Researches On Variation Of The Rumination And Its Influencing Factors In Lactating Cows

Rumination is closely related to the performance, reproduction, stress, anddisease in cows. The variation of ruminating time reflects the health status of dairycows. In recent years, regard to the rumination, feeding，communication and otherbehaviors gradually were researched, and some foreign studies have been published.However, in domestic less researches is available about the rumination and itsrelationship with other factors. Three different experiments were designed to studyrumination time and its relationship with some factors, which was aimed atproviding references to further studies and applications.The first experiment was to investigate the relationship between dry matterintake (DMI) and rumination time (RT), lying behavior (lying time and frequency),and milk yield in dairy cows. Data were collected from32mature Holstein dairycows (16primiparous, PR;16multiparous, MP, parity=1.7±0.8; milk production=10,019±166kg/year; mean±SD).DMI was monitored using Insentec feed bins(Insentec BV, Marknesse, the Netherlands). RT was monitored electronically usingHR-Tags (SCR Engineers Ltd., Netanya, Israel). Lying behavior was monitoredusing an activity logger (HOBO Pendant G; Onset Computer Corp.,Cape Cod, MA).Data was analyzed by the R programming language (Mathsoft, USA). According tothe level of RT, cows were assigned to the low-RT group (L: RT=277.65±39.61min/d;8PR and8MP) and the high-RT group (H: RT=413.21±46.89min/d;8PR and8MP). One-way ANOVA was used to analyze the difference between H and L groups.There was no significant difference between H and L group in DMI (H:20.59±2.63 kg/d; L:20.31±3.34kg/d; P=0.79), lying behavior (lying time, H:690.44±155.46;L:773.00±163.41, P=0.20; Lying frequency, H:11.25±3.14, L:10.79±3.39, P=0.43),and milk yield (H:32.04±6.00kg/d; L:32.15±4.31kg/d; P=0.95). Pearson correlationwas used to describe associations among DMI, RT, lying behavior (lying time andfrequency) and milk yield. Multiple Linear Regression analysis was performed withlm package of the R programming language. A significant positive relationshipexisted between DMI and milk yield (P=0.01, r2=0.93). Rumination time (P=0.34)and lying behavior (Lying time, P=0.36; and Lying frequency, P=0.14) were notaffected by DMI. Only the milk yield (P<0.01) was significantly affected by DMI,and the equation was DMI=8.98+0.36*MY, R2=0.39, and which MY representsmilk yield. These results indicate that milk yield can be used to estimate DMI;however, RT and lying behavior are independent variables and not the suitableindicators for DMI.The second experiment was described the regular pattern of rumination timeand milk yield around estrus in dairy cows. The data came from a10,000cows dairyfarm. Rumination time and milk production around estrus were analyzed. Accordingthe location of the farm, time factor was divided two seasons, cold and warm season,respectively. The results showed that rumination time decreased in estrus, from423.0min/d to358.1min/d. Parity (P<0.01) was significantly affected the ruminationtime decreasing, but season (P=0.34) was a non-significant factor. With the parityincreased, the extent of rumination time decreased got smaller. On the other hand,there was no significant difference on the milk yield betweenbefore and in estrus(P=0.93). But, the milk yield after estrus was significant decreased (P<0.01), and thedecreased milk yield of different parity cows was significant difference. The milkyield declination of cows over parity3was the most decreased.The third experiment was to study the effect of different disease on ruminationtime in dairy cows. The data came from the10,000cows dairy farm located in the northeast of China. Rumination time was analyzed around disease period. Thediseases were separated seven types, digestive tract diseases, reproductive diseases,mastitis, inflammation, udder trauma, hoof diseases andketosis. The declination ofrumination time was founded during sickness. Moreover, digestive tract diseasescontributed the most rumination time declination, and reproductive diseases were behind,and mastitis and inflammation were normal, followed by udder trauma and hoof diseases,and with the minimal impact on rumination time declination wasketosis.