Chinese Wildrye Research Articles

Replacing alfalfa hay with industrial hemp ethanol extraction byproduct and Chinese wildrye hay: Effects on lactation performance, plasma metabolites, and bacterial communities in Holstein cows.

This trial was designed to investigate the effects of industrial hemp ethanol extraction byproduct (IHEEB) and Chinese wildrye hay (CWH) replacement of alfalfa hay (AH) on digestibility, and lactation performance, plasma metabolites, ruminal fermentation, and bacterial communities in Holstein dairy cows. Nine healthy multiparous Holstein cows (parity = 3) with similar body weights (584 ± 12.3 kg), days in milk (108 ± 11.4), and milk yields (30 ± 1.93 kg; all mean ± standard deviation) were used in a replicated 3 × 3 Latin square design with 3 periods of 21 d. During each period, each group consumed 1 of 3 diets: (1) 0% IHEEB (0IHEEB); (2) 6.0% IHEEB and 1.7% Chinese wildrye hay (6IHEEB); (3) 10.8% IHEEB and 4.3% Chinese wildrye hay (11IHEEB). The diets in each group were isocaloric and isonitrogenous, with similar contents of concentrate and silage but different ratios of IHEEB and CWH to replace AH. The results showed that increasing the substitute did not affect the total-tract apparent nutrient digestibility. There was no difference in lactation performance of dairy cows fed the three diets, except for the cows' somatic cell count (SCC), which decreased with the increase in the amount of the substitute. Cannabidiol and tetrahydrocannabinol were not detected in milk samples of dairy cows in the different treatment groups. 6IHEEB and 11IHEEB-fed cows showed a linear decrease in total volatile fatty acids (VFA) and butyrate compared to the 0IHEEB cows. Plasma IL-1β content quadratically decreased with feeding IHEEB and CWH, and other blood parameters were unaffected. The rumen fluid's relative abundances of Bacteroidota, Fibrobacterota, and Prevotellaceae quadratically increased, while Firmicutes tended to decrease quadratically as the substitution increased. Feeding IHEEB and CWH linearly increased the relative abundances of Firmicutes, Lachnospiraceae, Monoglobaceae, and Butyricicoccaceae in the feces. As the substitution increased, the cost of dairy farming was reduced. In summary, substituting AH with IHEEB and CWH in diets did not affect the total-tract apparent nutrient digestibility, improved milk composition, and plasma immune indices. It changed the bacterial composition in rumen fluid and feces and improved dairy farming benefits.

Gossypol Exhibited Higher Detrimental Effect on Ruminal Fermentation Characteristics of Low-Forage in Comparison with High-Forage Mixed Feeds.

Gossypol is a key anti-nutritional factor which limits the feeding application of cottonseed by-products in animal production. A 2 × 4 factorial in vitro experiment was conducted to determine the effect of gossypol addition levels of 0, 0.25, 0.5, and 0.75 mg/g on ruminal fermentation of a high-forage feed (HF, Chinese wildrye hay/corn meal = 3:2) in comparison with a low-forage feed (LF, Chinese wildrye hay/corn meal = 2:3). After 48 h of incubation, in vitro dry matter disappearance was greater in the LF than the HF group, while the cumulative gas production and asymptotic gas production were greater in the HF than the LF group (p < 0.05). Regardless of whatever ration type was incubated, the increasing gossypol addition did not alter in vitro dry matter disappearance. The asymptotic gas production, cumulative gas production, molar percentage of CO2 and H2 in fermentation gases, and microbial protein in cultural fluids decreased with the increase in the gossypol addition. Conversely, the gossypol addition increased the molar percentage of CH4, ammonia N, and total volatile fatty acid production. More than 95% of the gossypol addition disappeared after 48 h of in vitro incubation. Regardless of whatever ration type was incubated, the real-time PCR analysis showed that the gossypol addition decreased the populations of Fibrobacter succinogenes, Ruminococcus albus, Butyrivibrio fibrisolvens, Prevotella ruminicola, Selenomonas ruminantium, and fungi but increased Ruminococcus flavefaciens, protozoa, and total bacteria in culture fluids in comparison with the control (p < 0.01). Additionally, the tendency of a smaller population was observed for R. albus, B. fibrisolvens, and fungi with greater inclusion of gossypol, but a greater population was observed for F. succinogenes, R. flavefaciens, S. ruminantium, protozoa, and total bacteria. In summary, the present results suggest that rumen microorganisms indeed presented a high ability to degrade gossypol, but there was an obvious detrimental effect of the gossypol addition on rumen fermentation by decreasing microbial activity when the gossypol inclusion exceeded 0.5 mg/g, and such inhibitory effect was more pronounced in the low-forage than the high-forage group.

