Effect of Temperature Humidity Index (THI) on resting pattern of dairy cows in different regions of Sri Lanka.

The ability to spend time resting is extremely important for dairy cattle welfare. Through this study, lying behaviour of dairy cows in to Up-Country (UP), Mid-Country (MC), Coconut-Triangle (CT) and Western-Province (WP) of Sri Lanka was studied to get an insight into their resting pattern. Resting pattern was assessed in 170 Holstein-Friesian/ Jersey crossed, tie-stalled lactating cows (UP = 49, MC = 49, CT = 48 and WP = 24) using electronic data loggers. Appropriate resting behaviours were attained in UP and MC regions, with longer lying time (11.7, 11.3 h/day) and lying bout durations (78.0, 84.9 min) respectively, where lower THI ranges were observed compared to other regions. WP and CT resulted with lower lying times (9.00, 9.26 h/day) and lying bout durations (48.3, 64.3 min) respectively with higher THI. There is a slight variation of the environmental temperature of each region with the time period of experiment. Cows in all regions prefer to lie on their left side (UP-6.1, MC-6.1, CT-4.4, WP-4.7 h/d) and with significant differences (P<0.05) between MC-WP, MC-CT, UP-CT and UP-WP. A negative significant (P<0.05) correlation was observed between THI and lying behaviours. There were significant effects of time (hour) and time × region interaction (P<0.05) on the lying down pattern. More lying down was observed in late night and early morning with a peak rest around the hours of 21:00-05:00. Overall, according to the results of the current study, the existing environmental conditions of four regions affected the resting pattern of dairy cows and, identification of possible mechanisms to modify the environment to enhance cow comfort is vital.

Effect of rubber and concrete flooring on resting behavior, hock injuries, and milk production of primiparous Friesian crossbred dairy cows housed in a free-stall barn in Mid-Country, Sri Lanka.

The floor surface of the cubicle is a detrimental factor on cow comfort. The effects of two floor types, rubber and concrete, on dairy cow comfort and milk production were compared for a period of 13 weeks. Fourteen Friesian crossbred dairy cows with an average body weight of 425.67 ± 61.12 kg (mean ± SD), nose to tail body length of 2.07 ± 0.15 m, rump height of 1.29 ± 0.02 m, hook bone width of 0.48 ± 0.05 m, and body condition score (BCS) of 4.13 ± 0.44 were used, with seven cows per flooring treatment. The cows produced a mean of 15.93 ± 4.03 l/cow/day and a constant feeding plan was practiced. The swelling and wound severity of hocks diminished (P < 0.05) starting at the third and tenth weeks, respectively. Daily lying time/h (concrete: 9.67 ± 1.24, rubber: 10.60 ± 0.69, P = 0.046) and average duration of lying bouts/min increased (concrete: 58.16 ± 7.74, rubber: 65.66 ± 9.85, P = 0.050) starting from the twelfth week on rubber bedding. Prevalence of mastitis, lameness, and cow cleanliness remained unchanged on floor treatments. A progressive increase in daily milk production/l (concrete: 13.37 ± 1.46, rubber: 16.67 ± 2.24, P = 0.007) of cows in rubber bedding was observed at the fourth week of the experiment. Hence, the current study suggests that the use of softer bedding such as rubber mats could improve cow comfort and daily milk production of cows.