AIMTo investigate the effects of cysteamine compound (Lactonin) on milk production of late-lactating cows during hot summer when the temperature humidity index (THI) was higher than 76 and cows were suffered from heat stress.

METHODSIn this experiment 96 black and white dairy cows, based on milk yield (M) prior to the experiment, were assigned into 4 groups (G): G1 (M < 24 kg/d), G2 (24 < M< 28 kg/d), G3 (28 < M < 32 kg/d) and G4 (M > 32 kg/d). Each group (n = 24) was further divided into subgroups of Lactonin (3000 U/d) treatment (LT, n = 49) and control (n = 47).

RESULTSIn G1 of LT, the rectal temperature decreased (P < 0.05), milk yield, fat-corrected milk, milk fat and feed conversion rate (FCR) increased (P < 0.05). These were companied with trendy of higher milk protein and lower somatic cell count. With whole LT cows (n = 49), the mean milk fat (%) increased (P < 0.05), mean milk protein tended to increase, and the mean milk yield and FCM tended to be enhanced. Plasma T3, T4 tended to decline whereas insulin enhanced (P < 0.01) significantly in LT herd (n = 49).

CONCLUSIONLactonin helps heat-stressed cow to maintain a more normal metabolism in hot summer. This positive effect of Lactonin on cow performance is associated with Lactonin-dependent alteration of plasma insulin, T3 and T4.

Animals ; Cattle ; Cysteamine ; pharmacology ; Female ; Hot Temperature ; Lactation ; Milk ; secretion ; Seasons

BACKGROUND:Large numbers of experimental data have confirmed that bone marrow mesenchymal stem cel s have a positive therapeutic effect on cerebral ischemia-reperfusion injury, but there are few reports about intravenous administration of bone marrow mesenchymal stem cel conditioned medium in the treatment of stroke.
OBJECTIVE:To investigate the effects of the conditioned medium of rat bone marrow mesenchymal stem cel s on the recovery of neurological function in rats after cerebral ischemia-reperfusion injury.
METHODS:The bone marrow mesenchymal stem cel s were isolated from rat bone marrow. When cel s at passage 2 or 3 reached 90%confluence, the original culture medium was removed. Then the cel s were cultured in serum-free DMEM for 18 hours. After that, the culture solution was col ected as the conditioned medium of rat bone marrow mesenchymal stem cel s. Adult rats were subjected to 2 hours of right middle cerebral artery occlusion. Ischemia-reperfusion injury rats were randomly assigned to three groups:control group, simple culture medium group and conditioned medium group, and respectively given injection of normal saline, DMEM, conditioned medium (10 mL/kg) via the tail vein at 2, 24, 48 hours after operation.
RESULTS AND CONCLUSION:There was no difference in the behavioral tests among the three groups at postoperative 2 hours (P>0.05). Compared with the control and simple culture medium group, neurological impairment was significantly improved in the conditioned medium group at postoperative 1, 3, 5 days (P<0.05), but there was no significant difference between the control and simple culture medium groups. At postoperative 5 days, brain edema was significantly eased in the conditioned medium group in comparison to the control and simple culture medium groups (P<0.05), and there was also no difference between the latter two groups (P>0.05). These results suggest that rat bone marrow mesenchymal stem cel s-conditioned medium via intravenous administration can significantly ease brain edema and improve the neurologic function after cerebral ischemia-reperfusion injury.