• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.9
• /
• pp.1374-1388
• /
• 2007

Three experiments were conducted to investigate the hypothesis that cows grazing on pasture produce the highest proportion of c-9 t-11 CLA in milk fat and no further increase can be achieved through supplementation of diets rich in linoleic acid, such as full-fat extruded soybeans or soybean oil. In experiment 1, 18 lactating Holstein cows were used in a randomized complete block design with measurements made from wk 4 to 6 of the experiment. In experiment 2, three cannulated lactating Holstein cows were used in a $3{\times}3$ Latin square design. Each period was 4 wk with measurements made in the final wk of each period. Cows in both experiments were assigned at random to treatments: a, conventional total mixed ration (TMR); b, pasture (PS); or c, PS supplemented with 2.5 kg/cow per day of full-fat extruded soybeans (PES). In both experiments, feed intake, milk yield, milk composition, and fatty acid profile of milk and blood serum were measured, along with fatty acid composition of bacteria harvested from rumen digesta in experiment 2. In experiment 3, 10 cows which had continuously grazed a pasture for six weeks were assigned to two groups, with one group (n = 5) on pasture diet alone (PS) and the other group (n = 5) supplemented with 452 g of soy oil/cow per day for 7 d (OIL). In experiment 1, cows in PS treatment produced 350% more c-9, t-11 CLA compared with cows in TMR treatment (1.70 vs. 0.5% of fat), with no further increase for cows in PES treatment (1.50% of fat). Serum c-9, t-11 CLA increased by 233% in PS treatment compared with TMR treatment (0.21 vs. 0.09% of fat) with no further increase for cows in PES treatment (0.18% of fat). In experiment 2, cows in PS treatment produced 300% more c-9 t-11 CLA in their milk fat compared with cows in TMR treatment (1.77 vs. 0.59% of fat), but no further increase for cows in PES treatment (1.84% of fat) was observed. Serum c-9, t-11 CLA increased by 250% for cows in PS treatment compared with cows in TMR treatment (0.27 vs. 0.11% of fat), with no further increase for cows in PES treatment (0.31% of fat). The c-9, t-11 CLA content of ruminal bacteria for cows in PS treatment was 200% or more of TMR treatment, but no further increase in bacterial c-9, t-11 CLA for cows in PES treatment was observed. Supplementation of soy oil in experiment 3 also did not increase the c-9 t-11 CLA content of milk fat compared with cows fed a full pasture diet (1.60 vs. 1.54% of fat). Based on these findings, it was concluded that supplementing with feeds rich in linoleic acid, such as full-fat extruded soybeans or an equivalent amount of soy oil, to cows grazing perennial ryegrass pasture may not increase milk fat c-9 t-11 CLA contents.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.4
• /
• pp.500-508
• /
• 2016

This study was conducted to investigate the effects of Momordica charantia saponin (MCS) on ruminal fermentation of maize stover and abundance of selected microbial populations in vitro. Five levels of MCS supplements (0, 0.01, 0.06, 0.30, 0.60 mg/mL) were tested. The pH, $NH_3-N$, and volatile fatty acid were measured at 6, 24, 48 h of in vitro mixed incubation fluids, whilst the selected microbial populations were determined at 6 and 24 h. The high dose of MCS increased the initial fractional rate of degradation at t-value = 0 ($FRD_0$) and the fractional rate of gas production (k), but decreased the theoretical maximum of gas production ($V_F$) and the half-life ($t_{0.5}$) compared with the control. The $NH_3-N$ concentration reached the lowest concentration with 0.01 mg MCS/mL at 6 h. The MSC inclusion increased (p<0.001) the molar proportion of butyrate, isovalerate at 24 h and 48 h, and the molar proportion of acetate at 24 h, but then decreased (p<0.05) them at 48 h. The molar proportion of valerate was increased (p<0.05) at 24 h. The acetate to propionate ratio (A/P; linear, p<0.01) was increased at 24 h, but reached the least value at the level of 0.30 mg/mL MCS. The MCS inclusion decreased (p<0.05) the molar proportion of propionate at 24 h and then increased it at 48 h. The concentration of total volatile fatty acid was decreased (p<0.001) at 24 h, but reached the greatest concentration at the level of 0.01 mg/mL and the least concentration at the level of 0.60 mg/mL. The relative abundance of Ruminococcus albus was increased at 6 h and 24 h, and the relative abundance of Fibrobacter succinogenes was the lowest (p<0.05) at 0.60 mg/mL at 6 h and 24 h. The relative abundance of Butyrivibrio fibrisolvens and fungus reached the greatest value (p<0.05) at low doses of MCS inclusion and the least value (p<0.05) at 0.60 mg/mL at 24 h. The present results demonstrates that a high level of MCS quickly inhibits in vitro fermentation of maize stover, while MCS at low doses has the ability to modulate the ruminal fermentation pattern by regulating the number of functional rumen microbes including cellulolytic bacteria and fungi populations, and may have potential as a feed additive applied in the diets of ruminants.