Comparison of Nutritive Values and in vitro Degradability of Steam Treated Rice Straw with Chinese Wild Rye and Alfalfa

Comparison of Nutritive Values and in vitro Degradability of Steam Treated Rice Straw with Chinese Wild Rye and Alfalfa

The Effect of Replacing Wildrye Hay with Mulberry Leaves on the Growth Performance, Blood Metabolites, and Carcass Characteristics of Sheep.

Simple SummaryIt is well known that mulberry leaves can be used in animal feed because of their high yield, rich protein content, and palatability. Our study found that partially replacing Chinese wildrye with mulberry leaves could improve meat quality without negatively affecting the growth performance, blood metabolites, and carcass characteristics of sheep. The study suggests that mulberry leaves partially substituted for conventional forage in the diet of sheep may be an effective strategy to alleviate the shortage of high-quality forage sources and to reduce feed costs.The objective of this study was to evaluate the effects of partially substituting for conventional forage, Chinese wildrye (CW), with mulberry leaves (ML) on the growth, digestion, ruminal fermentation, blood metabolites, and meat quality of sheep in a 65-day feedlot study. Thirty-two four-month-old male small-tailed Han sheep (25.15 ± 1.03 kg) were randomly assigned to one of four treatments. The dietary treatments consisted of four proportions of ML (0, 8, 24, and 32%) as a substitute for CW (designated as ML0, ML8, ML24, and ML32, respectively). Rumen digesta and blood samples were collected at day 63 of the trial. Carcass traits were assessed after slaughter at the end of performance period. The results from this study revealed no differences in average daily bodyweight gain (ADG), feed conversion ratio (FCR), and final body weight (FBW) among treatments. The apparent digestibility of dry matter (DM), organic matter (OM), and acid detergent fiber (ADF) was higher in the sheep fed with ML than in those fed CW. The ML24 treatment had a higher digestibility of crude protein (CP) and ether extract (EE). There were no differences (p = 0.13) in ruminal pH values among the treatments. However, there was more microbial protein (p < 0.01) in ML24 and ML32 treatments than the ML0 treatment. Ruminal concentrations of acetate and butyrate were significantly different among treatments, although no difference in concentrations of total volatile fatty acid were found. Additionally, no differences were detected for serum parameters except blood urea nitrogen (BUN). No differences were observed for carcass weight (p = 0.62), dressing percentage (p = 0.31) or longissimus dorsi muscle (LM) area (p = 0.94) among treatments. However, intramuscular fat was higher in the ML24 treatment than in the ML0 treatment. (p < 0.01). There were higher pH values of the 24-h longissimus dorsi in the ML24 treatment than in the ML0 treatment. In addition, the saturated fatty acid (SFA) content was lower (p < 0.01) and the monounsaturated fatty acid (MUFA) content higher (p < 0.01) in the ML24 treatment than in the ML0 treatment. In conclusion, the partially substitution of mulberry leaves for Chinese wildrye in the diet of sheep had a beneficial influence on the growth performance, blood metabolites and carcass characteristics. The inclusion of 24% (air dry basis) mulberry leaf hay in the ration of sheep is recommended based on these findings.

Diet Composition Affects Liver and Mammary Tissue Transcriptome in Primiparous Holstein Dairy Cows.

Simple SummaryCorn stover (CS) diets are still adopted by small dairy farms in China. Compared with mixed forage (MF) diets, feeding CS diet affects milk composition, digestibility, feed intake, ruminal fermentation, and lactation performance. Mammary gland and liver are two of the most important organs for lactation in cows. However, research related to the effect of CS diet on the metabolism of liver and mammary tissues of dairy cows is limited. Overall evaluation of the biological response of liver and mammary tissues of dairy cows to changes in CS diet compared with MF diet is essential. Thus, the objective of the present study was to evaluate the overall adaptation of liver and mammary tissue to a CS diet in mid-lactation primiparous dairy cows. Modest effect on the transcriptome of the liver and mammary tissue by the CS diet was observed. The analysis of the genes affected by CS indicated mammary gland responding to lower level of linoleate from the diet (lower in CS vs. MF) by activating the associated biosynthesis metabolism while the liver adaptively activated potassium transport to compensate for a lower K ingestion. The results of this study may facilitate the development of better feeding and management strategies and the increase of profitability of dairy farms.The objective of the present study was to evaluate the overall adaptations of liver and mammary tissue to a corn stover (CS) compared to a mixed forage (MF) diet in mid-lactation primiparous dairy cows. Twenty-four primiparous lactating Holstein cows were randomly allocated to 2 groups receiving either an alfalfa forage diet (MF, F:C = 60:40) with Chinese wildrye, alfalfa hay and corn silage as forage source or a corn stover forage diet (CS, F:C = 40:60). A subgroup of cows (n = 5/diet) was used for analysis of liver and mammary transcriptome using a 4 × 44K Bovine Agilent microarray chip. The results of functional annotation analysis showed that in liver CS vs. MF inhibited pathways related to lipid metabolism while induced the activity of the potassium channel. In mammary tissue, fatty acid metabolism was activated in CS vs. MF. In conclusion, the analysis of genes affected by CS vs. MF indicated mammary gland responding to lower level of linoleate from the diet (lower in CS vs. MF) by activating the associated biosynthesis metabolic pathway while the liver adaptively activated potassium transport to compensate for a lower K ingestion.

