The objective of this study was to evaluate cooling to lessen the effects of heat stress during the last 3 wk of gestation on performance and behavior of multiparous Holstein cows. Twenty nonlactating cows were randomly assigned to treatments approximately 21 d before their expected calving date based on mature equivalent milk production and parity. Treatments were only imposed during the last 3 wk of gestation and included heat stress (HT; n=10) and cooling (CL; n=10), both under a similar photoperiod (14 h of light and 10 h of dark). Dry cows were housed in a sand-bedded stall with the stall areas for CL cows equipped with sprinklers and fans that were on from 0700 to 1900 h, whereas those for the HT cows were not. After parturition, all cows were housed in a barn with cooling devices. Rectal temperatures were measured daily at 1400 h and respiration rates were recorded by counting the flank movements for 1 min at 1500 h on odd days over the last 3 wk of gestation to calving. Daily dry matter intake was measured from -21 d relative to expected calving to 21 d after calving and milk production was recorded daily up to 180 d in milk. Behavioral changes of dry cows were studied continuously for 24 h at -10 d relative to expected calving. The average temperature-humidity index during the last 3 wk of gestation was 69.7 and was not significantly different between treatments. Heat-stressed cows exhibited greater rectal temperatures (39.5 vs. 39.2°C), greater respiration rates (70.4 vs. 63.3 breaths/min), and decreased dry matter intake (13.7 vs. 15.5 kg/d) compared with CL cows. Compared with HT cows, CL cows produced more milk during 180 d in milk (40.5 vs. 44.6 kg/d). Heat stress decreased ruminating (243.2 vs. 282.5 min/d) and chewing times (390.6 vs. 448.7 min/d) at -10 d before calving. The CL cows had shorter standing times than their HT counterparts (390.4 vs. 474.0 min/d). These results confirm that heat stress abatement in the late gestation period improves performance of dairy cows in subsequent lactation.

This study evaluated the effects of Lactobacillus buchneri (LAB) and orange pulp (OP) supplementation on chemical composition, in vitro and in situ degradability, dry matter (DM), pH and aerobic stability of alfalfa silage. Treatments were 1) alfalfa without any additive (control), 2) alfalfa + OP (70% alfalfa mixed with 30% fresh OP, LAB0), 3) treatment 2 with 1.5 g LAB/ton (LAB1), 4) treatment 2 with 3 g LAB/ton (LAB2) and 5) treatment 2 with 4.5 g LAB/ton (LAB3). Treatments were replicated three times in laboratory mini silos for 90 d in a closed barn with a ambient temperature (15 to 18 o C). As a result of this study, the experimental treatments did not affect on DM of silage at the end of the ensiling period. Control treatment had the highest pH (4.5) among the experimental treatments ( P<0.05). Supplementation alfalfa with OP resulted in significant increase in water soluble carbohydrate (WSC) and total volatile fatty acids (VFAs) ( P<0.05). Treating alfalfa silage with OP and LAB improved aerobic stabilities of treatments significantly, as compared to LAB0. Supplementation of silage with OP and bacterial inoculant increased DM digestibility. These findings indicated that LAB can improve the aerobic stability and quality of silage in laboratory silos and also, OP and LAB might improve silage quality and cause better silage management in the farm.