtained for covariate analysis. At the beginning of P2 (60 d), cows were assigned to 1 of 2 dietary treatment groups in a randomized complete block design to balance for milk yield (MY), parity, and days in milk: (1) a control diet (CON; base TMR; n = 23), or (2) a control diet supplemented with 5 g/d of MFS (MFS; n = 23). Sample size was determined based on previous, unpublished results involving this MFS; a 3-kg difference between groups with a SD of 3.5 kg could be detected with sufficient power (0.81) using a total sample size of 46 cows. Treatment was top-dressed and hand-mixed into the top one-third of the TMR. During P3 (7 d), no treatment was administered, and all cows were fed the base TMR. When analyzing all cows in the data set, MFS had little to no effect on performance. However, modeling revealed that the fixed effect of covariate milk production level had a significant effect on the response of MY and ECM, and further investigation of the data revealed that treatment effectiveness in P2 correlated with milk production during P1. Cows were retrospectively categorized into 2 milk production groups (MPG) balanced for parity: MPG1 (i.e., <53 kg/d of ECM during P1; n = 34) or MPG2 (i.e., ≥53 kg/d of ECM during P1; n = 12). Energy-corrected milk was increased by 4.4% in MFS-administered MPG1 cows compared with CON cows during P2. Although there were no significant effects of MFS on production variables for MPG2 cows, MY tended to be decreased by 3.9% in MFS-administered cows compared with CON cows. Further investigation is needed to understand production level response differences and the effect of supplemented native rumen microbes on animal health and productivity.
本研究评估了一种包含2种天然瘤胃微生物的微生物饲料添加剂（MFS；Galaxis，Ascus生物科学公司）对泌乳中期奶牛生产性能参数的影响。46头泌乳初产和经产荷斯坦奶牛[体重629±62千克，平均值±标准差（SD）；胎次1.64±0.49；产奶天数119±38天；初产和经产奶牛的日产奶量分别为45.11±3.81和52.73±4.77千克]被纳入一项包含3个试验期（P）的研究。在所有试验期内，给纳入的奶牛每日自由采食一次相同的基础全混合日粮（TMR）。在P1期（7天），获取基线数据用于协变量分析。在P2期（60天）开始时，奶牛被随机完全区组设计分配到2个日粮处理组中的1组，以平衡产奶量（MY）、胎次和产奶天数：（1）对照日粮（CON；基础TMR；n = 23），或（2）添加5克/天MFS的对照日粮（MFS；n = 23）。样本量根据此前未发表的涉及该MFS的结果确定；使用46头奶牛的总样本量，有足够的检验效能（0.81）可检测出组间相差3千克、标准差为3.5千克的差异。处理方法是将添加剂撒在TMR顶部并手工混合到顶部三分之一处。在P3期（7天），不进行任何处理，所有奶牛都饲喂基础TMR。在分析数据集中的所有奶牛时，MFS对生产性能几乎没有影响。然而，模型显示协变量产奶水平固定效应对MY和能量校正乳（ECM）的反应有显著影响，对数据的进一步研究表明，P2期的处理效果与P1期的产奶量相关。奶牛被回顾性地分为2个产奶量组（MPG），并平衡胎次：MPG1（即P1期ECM<53千克/天；n = 34）或MPG2（即P1期ECM≥53千克/天；n = 12）。在P2期，与CON组奶牛相比，给MPG1组奶牛饲喂MFS后能量校正乳增加了4.4%。虽然MFS对MPG2组奶牛的生产变量没有显著影响，但与CON组奶牛相比，给MPG2组奶牛饲喂MFS后MY有降低3.9%的趋势。需要进一步研究以了解产奶水平反应差异以及添加天然瘤胃微生物对动物健康和生产力的影响。