Different milk replacers alter growth performance and rumen bacterial diversity of dairy bull calves

The diets of calves predominantly comprise milk and the start of solid feed intake triggers a critical process in terms of the activity of the rumen microbiota and ruminal fermentation. However, little is known about alterations of the rumen bacterial diversity in dairy bull calves induced by milk replacers and other starters, such as solid pellets or hay. Thus, we analyzed the effects of partially replacing milk with pellets and Chinese wildrye in the diet on the growth performance and rumen bacterial composition in dairy bull calves. Thirty-two newborn Holstein bull calves were randomly allocated to four dietary treatments: group MFC was fed milk replacer, pellet diet, and Chinese wildrye; group MFR was fed milk replacer and Chinese wildrye; group MCO was fed milk replacer and pellet diet; and group MIL was fed milk replacer only. The diets were provided for 1 week before the trial and for 7 weeks in the experiment. At the end of the experiment, three calves from each treatment were slaughtered to determine the growth performance and slaughter traits, and the rumen bacteria composition was analyzed by 16S rRNA gene sequencing. The body weight, withers height, body length, and heart girth were higher (P < 0.05) in the MCO and MFC groups compared with the MIL and MFR group. In addition, the fresh weights of the liver, spleen, lung, kidney, rumen, reticulum, and abomasum were higher (P < 0.05) in the MCO and MFC groups. The sequencing results showed that at both the phylum and genus levels, the MIL and MFR groups clustered together, whereas the MCO and MFC groups clustered together. Bacteroidetes and Proteobacteria were more abundant in the MIL and MFR groups, whereas Firmicutes were more abundant in the MFC and MCO groups. The abundances of genera such as Dialister, Megasphaera, Acidaminococcus, and Mitsuokella were higher (P < 0.05) in the MCO and MFC groups. Our results showed that the growth performance of calves could be increased by feeding milk replacer with pellet diet, which may have been associated with changes in the diversity or abundances of rumen bacteria, especially bacteria from the phylum Firmicutes.

Estimating ruminal crude protein degradation from beef cattle feedstuff

We estimated ruminal crude protein degradation of twelve feedstuffs commonly used in China using in vitro and in vivo methods. The in vivo net protein utilization (NPU) levels of corn, sorghum, barley, wheat, Chinese wild rye grass, corn stalk, rice straw, soybean straw, soybean meal, distillers’ dried grains with solubles (DDGS), Brewers’ spent grains, and sunflower meal were 52.57, 49.68, 65.38, 72.58, 82.41, 72.26, 68.57, 76.95, 54.75, 56.27, 29.03 and 41.88%, respectively. The linear regression between NH3-N incorporated into microbial proteins and gas production after incubation (6, 12, and 24 h) was significant (r = 0.9948 and P < 0.001, r = 0.9874 and P < 0.01, and r = 0.9912 and P < 0.01, respectively). Based on the linear regression equations, we estimated in vitro protein degradability (IVPD) and generated the regression equations between IVPD and NPU. The linear regression equations between IVPD and NPU after 6 h incubation in the energy, protein, and roughage feed groups were Y = 0.5633X + 33.20 (R2 = 0.8517, P < 0.05), Y = 0.8482X+ 34.81 (R2 = 0.8650, P < 0.05), and Y = 1.6295X − 17.70 (R2 = 0.909, P < 0.05), respectively. The in vitro gas production method is useful for the determination of protein degradation in feedstuffs.

