Type: dissertation
Abstract: Two studies were conducted on the relationship between ruminal mat consistency (RMC) and ( 1) calf mortality or (2) immunity.Assessment of RMC was by ten repeated manual compressions of the middle rumen; good-RMC showed no fluid bounce-back (FBB), while poor-RMC showed FBB.The first study examined whether RMC affected calf mortality.Monthly feeding management guidance (FMG) was implemented for 5 years on a commercial farm with Holstein-Friesian × Japanese black calves, directing increased forage consumption for poor-RMC calves aged 50-180 days.Compared to 35 control farms, the FMG period showed significantly lower total mortality (3.8% vs. 0.8%, P < 0.001, OR = 4.7) and lower respiratory mortality (2.3% vs. 0.1%, P < 0.001, OR = 18.3).The second study tested the hypothesis that RMC affects calf immunity.Peripheral blood of good-RMC (n = 6) and poor-RMC (n = 6) calves was compared.Good-RMC showed higher phagocytosis in monocytes (P = 0.05, r = 0.63) and granulocytes (P = 0.02, r = 0.78), and higher numbers of CD4 + (P = 0.07, r = 0.58), CD8 + (P = 0.07, r = 0.60), and B-cells (P = 0.03, r = 0.62).In mRNA expression, good-RMC showed lower TNF-α (P = 0.02, r = 0.70), IL-1 (P = 0.09, r = 0.49), IL-12 (P = 0.04, r = 0.59) and IL-10 (P = 0.13, r = 0.44), and higher IL-16 (P = 0.07, r = 0.53) compared to poor-RMC.These results suggest that RMC affects calf mortality and immunity, emphasizing the importance of feeding management in improving sustainability.
Author: Abe, Shinsuke
Institution: University of Miyazaki
Language: English
Topic: Animal health and immunology
Subfield: Animal Science and Zoology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W7208403993