Abstract #419
Section: Ruminant Nutrition
Session: Ruminant Nutrition IV
Format: Oral
Day/Time: Tuesday 2:30 PM–2:45 PM
Location: 317
Session: Ruminant Nutrition IV
Format: Oral
Day/Time: Tuesday 2:30 PM–2:45 PM
Location: 317
# 419
Heat stress influences the rumen microbiome of mid-lactation dairy cows.
D. P. Bu1,6, S. C. Li2, L. Wang*3, L. Ma1,5, L. H. Baumgard4, Z. T. Yu3, 1State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing,China, 2Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada, 3Department of Animal Sciences, The Ohio State University, Columbus, OH, 4Department of Animal Science, Iowa State University, Ames, IA, 5CAAS-ICRAF Joint Lab on Agroforestry and Sustainable Animal Husbandry, World Agroforestry Centre, East and Central Asia, Beijing, China, 6Hunan Co-Innovation Center of Safety Animal Production, CICSAP, Changsha, Hunan, China.
Key Words: dairy cow, heat stress, rumen microbiome
Heat stress influences the rumen microbiome of mid-lactation dairy cows.
D. P. Bu1,6, S. C. Li2, L. Wang*3, L. Ma1,5, L. H. Baumgard4, Z. T. Yu3, 1State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing,China, 2Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada, 3Department of Animal Sciences, The Ohio State University, Columbus, OH, 4Department of Animal Science, Iowa State University, Ames, IA, 5CAAS-ICRAF Joint Lab on Agroforestry and Sustainable Animal Husbandry, World Agroforestry Centre, East and Central Asia, Beijing, China, 6Hunan Co-Innovation Center of Safety Animal Production, CICSAP, Changsha, Hunan, China.
Heat stress (HS) affects rumen fermentation of lactating dairy cows. This study examined the rumen microbiome in response to HS. Four multiparous Holstein dairy cows (101 ± 10 DIM; 38 ± 2 kg of milk/d) were each randomly assigned to 4 environment chambers in a crossover design. Cows were either subjected to HS [HS: 36°C with light and 32°C without light; THI = 87.2 and 81.8, respectively] or kept under thermal neutral conditions [TN: 20°C; THI = 65.5] for 9d of adaptation and then for another 9d of pair-feeding to eliminate confounding effects of dissimilar feed intake. A 30d washout period was allowed between the 2 periods. Rumen fluid was collected twice at 0400 (before feeding) and 1000 (after feeding) on d9 of each period using an oral probe, and DNA was extracted. The V4-V5 hypervariable region of the 16S rRNA gene of bacteria, ITS1 sequences of fungi, and 18S rRNA gene of protozoa were amplified and sequenced using MiSeq. After sequence processing and analysis using QIIME, α and β diversity measurements were estimated. Bacterial community composition (at phylum and genus levels) and predictive metagenome profiles were compared between HS vs. PFTN using the nbinomWaldTest method of DESeq. HS increased total VFA concentration (by 45.3%, P < 0.05) before feeding. Alpha diversity of bacterial and protozoal communities was not affected by HS. The richness of fungal community was significantly lower in PFTN (P < 0.05) than in HS. PCoA analysis based on weighted UniFrac distance revealed difference in bacterial and protozoal communities (P < 0.05), while NMDS analysis using Bray-Curtis dissimilarity showed difference in fungal community between HS and PFTN. The phyla Chloroflexi and Actinobacteria were less predominant in HS than in PFTN (P < 0.05). Shuttleworthia, Anaeroplasma, and Ruminococcus were the most predominant genera among 99 affected genera in HS cows (P < 0.05). For protozoa, HS increased the relative abundance of Entodinium but decreased that of the Isotricha and Ophryoscolex. For fungi, both the phyla Ascomycota and Glomeromycota were significantly higher in HS cows than in PFTN cows (P < 0.05). Collectively, HS can directly affect ruminal microbiome independent of its effect on DMI, and different ruminal microbes respond to HS differently.
Key Words: dairy cow, heat stress, rumen microbiome