Low‐quality rice straw forage increases the permeability of mammary epithelial tight junctions in lactating dairy cows

It is known that milking frequency and plasma hormones play important roles in regulating mammary permeability. However, it is still not known whether nutritional factors can influence udder permeability. This study was conducted to investigate mammary epithelial tight-junction permeability in lactating dairy cows fed different forage-based diets. Twenty mid-lactating dairy cows were allocated to ten blocks based on their parity and milk yield and then randomly assigned into rice straw-based diet and alfalfa-based diet groups. Both diets contained 15% corn silage and 55% concentrate (dry matter basis). In terms of forage sources, rice straw-based diets (RS) contained 30% rice straw, whereas alfalfa-based diets (AH) contained 23% alfalfa hay plus 7% Chinese wild rye hay. The concentrations of Na+ , Na+ /K+ ratio, bovine serum albumin, and plasmin in the milk, the plasma lactose concentration, and the mRNA abundance of BCL2 associated agonist of cell death, phosphatase and tensin homolog, and insulin like growth factor binding protein 5 in the mammary gland were greater in RS-fed cows than in AH-fed animals. Mammary expression of proliferating cell nuclear antigen and occludin was lower in RS-fed cows compared with the AH-fed group. The expressions of growth hormone receptor, claudin-1, -3, -4, and ZO-1 were similar in the two diet groups. The cows fed RS showed higher mammary alveolar permeability, likely due to its effect on proliferation/apoptosis rates of mammary epithelial cells. © 2018 Society of Chemical Industry.

Effects of eucalyptus oil and anise oil supplementation on rumen fermentation characteristics, methane emission, and digestibility in sheep.

The objective of this study was to evaluate antimethanogenic activity of eucalyptus oil (EUC) and anise oil (ANI) in vitro and in vivo using sheep as a model. In vitro study was conducted using batch culture technique, each of EUC and ANI were added at 0, 50, 100, 200, or 400 mg/L of fermentation media with substrate containing 60% corn-based concentrate and 40% hay (DM basis). Total gas production (GP) linearly (P < 0.01) decreased with increasing ANI, whereas the GP was not affected with EUC addition. Supplementation of ANI and EUC linearly (P < 0.01) decreased total methane production and methane proportion in total gas. Total VFA and ammonia-nitrogen (NH3-N) concentration linearly (P < 0.01) decreased with increasing ANI supplementation. For the in vivo study, a replicated 3 × 3 Latin square design was carried out using six ruminal cannulated Du Han hybrid sheep (BW, 64.5 ± 8.56 kg) with 22 d of periods. Three treatments were control diet (consisted of 60% corn-based concentrate and 40% Chinese wildrye hay), EUC (control diet supplemented with 0.5 g EUC/d per head), and ANI (control diet supplemented with 0.5 g ANI/d per head). Each period consisted of 14 d for adaption and 8 d for sampling and data collection. Supplementation of EUC and ANI had no effects on feed intake and apparent nutrient digestibility. Ruminal NH3-N concentration was greater with EUC (P < 0.01) and ANI (P = 0.03) than control. Urinal allantoin output was less (P < 0.05) in sheep fed EUC and ANI than control animals. Methane emission was less (P = 0.03) in sheep fed ANI than sheep fed EUC, and a tendency of decrease for an eduction in this parameter was found for sheep fed with ANI (P = 0.08) compared to control. The in vitro results indicated a reduction of methane production with both EUC and ANI but in a dose-dependant manner. Supplementation of ANI tended to reduce ruminal methane production without adversely affecting rumen fermentation characteristics, nutrient intake, and digestibility, suggesting potential inhibition of ruminal methane emission in sheep supplemented with ANI.

Intermittent feeding of citrus essential oils as a potential strategy to decrease methane production by reducing microbial adaptation

The objective of the present study was to assess the effects of citrus essential oils (CEO) on growth and rumen fermentation of Hu sheep as well as to evaluate the effects of intermittent feeding of CEO to decrease methane production by reducing microbial adaptation in an in vitro batch culture system. Growth and rumen fermentation without CEO supplementation (W0_NE) and with supplementation with 0.8 mL CEO/L rumen volume from week 1 to week 3 (W1_EO, W2_EO, and W3_EO), as well as 2 additional weeks without CEO (W5_NE), were examined in 5 rumen-fistulated Hu sheep. Rumen fermentation and gas production of three substrates, corn meal (CM), Chinese wild rye hay (WH), and mixed feed (MF) of WH + concentrate (2:1, dry matter basis), and three doses of CEO (0, 0.8 and 1.6 mL/L) were tested in rumen fluid collected from W0_NE, W1_EO, W3_EO, and W5_NE in vitro. The results showed the CEO had no significant effects (P > 0.05) on body weight, average daily gain, dry matter intake and total-tract apparent digestibility. The CEO altered nitrogen metabolism and was characterized by reductions (P < 0.01) of the concentrations of blood urea nitrogen and rumen ammonia nitrogen. CEO decreased the concentrations of total and individual volatile fatty acids as well as the acetate to propionate ratio in vivo (P < 0.01). Anti-methanogenic effects of CEO were observed in W1_EO (P < 0.05) without additional CEO supplementation, but they were only observed in W3_EO and W5_NE with additional CEO supplementation. These results suggest that CEO introduce selective pressure on rumen microbes and induce methanogenesis adaptation in microbial communities. Intermittent feeding of CEO might be a potential strategy to decrease methane production by reducing the ability of microbes to adapt.

