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Although the rumen microbiome has been reported to synthesize a rich source of symbiotic enzymes (exocellulase, endocellulase, hemicellulase and cellobiase), the digestion of tropical C4 grasses and browses by ruminants is still limited. Therefore, this study aimed to unveil potential fibrolytic microbial ecosystems from giraffe, kudu, impala and consortia (A1 [giraffe + kudu], A2 [giraffe + impala], A3 [kudu + impala], and A4 [giraffe + kudu + impala]) browsing tanniferous plants, which can be used to improve forage utilization in domesticated goat. Crude protein enzyme extracts (CPZ) from fresh faecal samples were precipitated by 60% ammonium sulphate and assayed for exocellulase, endocellulase and hemicellulase by incubating with crystalline cellulose, carboxymethyl cellulose and xylan at 38 °C with optimum pH of 5.5 to 6.5 for 1, 2, and 48 h, respectively. Enzyme specific activities were defined as μg of reducing sugar/mg CPZ. In vitro fermentation study was done by transferring 33 mL of fresh faecal inoculum into 67 mL of salivary buffer containing 1 g Acacia sieberiana and incubating for 72 h at 38 °C. Apparent degradability (APDeg), true degradability (TD), neutral detergent fibre degradability (NDFdeg), acid detergent fibre degradability (ADFdeg), microbial yield (MY), metabolizable energy (ME) and total gas emitted (Gas) were measured. Exocellulase activities were higher (P

To reveal the seasonal dynamics of herbage intake, diet composition and digestibility and clarify the relationship of those with herbage nutrient and botanical composition of grazing sheep in Zhenglan Banner of Inner Mongolia, the n-alkane technique was used to test in sheep grazed during June, August and December. The results showed that the sheep mainly ate Fringed sagebrush, Stipa krylovii and Carex in proportions of 33.5, 17.9 and 21.2%, respectively, in spring. In summer, the sheep consumed cleistogenes, Potentilla tanacetifolia, Thyme, etc; the intake of Fringed sagebrush, Carex and Stipa declined. In winter, Fringed sagebrush accounted for 50.1% of herbage intake, and the intakes of Cleistogenes and Stipa krylovii increased to 15.3 and 18.4%, respectively. Herbage intake by the sheep in spring was 1.8 kg DM/d, and digestibility was 71.4%. Herbage intake and digestibility decreased slightly to 1.7 kg DM/d and 68.4% during the summer, respectively and decreased significantly to 1.2 kg DM/d and 36.4% in winter. There were significant correlations between diet composition and CP content in winter, diet composition and botanical composition in summer. A highly positive correlation between herbage intake and digestibility was observed in grazing sheep.

As a new type of methane control agent, natural plant extract has been widely studied in recent years, but in vivo studies are few. This study was to investigate the effects of the dietary supplementation of 2 different polyphenols on the methane (CH4) emission and digestion metabolism in sheep. Ten healthy crossbred sheep (Dorper ♂ × small-tailed Han ♀; BW 60.0 ± 1.73 kg) were used in a change-over design. The sheep were fed the following 3 diets in the present study: the basal diet (CON) with no supplementation; the basal diet supplemented with 2 g mulberry leaf flavonoid (MLF) per day per sheep; the basal diet supplemented with 0.25 g resveratrol (RES) per day per sheep. Both MLF and RES reduced CH4 emission scaled to metabolic weight per kilogram of DMI and CO2 output scaled to metabolic weight, but the effect of RES was significant (P 0.05). In conclusion, MLF and RES can improve the digestibility of nutrients, the utilization of nutrients and energy, and reduce CH4 emission, but they are not conducive to nitrogen retention.

The utilization of urea in camels has beneficial and negative effects. The aims of this study were to investigate the effects of different levels of urea supplementation on nutrients intake, digestibility, growth performance, feed efficiency and economics in growing camels fed roughage based complete pellet diets. In the present study, eighteen growing camels with an average live body weight of 306.17 ± 2.05 kg were randomly assigned in three treatments: T1 = roughage complete pellet diet without urea, T2 = T1 plus 1% urea, and T3 = T1 plus 2% urea. The results showed that the urea supplementation significantly affected average daily feed and nutrient intake of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) (P 0.05). Similarly, digestion coefficient of DM, CP, ether extract (EE), crude fiber (CF) and ADF was influenced by increasing urea level (P 0.05). The intake of digestive nutrients was similar among all treatment groups. Total body live weight gain and average daily gain were significantly higher in urea supplemented groups (P

Studies have shown that supplementing ruminant diets with vegetable oils modulated the rumen biohydrogenation and increased polyunsaturated fatty acid in their products. These positive values are often accompanied by a marginal loss of supplemented unsaturated fatty acids and rise in the concentrations of saturated fatty acids. This study were carried out mainly to investigate the effect of supplementing diets with sunflower oil, olive oil with or without monensin on the production and accumulation of vaccenic acid (VA) in continuous culture fermenters as a long term in vitro rumen simulation technique. Eight dual-flow continuous culture fermenters were used in an 8 replication experiment lasted 10 days each (first 7 days for adaptation and last 3 days for samples collection). Supplementing diets with plant oils and monensin in the present experiment increased VA and conjugated linoleic acids (P > 0.05) in ruminal cultures. The results suggest that supplementing diets with both olive oil and sunflower oil and monensin increased VA accumulation compared to plant oils supplemented alone without affecting the rumen dry matter and organic matter digestibility.

