To study the salt-licking behavior of steers in three different levels of environmental enrichment, seventy-one Japanese Black X Holstein steers were allocated, in 2 repetitive experiments, to 3pens (6.0 X 9.5 m) : Pen C (control, n = 11 and 12) consisted of a feeding alley for grain feed, a trough for dry hay, a water bowl and a resting space ; Pen D (n = 12 and 12) was enriched with a drum can (Φ58 X H 90 cm) that can contain hay to the control pen ; Pen GD (n = 12 and 12) was enriched with a drum can put around an artificial turf (30 X 120 cm) for grooming. A salt-mineral block ( 5 kg) was put on the feeding alley of each pen at 4.5 months after introduced from a market. Behavioral observations were made for 2 h at 10 min intervals after morning and evening feedings. Then blood sampling and measuring body weight were performed. The number of steers that licked a salt-mineral block was 16 in Pen C, 10 in Pen D and 11 in Pen GD over the observation period, and was not significantly different among pens. As for the duration of each salt-licking behavior, 81% of salt-licking behaviors was less than 20 min. The behaviors observed just before salt-licking were mainly eating hay (25.9%) and resting (22.4%). On the other hand, behaviors observed just after salt-licking were resting (28.3%) and eating hay (21.7%).The number of salt-licking behaviors correlated positively with the number of resting (r=0.25, P<0.05) and ruminating (r=0.28, P<0.05) behaviors and serum insulin concentrations (r=0.41, P<0.05). Plasma glucose concentrations were higher in the steers that licked salt-mineral blocks than in the steers that never licked them (P<0.05). In conclusion, licking salt-mineral blocks could have positive effects, irrespective of environmental enrichment levels, on the digestion and metabolism of steers by encouraging their resting and ruminating behaviors, and insulin secretion.
To evaluate for an effect of grazing on a health in dairy cattle, the veterinary records from Agricultural Cooperation were analyzed with milk production records and feeding styles with or without grazing for each dairy farms at northern area in Hokkaido, Japan. The veterinary records and milk production performance for each farm were from Research Center of Agriculture and Science in this area. Number of cattle kept, area of grassland, grazing or zero-grazing were surveyed by a postal questionnaire method for all dairy farms, about 100, in this area. Forty-six questionnaires had been obtained. In these farms, means of milk yield, number of milking cows, area of grazing pastures and number of medical treatments by veterinarians were 8,127.2 kg/305d, 71.7 cows, 8.6 ha and 1.2 time/year, respectively. The number of medical treatments by veterinarians/cow/year were positively related to the milk yield /cow/305d. (P<0.05) and negatively related to the area of grassland/farm (P<0.05). From this 46,32 farms were picked up for further analysis. Grazing were used in 24 farms, in which 7 farms were of all-day-grazing except milking time (group G), 17 were grazed their cattle during day time (group TG). Remained 9 had kept their animals in their cow-shed for a whole day (group B). There was no statistical difference of milk yield/cow among groups. The number of medical treatments (/cow/year) for milk organs by veterinarians was a little high in the group G and treatment frequencies for a foot and hoof were relatively low in groups G and B, though those differences among groups were not significant. Frequency of veterinary treatments (/cow/year) for conception, calving and reproductive organs was lower in group G (0.22) than groups TG (0.41) and B (0.42) significantly (P<0.05).