This study aimed to reveal the effects of direct exposure to cold weather under grazing in winter (GW) on the health of Japanese Black beef cattle, as assessed using physiological, immunological, and behavioral parameters. Ten Japanese Black beef cattle (328 ± 45 kg, 7.6 ± 3.4 years of age) were used in this experiment. In winter, five of the 10 cattle grazed for 2 months in a 1.8 ha pasture (GW), and the remaining cattle were fed under confined conditions with tethering (control [CT]). The two groups were fed similar feed during the experiment, except for the grazing forage. Blood samples were collected approximately every 2 weeks. The numbers of neutrophils and monocytes and antioxidant enzyme activity were higher in the GW group than in the CT group (p < 0.05). The proportions of CD4‐single‐positive cells were lower in GW cattle than in CT cattle (p = 0.06). This study showed that direct exposure of beef cattle to cold weather under GW enhanced the levels of circulating neutrophils and monocytes and contributed to the kinetic homeostasis of lymphocytes but also activated antioxidant enzymes due to an increase in oxidative stress.

The aim of this study was to reveal the potential impact of botanically diverse pasture on the nutritional, physiological, and immunological status of grazing cattle using multifaceted indices. Ten Japanese black beef cows (325.5 ± 40.6 kg of body weight [BW], 7.9 ± 3.8 years of age) were used in this experiment. Five of them grazed on a 1.8‐ha grassland (botanically diverse pasture: DP) that was composed of sown grassland and grazable forestland (approximately 34 plant species). The other five cows grazed on 1.0 ha of sown grassland with only a few plant species (botanically monotonous pasture: MP, approximately 5 plant species) for 2 months. Blood samples were collected approximately every 2 weeks. In DP cows, the hemoglobin (HGB) concentration, hematocrit (HCT) ratio, and superoxide dismutase (SOD) activity increased linearly after the start of grazing, as did plasma sodium (Na), calcium (Ca), and potassium (K) concentrations. Urea nitrogen (UN) levels were higher in DP than in MP cows throughout the grazing period, whereas in MP cows, the red blood cell (RBC) count, HGB concentration, and HCT ratio decreased quadratically after the start of grazing. The DP cows gained more BW than the MP cows throughout the grazing period. Thus, the increased intake and/or the change in the ingested plant species in DP cows might have promoted the increase in the plasma UN concentration. In summary, the present study showed that grazing in botanically diverse pasture improved the nutritional and physiological status of cows; however, it aggravated the imbalance of protein and energy intake induced by grazing within 2 months.

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Grazing goats have potential for use in managing abandoned fields. However, it is unclear how long‐term grazing affects goats as a result of vegetational changes in abandoned fields. This study aimed to assess the dynamics of vegetation quality and quantity and the nutritional status of goats for five years in an abandoned field at different stocking rates: high stocking rate (HS: 30–33 goats/ha) and low stocking rate (LS: 14 goats/ha). In five years, the dominant plant species changed from bamboo (Phyllostachys edulis) to tufted grass species at the HS, whereas dwarf bamboo (Pleioblastus argenteostriatus) dominated throughout the five years at the LS. The annual plant biomass at both stocking rates was similar and varied from year to year. Crude protein content in the goats' diet did not show any seasonal or annual trend regardless of the stocking rate. Neutral detergent fiber content in the HS diet did not show any seasonal or annual trend; however, that in the LS diet linearly increased with the grazing year. The dry matter (DM) intake for goats at the LS decreased linearly with the grazing year (p < 0.05), whereas that for goats at the HS did not show any trend. The DM digestibility was higher for goats at the HS than for goats at the LS (p < 0.05). Serum parameters did not show a negative nutritional status of the goats over the study years. Annual daily gain was positive throughout the grazing years regardless of the stocking rate. Consequently, within the stocking rate range studied here, long‐term goat grazing changes the quality of vegetation in an abandoned field; however, goats can maintain their nutritional status and body weight for five years. Thus, goat grazing is a feasible way to control abandoned vegetation over the long term.

No abstract