• Asian-Australasian Journal of Animal Sciences
• /
• v.11 no.5
• /
• pp.510-521
• /
• 1998

The effects of two types of protein, soybean meal (SBM) and fish meal (FM); and two types of energy supplements, corn flour (CF) and paper pulp (PP), on intake of guinea grass (Panicum maximum), fibre digestion and microbial activities in four Merino rams with an average weight of $54.4{\pm}4.5kg$ were studied. Each animal was fitted with a ruminal cannula and a duodenal cannula at the proximal position. The animals were fed twice daily with chopped guinea grass (5 cm) ad libitum and one of the four dietary supplements: 170 g FM+268 g PP; 170 g FM+268 g CF; 200 g SBM+200 g PP or 200 g SBM+200 g CF. All the supplements were mixed with 100 g molasses. In sacco and in vivo digestibilities, digesta flow rates, fermentation and microbial population were studied in a $4{\times}4$ Latin square design with a $2{\times}2$ factorial arrangement of dietary treatments. The effects of energy or protein sources were not significant on grass intake of sheep. The potential degradabilities of NDF and ADF were not significantly affected by any of the supplements. However, the energy and protein sources had significant efects on disappearance rate of NDF and ADF. The disappearance rate of both NDF and ADF were significantly (p < 0.05) higher in animals fed PP when compared to animals fed CF. Animals fed FM also showed significantly (p < 0.03) higher disappearance rate of ADF than those fed SBM. Animals fed PP showed better digestion in the rumen and total tract. Total flow of NDF and ADF through the duodenum was not significantly affected by the various supplements. The mean rumen pH values (5.8-6.1) were not significantly different among the four different diets. The concentration of rumen ammonia was significantly (p < 0.0001) higher in animals fed SBM (235-266.4 mg N/L) supplement than in animals fed FM (174.9-179.7 mg N/L), while total VFA concentration was not significantly affected by both energy and protein supplements. Mean values of total VFA ranged from 72.5-82.3 mM. Molar proportions of acetate, propionate and butyrate were typical of a roughage type fermentation. Molar proportion of acetate was significantly (p < 0.0001) higher in sheep fed PP when compared to sheep fed CF. Animals fed FM had higher total viable bacterial counts, while animals fed CF showed higher protozoal numbers. Proportions of cellulolytic bacteria were only slightly higher in animals fed SBM or PP.

• Journal of Animal Science and Technology
• /
• v.65 no.1
• /
• pp.132-148
• /
• 2023

Ruminants are the main contributors to methane (CH₄), a greenhouse gas emitted by livestock, which leads to global warming. In addition, animals experience heat stress (HS) when exposed to high ambient temperatures. Organic trace minerals are commonly used to prevent the adverse effects of HS in ruminants; however, little is known about the role of these minerals in reducing enteric methane emissions. Hence, this study aimed to investigate the influence of dietary organic trace minerals on rumen fermentation characteristics, enteric methane emissions, and the composition of rumen bacteria and methanogens in heat-stressed dairy steers. Holstein (n=3) and Jersey (n=3) steers were kept separately within a 3×3 Latin square design, and the animals were exposed to HS conditions (Temperature-Humidity Index [THI], 82.79 ± 1.10). For each experiment, the treatments included a Control (Con) consisting of only basal total mixed rations (TMR), National Research Council (NRC) recommended mineral supplementation group (NM; TMR + [Se 0.1 ppm + Zn 30 ppm + Cu 10 ppm]/kg dry matter), and higher concentration of mineral supplementation group (HM; basal TMR + [Se 3.5 ppm + Zn 350 ppm + Cu 28 ppm]/kg dry matter). Higher concentrations of trace mineral supplementation had no influence on methane emissions and rumen bacterial and methanogen communities regardless of breed (p > 0.05). Holstein steers had higher ruminal pH and lower total volatile fatty acid (VFA) concentrations than Jersey steers (p < 0.05). Methane production (g/d) and yield (g/kg dry matter intake) were higher in Jersey steers than in Holstein steers (p < 0.05). The relative abundances of Methanosarcina and Methanobrevibacter olleyae were significantly higher in Holstein steers than in Jersey steers (p < 0.05). Overall, dietary organic trace minerals have no influence on enteric methane emissions in heat-stressed dairy steers; however, breed can influence it through selective alteration of the rumen methanogen community.

• Journal of Animal Environmental Science
• /
• v.17 no.sup
• /
• pp.7-20
• /
• 2011

This study was conducted to analyze the mixing ratio of raw feed materials for the methane mitigation and also to identify the minimum rearing density for improving the productivity of beef calves as eco-friendly fodder. Raw materials used in this study for the formulation of feed for methane reduction were crushed corn and alfalfa along with other 21 species. In addition, to investigate the appropriate rearing density, 12 Hanwoo calves with average weight of 150 kg was selected and experiment was conducted for four months. Methane gas emission (Bo) is about 3-4 times less in TMR 4 compared to TMR 1, 2 and 3. Feed price calculated for TMR 4 ration was also affordable. In addition, all TMRs showed a normal ruminal pH. Disappearance rate was observed to be lower in TMR 4 as compared to TMR 1, 2 and 3, but methane production decreased by 24 to 37%. The result showed improved total body weight, average daily gain and feed conversion ratio in rearing low-density ($18m^2/head$), and general treatment ($9m^2/head$) compared to overcrowding treatment ($6m^2/head$). In addition, blood components (total protein, glucose, AST, ALT and GGT factors) involved in health and disease treatments and health-related nutrition metabolism are lower in the low-density and general treatment compared to the high density treatment. Postural development (development of body size) i.e., weight, height and width significantly increased in the low and general density treatment compared to high density treatment. Especially excellent improvement was observed in low-density treatment than the general treatment. Moisture content, colonic bacteria and coccidium are higher in low and high density treatments than in the general treatment. The adequacy for beef rearing density is considered to be more desirable in an area more than $6m^2/head$. In conclusion, present study suggests that possibility of methane reduction through adjusting mixed feed ration. Also, rearing density is also an important factor in the growth and development of beef calves.