Effect of UV-B irradiated vitamin D enriched yeast supplementation on milk performance and blood chemical profiles in dairy cows.

OBJECTIVE: The objective was to evaluate the effects of UV-B irradiated vitamin D-enriched yeast supplementation on milk yield, milk composition, vitamin D in milk, milk fatty acids, blood chemistry, and 25(OH)D status in dairy cows. METHODS: Six Thai Friesian cows (milk production, 11.2±2.0 kg/d; body weight, 415.0±20.0 kg; and days in milk, 90.0±6.0) were allocated to each treatment in a 3×3 Latin square design, with three treatments and three periods. Each period of the Latin square lasted 49 days consisting of 14 days for diet adaptation and 35 days for sample collection. Dairy cows were randomly assigned to one of three treatments: i) feeding a basal diet without yeast (CON); ii) basal diet + 5 g of live yeast (75 IU/head/d of vitamin D2; LY); and iii) basal diet + 5 g of UV-B irradiated vitamin D enriched yeast (150,000 IU/head/d of vitamin D2; VDY). Feed intake and milk production were recorded daily, milk sample collection occurred on days 14 and 35 of each collection period, and blood plasma was collected on days 0, 7, 14, 21, 28, and 35 of each collection period. RESULTS: The results show that after a trial period of 14 and 35 days, the VDY group had significantly higher vitamin D content in milk than the LY and CON groups (376.41 vs 305.15, 302.14 ng/L and 413.46 vs 306.76, 301.12 ng/L, respectively). At days 7, 14, 21, 28, and 35 of the experiment, cows fed the VDY group had significantly higher 25(OH)D2 status in blood than the CON and LY groups (51.07 vs 47.16, 48.05 ng/mL; 54.96 vs 45.43, 46.91 ng/mL; 56.16 vs 46.87, 47.16 ng/mL; 60.67 vs 44.39, 46.17 ng/mL and 63.91 vs 45.88, 46.88 ng/mL), respectively. CONCLUSION: In conclusion, UV-B irradiated vitamin D-enriched yeast supplementation could improve vitamin D content in the milk and 25(OH)D status in dairy cows during the lactation period.

Replacement of soybean meal by red yeast fermented tofu waste on feed intake, growth performance, carcass characteristics, and meat quality in Thai Brahman crossbred beef cattle.

This study aimed to determine the effect of replacing soybean meal (SBM) by red yeast fermented tofu waste (RYFTO) on feed intake, growth performance, carcass characteristics, and meat quality in Brahman crossbred beef cattle. A total of 12 cattle (1.5-2 years old and 275.0 ± 6.1 kg of initial body weight) were randomly allotted to three dietary treatments in completely randomized design. There were three dietary treatments as following: Control (SBM), 50%replacing SBM by red yeast fermented tofu waste (RYFTO50), and 100% replacing SBM by red yeast fermented tofu waste (RYFTO100) in concentrate diet raised for 60 days. Rice straw was used as roughage source and fed ad libitum. The results found that cattle received the diet with replacing SBM by RYFTO both RYFTO50 and RYFTO100 group affect roughage intake, total dry matter intake, and ADG (P < 0.05) except the digestibility and FCR (P > 0.05). The feed cost of roughage, concentrate, and total feed cost were lowest in RYFTO100 group when compared to the control (P < 0.05). Blood urea nitrogen was deducted when cattle received RYFTO100 when compared to the control and RYFTO50 (P < 0.05). However, the carcass characteristics and meat quality were similar among treatments (P > 0.05). In conclusion, the 100% replacing SBM by RYFTO in concentrate diet affect roughage intake and ADG without negative effect on concentrate intakes, digestibility, carcasses and meat quality. Therefore, RYFTO could be used as a protein source for partial replacement of SBM in the, concentrate diet at 50% which can lower feed cost. This study suggested that the further study should be conducted for longer period to gain the benefits of carotene in red yeast on carcass and meat quality.

Improved reproductive performance achieved in tropical dairy cows by dietary beta-carotene supplementation.

Dairy farming in tropical climates is challenging as heat stress can impair reproduction in cows. Previous studies have demonstrated the beneficial effects of beta-carotene supplementation on bovine reproductive performance. This study was performed in Thailand, where the temperature-humidity index (THI) during the experimental periods was measured to range from 78.4 to 86.1. Lactating Holstein cows classified as repeat breeders (previous artificial insemination [AI] failures) were randomly assigned into two treatments, control treatment (T1; received placebo, n = 200) and test treatment (T2; received 400 mg/h/day of beta-carotene, n = 200). All cows were subjected to a protocol for synchronization of ovulation and timed artificial insemination (TAI). The day of the 1st ovulation synchronized protocol was defined as day 0, and the total experimental period was 160 days. Daily placebo or beta-carotene supplements were given orally on day 0 and each subsequent day of the experiment. Diagnosis of pregnancy was performed using ultrasound on day 30 after insemination. Non-pregnant cows were subjected to further ovulation synchronizations (maximum of four) and TAI over a period of 160 days. Milk samples were collected every ten days throughout the experiment. The samples were analyzed for beta-carotene concentration, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. The pregnancies per AI of the cows in T2 were significantly greater than that of T1 from the 2nd to 4th TAI. During the entire experimental period, the pregnancies in T2 were significantly greater than that of T1. Cox's proportional hazards regression model data indicated a 44% greater probability of pregnancy for cows receiving beta-carotene. The concentrations of milk beta-carotene in T2 were significantly greater than T1 from the 2nd to 4th TAI. Significantly greater SOD and GPx activities were observed in T2 than T1, suggesting a reduction of oxidative stress in cows treated with beta-carotene. Dietary supplementation with beta-carotene thus improves the reproductive performance of repeat breeders exposed to heat stress, possibly by reducing oxidative stress.