The particulate passage rate, nutrient composition and fermentation characteristics across gastrointestinal tracts in lactating dairy cows fed three different forage source diets

This study was conducted to investigate the particulate passage rate, nutrient characteristics and fermentation parameters across the gastrointestinal tract (GIT) in lactating dairy cows fed cereal straws in comparison with alfalfa hay. Eighteen multiparous Holstein cows were randomly assigned to one of three experimental diets consisting of 55% concentrate, 15% corn silage and 30% different forage sources as follows (% of dry matter [DM]): (i) 23% alfalfa hay and 7% Chinese wild rye hay (AH); (ii) 30% corn stover (CS); and (iii) 30% rice straw (RS). The Cr-mordanted corn silage-neutral detergent fibre was used to estimate the passage flow at week 14. After 14-week feeding, the animals were slaughtered to collect the gastrointestinal digesta. Dietary forage sources had little effect on the fractional passage rates in the rumen (range from 5.05 to 6.25%/hr) or hindgut (range from 4.49 to 5.24%/hr). Total volatile fatty acid (VFA) concentration in the caecum was highest, followed by the rumen, colon and rectum, and the lowest in the abomasum and duodenum, indicating that the large intestines, especially caecum, are the important positions for carbohydrate degradation. Greater proportion of propionate and butyrate and lower acetate were found in the AH compared to CS or RS in colon, but higher acetate in abomasum was found in the cows fed CS or RS compared to AH. In conclusion, cereal straw diets did not change the particulate passage rate in the rumen and hindgut which might be mainly due to the similar DM intake among these three diets. Different forage source diets significantly changed VFA proportion in the abomasum and colon, indicating the existence of different digestion or absorption rates in these tracts among the experimental diets.

Components of feed affecting water footprint of feedlot dairy farm systems in Northern China

Abstract Freshwater consumption in animal agriculture is a significant factor affecting water resources and water environmental sustainability. Water footprint (WF), as a comprehensive assessment indicator, can be used to assess the consumptive water use in the dairy sector. The aim of this study was to assess the effects of feed components on the water consumption and WF of milk production for collective feedlot systems in China. Fourteen dairy farms, with a range of dairy cow numbers, were used as examples for the analysis. The results indicated that the average WF of milk was 882 L kg−1 FPCM (fat-and-protein-corrected milk), ranging from 639 to 1307 L kg−1 FPCM. The WF from Chinese wildrye hay, maize grain, alfalfa hay and soybean meal production accounted for 30.4%, 16.4%, 14.5% and 10.9% of the total WF, respectively, whereas the WF from embedded in animal products, respiratory vapour losses and other service water was 11.4%, implying that water consumption due to evapotranspiration from feed production was the major driver of the milk WF for the collective feedlot system in China. The variation in WF among the different dairy farms was mainly associated with the different components in the feed, which affected not only the milk productivity and feed conversion efficiency, but also the water consumption for milk production. Increase in the proportion of Chinese wildrye hay in roughages reduced the milk productivity of the cow and also increased the WF of milk. Scenario analysis indicated that using feed that consumes less water to produce or importing feed from a country where its water consumption is lower could reduce the consumptive water use for milk production by up to 22%. The results show how changing feed components and origin can reduce the freshwater consumption in livestock sectors in China.

Effects of dietary forage to concentrate ratio and wildrye length on nutrient intake, digestibility, plasma metabolites, ruminal fermentation and fecal microflora of male Chinese Holstein calves