This study was conducted to investigate the effect of weaning age on growth performance, nutrient digestion and metabolism, and serological indicators, and to obtain an optimal weaning age in Hu lambs. Forty-eight newborn Hu lambs (birth weight, 2.53 ± 0.14 kg) were randomly divided into 4 groups. The lambs in control group (ER) suckled their dams. The lambs in other three experimental groups were weaned on milk replacer at 10, 20, and 30 days of age (EW10, EW20, and EW30 groups), respectively. The results were as follows: 1) lambs in EW10 and EW30 groups had a lower (P 0.05) among groups; however, the apparent digestibility and deposition of calcium in early weaned lambs were lower (P

The experiment was conducted to evaluate hormonal involvement in the adipose metabolism and lactation between high and low producing dairy cows in a hot environment. Forty Holstein healthy cows with a similar parity were used and assigned into high producing group (average production 41.44 ± 2.25 kg/d) and low producing group (average production 29.92 ± 1.02 kg/d) with 20 cows in each group. Blood samples were collected from caudal vein to determine the difference of hormones related to adipose metabolism and lactation. The highest, lowest, and average temperature humidity index (THI), recorded as 84.02, 79.35 and 81.89, respectively, indicated that cows were at the state of high heat stress. No significant differences between high and low producing groups were observed in the levels of nonestesterified fatty acid (NEFA), β-hydroxybutyrate (β-OHB), total cholesterol (TCHO), and insulin (INS) (P > 0.05). However, the very low density lipoprotein (VLDL), apolipoprotein B100 (apoB-100), high-density lipoprotein (HDL-C) and estrogen (E2) concentrations in high producing group were significantly higher than those of low producing group (P 0.05), whereas high producing group had a rise in the insulin-like growth factor-1 (IGF-1) level compared with low producing group (P

Enteric methane emission is not only a source of energy loss in ruminants, but also a potent contributor to greenhouse gas production. To identify the nature and timing of interventions to reduce methane emissions requires knowledge of temporal kinetics of methane emissions during animal husbandry. Accordingly, a mathematical model was developed to investigate the pattern of enteric methane emissions after feeding in dairy cows. The model facilitated estimation of total enteric methane emissions (V, g) produced by the residual substrate (V1, g) and newly ingested feed (V2, g). The model was fitted to the 10 h methane emission patterns after morning feeding of 16 non-lactating dairy cows with various body weights (BW), and the obtained parameters were used to predict the kinetics of 24 h methane emission for each animal. The rate of methane emission (g/h) reached a maximum within 1 to 2 h after feeding, followed by a gradual post-prandial decline to a basal value before the next feeding. The model satisfactorily fitted curves for each cow according to the criterion of goodness-of-fit, and provided biological descriptions for fluctuations in methane emissions based on basal V1 and feeding V2 in response to the changes in BW and dry matter intake (DMI) of different dairy cows. The basal V1 and feeding V2 are probably maintained by slow- and readily-degradable substrates, respectively. The former contributed at least 0.6 of methane production. In summary, the model provides a means to separate basal V1 and feeding V2 within V, and can be used to predict 24 h emission from a single feeding period.

This study investigated the effects of protein sources for milk replacers on growth performance and serum biochemical indexes of suckling calves. Fifty Chinese Holstein bull calves with similar BW and age were randomly allocated to 5 groups (1 control and 4 treatments) of 10 calves in each group. Five types of milk replacers were designed to have the same level of energy and protein. The protein source for milk replacers of the control group was full milk protein (MP). The protein source of milk replacers of the 4 treatment groups was composed of MP and one vegetable protein (VP) (30 and 70% of total protein). The 4 types of VP were soybean protein concentrate (SP), hydrolyzed wheat protein (WP), peanut protein concentrate (PP), and rice protein isolate (RP). Results of the experiment showed: 1) there was no significant difference on average daily gain (ADG) and feed:gain ratio (F:G) among the MP, SP and RP groups (P > 0.05), whereas the ADG and F:G of the WP and PP groups were significantly lower compared with the MP group (P 0.05). Thereby the 4 VP milk replacers had no adverse effects on body size of calves; 3) all groups showed no significant difference in the serum contents of urea nitrogen, total protein, albumin, globulin, β-hydroxybutyrate, growth hormone, insulin-like growth factor-1, and the ratio of albumin to globulin (A:G) (P > 0.05). In conclusion, SP or RP (accounts for 70% of the total protein) as calf milk replacers could substitute MP, whereas wheat gluten and PP had a significant adverse effect on growth performance in this experiment.