Effects of treating rice straw with urea or urea and calcium hydroxide upon intake, digestibility, rumen fermentation and milk yield of dairy cows

Three, multiparous Holstein crossbred dairy cows with initial body weight of 385 ± 19 kg were randomly allocated to 3 treatments of rice straw (T1 = untreated rice straw; T2 = 5.5% urea-treated rice straw (5 g urea in 100 ml water to 100 g air-dry (91% DM) straw); T3 = 2.2% urea + 2.2% calcium hydroxide treated rice straw (2.0 g urea and 2.0 g Ca(OH)₂ in 100 ml to 100 g air-dry (91% DM) straw) according to a 3 × 3 Latin square design. Each period lasted for 21 days in which feed, feces and rumen fluid were collected during the last 7 days for chemical analyses. The findings revealed significant improvements in dry matter intake and digestibility by using 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw. Ruminal pH and NH₃-N were found higher (P < 0.05) as compared with urea-treated rice straw fed group, while blood urea nitrogen and milk urea nitrogen were in normal ranges. Volatile fatty acid concentrations especially those of acetic acid were decreased (P < 0.05) and those of propionic acid were increased (P < 0.05), thus acetic acid:propionic acid was subsequently lowered (P < 0.05) in cows fed with 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw, respectively. Moreover, ruminal viable and cellulolytic bacterial counts were enhanced by urea and calcium hydroxide treatments. Milk protein and fat concentrations were additionally increased by respective treatments while 3.5% fat-corrected milk was highest; ranking from 2.2% urea + 2.2% calcium hydroxide treated rice straw, 5.5% urea-treated rice straw and urea-treated rice straw fed groups. Based on this study, implications could be made that using 2.2% urea + 2.2% calcium hydroxide treated rice straw for straw treatment could be an alternative treatment to 5.5% urea treatment with regards to its effectiveness and treatment cost for lactating dairy cows.     

Comparison of silage and hay of dwarf Napier grass (<Emphasis Type="Italic">Pennisetum purpureum</Emphasis>) fed to Thai native beef bulls

Both quantity and quality of forages are important in dry season feeding. Eight Thai native beef bulls were arranged in a Completely randomized design to evaluate dwarf Napier namely Sweet grass (Pennisetum purpureum cv. Mahasarakham) preserved as silage or hay on feed intake, digestibility, and rumen fermentation. The animals were fed with forage ad libitum supplemented with concentrate mixture at 1.0% of BW for 21 days; data were collected during the last 7 days. The results showed that there were differences (P?<?0.05) between treatments in dry matter (DM) intake, DM digestibility, and ruminal pH, in which hay feeding gave enhanced feed intake and more favorable ruminal pH. Nevertheless, mean ruminal ammonia nitrogen, total volatile fatty acids (TVFAs), proportion of VFAs, bacterial and protozoal population, and blood urea nitrogen were similar (P?>?0.05) in animals fed silage and hay. Sweet grass is better preserved as hay rather than silage.     

Effects of urea treatment of straw and dietary level of vegetable oil on lactating dairy cows

Four crossbreds (75% Holstein Friesian) lactating dairy cows were used to evaluate the effects of sunflower oil (SFO) levels and roughage source on feed intake, nutrient digestibility, ruminal fermentation, milk yield, and milk composition. Four milking cows with average liveweight of 410 ± 25 kg and 18 ± 11 days in milk were randomly assigned according to a 4 × 4 Latin square design, in a 2 × 2 factorial arrangement, with SFO levels (3% or 6%) in the concentrate and the roughage source [rice straw (RS) or urea-treated RS (UTRS)] being the main factors. Four dietary treatments as (1) 3% SFO + RS, (2) 6% SFO + RS, (3) 3% SFO + UTRS, and (4) 6% SFO + UTRS were offered ad libitum total mixed ration, with a concentrate/roughage ratio of 60:40. The results were found that UTRS as a roughage source significantly increased feed intake, digestibility, concentration of acetic acid in rumen fluid, rumen ammonia–nitrogen, blood–urea nitrogen, milk urea–nitrogen, and milk yield (3.5% fat-corrected milk) compared with cows fed on untreated RS. Supplementation of SFO at 3% in the concentrate-supplemented group having increased dry matter intake, milk fat percentage, and milk yield (3.5% fat-corrected milk) compared with 6% SFO supplementation. However, there were no interaction effects between level of SFO in the concentrate and roughage source in any of the factors studied.     

Dietary dragon fruit (Hylocereus undatus) peel powder improved in vitro rumen fermentation and gas production kinetics

Plant phytophenols especially condensed tannins (CT) and saponins (SP) have been demonstrated to impact on rumen fermentation. Dragon fruit (Hylocereus undatus) peel powder (DFPP) contains both CT and SP. The current study aimed to investigate the influence of DFPP and varying levels of concentrate and roughage ratios on gas production kinetics, nutrient degradability, and methane production “using in vitro gas production technique.” The dietary treatments were arranged according to a 3?×?5 Factorial arrangement in a completely randomized design. The two experimental factors consisted of the roughage to concentrate (R:C) ratio (100:0, 70:30, and 30:70) and the levels of DFPP supplementation (0, 1, 2, 3, and 4% of the substrate) on DM basis. The results revealed that the R:C ratio at 30:70 had the highest cumulative gas production when compared to other ratios (P?<?0.01). The in vitro true dry matter degradability at 12 and 24 h was affected by R:C ratio (P?<?0.01). Furthermore, volatile fatty acids (VFA) and propionate (C3) were significantly increased by the levels of DFPP, while acetate (C2) and C2:C3 ratios were decreased (P?<?0.05). The rumen protozoal population was significantly decreased by DFPP supplementation (P?<?0.05). Rumen methane production was significantly impacted by R:C ratios and decreased when the level of DFPP increased (P?<?0.01), while NH₃-N and ruminal pH were not influenced by the DFPP supplement. It could be summarized that supplementation of DFPP resulted in improved rumen fermentation kinetics and could be used as a dietary source to mitigate rumen methane production, hence reducing greenhouse gas production.