Twenty-eight male, weaned Chinese Holstein calves ((156.8±33.4) kg) were used to investigate the effects of dietary forage to concentrate ratio (F:C) and forage length on nutrient digestibility, plasma metabolites, ruminal fermentation, and fecal microflora. Animals were randomly allocated to four treatments in a 2×2 factorial arrangement: whole-length forage (WL) with low F:C (50:50); WL with high F:C (65:35); short-length forage (SL) with high F:C (65:35); and SL with low F:C (50:50). Chinese wildrye was used as the only forage source in this trial. The grass in the SL treatments was chopped using a chaff cutter to achieve small particle size (∼50% particles >19 mm). Dry matter intake (DMI) and organic matter (OM) intake was increased by increasing both F:C (P<0.01) and forage length (FL) (P<0.05), while acid detergent fiber (ADF) and neutral detergent fiber (NDF) intakes were only increased by increasing the F:C (P<0.01). The digestibility of NDF was increased as the FL increased (P<0.01), and it was also affected by interaction between F:C and FL (P<0.05). Cholesterol (CHO) (P<0.01), leptin (LP) (P<0.05), and growth hormone (GH) (P<0.01) concentrations in plasma were increased as dietary F:C increased. A significant increase in plasma triglyceride (TG) (P<0.01), insulin (INS) (P<0.05), and GH (P<0.01) levels was observed with decreasing dietary FL. Ruminal pH values of calves fed with low F:C diets were significantly lower than those in high F:C treatment (P<0.05). Increasing the F:C enhanced ruminal acetic acid (P<0.05) and acetic acid/propionic acid (P<0.01). Fecal Lactobacillus content was significantly higher, while Escherichia coli and Salmonella contents were significantly lower in WL and high F:C groups (P<0.05). Lower fecal scores (higher diarrhea rate) were observed in calves fed with SL hay compared to WL hay (P<0.05). Denatured gradient gel electrophoresis (DGGE) bands and richness index (S) were significantly affected by the interaction between F:C and FL (P<0.05), under high F:C, band numbers and richness index from WL group were higher than that from SL group (P<0.05), whereas there were no differences between WL and SL groups under low F:C (P>0.05). Microflora similarity was 50–73% among the different treatments. It is concluded that the WL with high F:C (65:35) diet is suitable for weaned calves.

Effect of cereal straw and alfalfa hay diet on amino acid profile of gastrointestinal digesta in lactating dairy cows.

This study was conducted to evaluate the effects of replacing alfalfa hay with rice straw (RS) or corn stover (CS) on amino acid (AA) profiles of gastrointestinal digesta in lactating cows. Eighteen lactating dairy cows were randomly assigned to one of three groups (n=6) and fed identical concentrate and corn silage with different forages on dry matter basis: (i) 23% alfalfa hay and 7% Chinese wild rye hay (AH); (ii) 30% CS; and (iii) 30% RS. After the 14-week feeding, a total of 18 cows were slaughtered to collect digesta from four representative organs, including rumen, omasum, duodenum and jejunum. The AA profiles of ruminal microbial fraction were similar among the treatments, except for greater Arg in cows fed RS than in cows fed AH or CS. Most of the analysed AA changed under different diets. Significant differences were found among the microbial fraction, rumen fluid and rumen digesta, with greater essential AA in digesta than in microbial fraction or rumen fluid and greater essential AA in microbial fraction than rumen fluid. Significant differences in individual AA profiles of digesta and relevant fluid were found across the four representative digestive tract parts, including rumen, omasum, duodenum and jejunum, showing much lower Leu proportion in CS and RS than in AH in duodenal fluid. In summary, ruminal microbes may prefer using essential AA, rather than non-essential AA. The AA profile of ruminal microbes was constant except for Arg. The AA composition of digesta across the four digestive tracts changed dramatically, which indicated differences in the ability and efficiency of AA absorption. The lower duodenum absorbable Leu proportion in cows fed CS or RS indicated the shortage of Leu in CS or RS diets, which might also restrict the balanced AA absorption.

Effects of different feeding methods and space allowance on the growth performance, individual and social behaviors of Holstein calves

The importance of nutrient provisions and weaning methods for calves has been well established over the past few years, while as increasing interest has focused on contribution of animal behavior and their overall performance in production regimes. The present study investigated the effects of feeding methods and space allowance on growth performance, individual and social behaviors in Holstein calves. Twenty-four Chinese Holstein male and female calves were allocated to either an individual or group of 6 and fed either with a bucket or a teat. Milk replacer, calf starter, and Chinese wildrye were offered during the experiment. A fecal index used in the present study was defined as the total fecal scores/total number of calves in each treatment. The results showed that there was no significant difference among the 4 treatments in terms of feed intake, body weight, average daily gain, and fecal index. For the feeding behaviors, the ingesting milk time and ingesting milk rate were significantly affected by space allowance, while the feeding methods showed a significant influence on the bunting behavior of the calves. There was no significant difference among the 4 treatments in terms of licking fixtures, self-grooming, and lying down behaviors, irrespective of the feeding method or space allowance. However, sucking an empty bucket or the teat was significantly affected by the feeding method. Several selected group behaviors were examined in the present study, and similar values for sniffing the other calves, social grooming, and cross-sucking behaviors were observed. Overall, the present study demonstrated that different feeding methods and space allowances had a significant effect on the feeding behavior of calves, while the feed intake, growth performance, health condition, individual and group social behaviors were not significantly influenced. Furthermore, under intensified production systems, Holstein calves raised in a group may obtain a similar production performance, thus reducing management input and profitability compared with those kept individually. However, there may be competition during the feeding period.

Responses of milk production of dairy cows to jugular infusions of a mixture of essential amino acids with or without exclusion leucine or arginine.

