No abstract

Multiparous early lactation Holstein cows (n = 16) were used in a randomized complete block design to determine the effects of feeding fatty acid calcium and the interaction of forage quality on production performance and biochemical indexes in early lactation cow. Treatments were as follows: (i) feeding low-quality forage without supplying fatty acid calcium (Diet A), (ii) feeding low-quality forage with supplying 400 g fatty acid calcium (Diet B), (iii) feeding high-quality forage without supplying fatty acid calcium (Diet C) and (iv) feeding high-quality forage with supplying 400 g fatty acid calcium. This experiment consisted 30 days. The milk and blood samples were collected in the last day of the trail. Intakes were recorded in the last 2 days of the trail. Supplementation of fatty acid calcium decreased significantly dry matter intake (DMI) (p < 0.01). Addition fatty acid calcium decreased milk protein percentage (p < 0.01) and milk SNF percentage (p < 0.01), but increased MUN (p < 0.05). Supplemented fatty acid decreased concentration of blood BHBA (p < 0.05), but increased TG, NEFA, glucagon, GLP-1, CCK, leptin, ApoA-IV, serotonin and MSH concentration in blood, the CCK concentration and feed intake showed a significant negative correlation (p < 0.05).

An understanding of physiological damage and population development caused by uncomfortable temperature plays an important role in pest control. In order to clarify the adaptability of different temperatures and physiological response mechanism of B. dorsalis, we focused on the adaptation ability of this pest to environmental stress from physiological and ecological viewpoints. In this study, we explored the relationship between population parameters and glucose, glycogen, trehalose, and trehalose-6-phosphate synthase responses to high and low temperatures. Compared with the control group, temperature stress delayed the development duration of all stages, and the survival rates and longevity decreased gradually as temperature decreased to 0 °C and increased to 36 °C. Furthermore, with low temperature decrease from 10 °C to 0 °C, the average fecundity per female increased at 10 °C but decreased later. Reproduction of the species was negatively affected during high-temperature stresses, reaching the lowest value at 36 °C. In addition to significantly affecting biological characteristics, temperature stress influenced physiological changes of B. dorsalis in cold and heat tolerance. When temperature deviated significantly from the norm, the levels of substances associated with temperature resistance were altered: glucose, trehalose, and TPS levels increased, but glycogen levels decreased. These results suggest that temperature stresses exert a detrimental effect on the populations’ survival, but the metabolism of trehalose and glycogen may enhance the pest’s temperature resistance.

The present study investigated the effects of the supplemental dietary energy source on early lactating cows in a positive energy balance. Cows in the control group were fed a basal total mixed ration containing high-quality hay as forage, and the dietary concentrate to forage ratio was 45:65. The corn supplementation resulted in a significant decrease in the milk fat content (P < 0.05) and a low milk fat yield (P = 0.15), whereas the fat supplementation resulted in a decreasing trend of the milk protein and lactose content (P ≤ 0.1). Additionally, the corn supplementation significantly decreased the serum 5-hydroxytryptamine level (P < 0.05). The results support the proposal that the source of supplemental dietary energy has varying effects on feed intake, lactation performance, and the intermediate metabolism of early lactating cows in a positive energy balance. 5-Hydroxytryptamine secretion may be associated with the varying effects of the source of supplemental dietary energy.