The purpose of this study was to determine effects of jugular infusion of either balanced or imbalanced amino acid mixture on milk production and composition in dairy cows. Eight mid-lactation Holstein cows were randomly assigned to 5-d continuous jugular infusions of saline (CTL), essential amino acid (EAA) mixture prepared on the profile of casein (CSN, 160 g/d), EAA mixture excluding leucine (Leu) (−Leu, 163 g/d) or EAA mixture excluding arginine (Arg) (−Arg, 158 g/d) in a duplicated 4 × 4 Latin square design with 4 infusion periods separated by a 7-d interval period. The basal diet was formulated with corn grain, soybean meal, cottonseed meal, corn silage, alfalfa hay and Chinese wildrye grass hay according to NRC (2001) and supplied 1.6 Mcal net energy for lactation (NEL) and 94.4 g metabolizable protein (MP) per kg dry matter (DM) to meet requirements for lactation. The results showed that the dry matter intake (DMI) and normal physiological status were not affected by amino acid mixture infusions. Compared with CTL treatment, the CSN treatment increased milk yield (14.9%, P < 0.001), milk lactose yield (14.5%, P = 0.001), milk fat yield (16.6%, P = 0.01), milk protein yield (18.2%, P < 0.001) and the contents of αS1-casein (αS1-CN, 11.8%, P = 0.007), β-casein (β-CN, 4.2%, P = 0.035) and κ-casein (κ-CN, 8.5%, P = 0.003). However, the −Leu and −Arg treatments had lower milk yield (6.3%, P = 0.058 and 5.7%, P = 0.073, respectively), milk protein yield (8.8%, P = 0.010 and 8.2%, P = 0.011, respectively) and the contents of αS1-CN (7.3%, P = 0.057 and 8.4%, P = 0.026, respectively), β-CN (4.2%, P = 0.033 and 3.8%, P = 0.048, respectively) and κ-CN (5.8%, P = 0.023 and 7.6%, P = 0.003, respectively) than those of the CSN treatment. Milk lactose yield (5.9%, P = 0.076) tended to decrease when Leu was removed from amino acid mixture infusate. In conclusion, the supply of casein profile can increase milk production in dairy cows, but a deficiency of Leu or Arg had negative effects on milk yield and milk protein yield.

Accuracy comparison of dry matter intake prediction models evaluated by a feeding trial of lactating dairy cows fed two total mixed rations with different forage source

Dry matter intake (DMI) prediction models of NRC (2001), Fox et al. (2004) and Fuentes-Pila et al. (2003) were targeted in the present study, and the objective was to evaluate their prediction accuracy with feeding trial data of 32 lactating Holstein cows fed two total mixed rations with different forage source. Thirty-two cows were randomly assigned to one of two total mixed ration groups: a ration containing a mixed forage (MF) of 3.7% Chinese wildrye, 28.4% alfalfa hay and 26.5% corn silage diet and another ration containing 33.8% corn stover (CS) as unique forage source. The actual DMI was greater in MF group than in CS group (P=0.064). The NRC model to predict DMI resulted in the lowest root mean square prediction error for both MF and CS groups (1.09 kg d−1 vs. 1.28 kg d−1) and the highest accuracy and precision based on concordance correlation coefficient for both MF and CS diet (0.89 vs. 0.87). Except the NRC model, the other two models presented mean and linear biases in both MF and CS diets when prediction residuals were plotted against predicted DMI values (P<0.001). The DMI variation in MF was caused by week of lactation (55.6%), milk yield (13.9%), milk fat percentage (7.1%) and dietary neutral detergent fiber (13.3%), while the variation in CS was caused by week of lactation (50.9%), live body weight (28.2%), milk yield (8.4%), milk fat percentage (5.2%) and dietary neutral detergent fibre (3.8%). In a brief, the NRC model to predict DMI is comparatively acceptable for lactating dairy cows fed two total mixed rations with different forage source.

Replacing alfalfa hay with dry corn gluten feed and Chinese wild rye grass: Effects on rumen fermentation, rumen microbial protein synthesis, and lactation performance in lactating dairy cows

This experiment was conducted to investigate nutrient digestibility, rumen microbial protein synthesis, and lactation performance when a portion of alfalfa was replaced with combinations of dry corn gluten feed (DCGF) and Chinese wild rye grass in the diet of lactating cows. Six multiparous and 3 primiparous Chinese Holsteins were arranged in a replicated 3 × 3 Latin square experiment for 21-d periods. The animals were fed 1 of 3 treatment diets during each period: (1) 0% DCGF (0DCGF); (2) 6.5% DCGF (7DCGF); and (3) 11% DCGF (11DCGF). Diets were isonitrogenous, and a portion of alfalfa hay was replaced with DCGF and Chinese wild rye grass, with similar concentrate mixtures and corn silage contents. The dry matter intake was greater for 11DCGF (21.9 kg/d) than for 0DCGF (20.7 kg/d) or 7DCGF (21.2 kg/d). The treatment diets did not result in difference in milk production, fat and lactose concentration, or yield. Compared with 0DCGF, the ration containing 11% DCGF improved the milk protein concentration. Dry matter and neutral detergent fiber digestibility was greater for 7DCGF (62.7% and 45.6%) and 11DCGF (63.1% and 47.2%) than for 0DCGF (59.4% and 42.3%), and the nitrogen digestibility was similar for the 3 treatments. The concentration of rumen volatile fatty acids was higher in cows fed the 11DCGF diet than in those fed the 0DCGF diet, with no difference between the 7DCGF and 11DCGF diets. The estimated microbial crude protein yield was greater for the 11DCGF diet (1985.1 g/d) than for the 0DCGF diet (1745.0 g/d), with no difference between the 0DCGF and 7DCGF diets. Thus, it appears that feeding DCGF and Chinese wild rye grass in combination can effectively replace a portion of alfalfa hay in the rations of lactating dairy cows.

Effect of Different Roughages on Milk Protein and Milk Fat Synthesis in Dairy Cows

The main purpose of this study was to determine the effect of a corn straw or mixed diet on milk production, milk composition and the expression of genes associated with lactation in mid-lactation Chinese Holstein cows. In this study, 10 healthy Chinese Holstein cows were randomly assigned to two groups and fed with different diets respectively, corn straw (CS) or mixed forage (MF) diet. CS group was fed roughage consisting of 53.8% corn straw only and the forge to concentrate (F : C) ratio [dry matter (DM)] was about 40: 60. MF group was fed roughage consisting of 3.7% Chinese wildrye and 23.4% alfalfa hay, the forge to concentrate (F : C) ratio (DM) was 70: 30. All the cows were fed 8 weeks and body weight, dry matter intake, body condition score, fat, protein, lactose, milk yield, total solid and somatic cell count (SCC) were recorded. Quantitative real-time PCR (qRT-PCR) was used to analyze cow mammary gland samples representing two different diets. The results suggested that different diet types had significant effects on milk yield, lactose, milk fat, milk protein, dry matter intake and somatic cell count in dairy cows, and cows fed MF diet improved milk production and lactation performance clearly (P<0.05). In addition, mRNA expression of genes ACC, mTOR, STAT5, CSN2, PPARγ, FABP3 and PTEN in MF group was extremely significantly higher than that in CS group (P<0.05). mRNA expression of AKT1, FAS, SCD and SREBP1c in MF group was significantly higher than that in CS group (P<0.01). In summary, the milk yield and composition in mixed forage group were significantly improved than those in corn straw group.

An insufficient glucose supply causes reduced lactose synthesis in lactating dairy cows fed rice straw instead of alfalfa hay.

The objective of the present study was to investigate the nutrient availability for milk production in the mammary gland of lactating cows fed different forage-based diets. The 3 diets contained 30% corn stover (CS), 30% rice straw (RS), or 23% alfalfa hay plus 7% Chinese wild rye hay (AH) as a forage source. All diets contained 15% of DM as corn silage and 55% of DM as concentrate. The percentage of milk lactose was always lower in the RS-fed cows than in the cows fed AH or CS during the 12-wk feeding trial ( < 0.01). Ruminal propionate concentrations were lower in the RS group than in the AH group ( = 0.03). The ratio of insulin to glucagon in the mammary venous plasma was greater in the AH group than in the CS or RS group ( = 0.04). The abundance of the pyruvate carboxylase mRNA in the liver was lower in the RS group than in the AH or CS group ( = 0.04), and the abundance of mitochondrial phosphoenolpyruvate carboxykinase, IGF-1 receptor, and phosphofructokinase-liver, phosphofructokinase-muscle, and phosphofructokinase-platelet mRNA in the liver were lower in the RS group than in the AH group ( < 0.05). The mammary glucose uptake was greater in the AH-fed cows than in the CS- or RS-fed cows ( = 0.02). The mRNA abundance of the glucose transporters in the mammary gland was similar among the 3 treatments. The mRNA abundance of α-lactalbumin in the mammary gland of the cows fed RS tended to be greater compared with that of the cows fed AH or CS. The milk potassium concentration was greater in the cows fed RS than those fed AH or CS ( < 0.01). In summary, the insufficient ruminal propionate concentrations in the cows fed RS were associated with lower gluconeogenesis in the liver, resulting in the shortage of glucose supply for mammary utilization.