Effects of forage offering method on performance,rumen fermentation,nutrient digestibility and nutritional behaviour in Holstein dairy calves

The potential effect of dietary forage supplementation on the performance and rumen development in dairy calves is well established. However, limited research has been directed to the comparative effects of forage offering methods on calf performance. The objective of the present study was to determine the effects of forage provision methods (total mixed ration or free choice) on the performance, nutrient digestibility, rumen fermentation and nutritional behaviour in newborn calves. Forty‐five Holstein dairy calves (3 days of age and 41 ± 2 kg of body weight) were assigned to the following three groups (n = 15): (i) starter without forage provision (CON), (ii) starter supplemented with 10% alfalfa hay (AH) as a total mixed ration (AH‐TMR) and (iii) starter and AH as a free‐choice provision (AH‐FC) for a period of 70 days. All the calves were offered 5 l of milk/day from day 3 to 50, and 2.5 l/day from day 50 until weaning on day 56. Dry matter intake (DMI) was greater (p < 0.01) in the AH‐TMR and AH‐FC treatments than in the CON during the pre‐ and post‐weaning periods. Calves fed the AH‐FC diet showed the highest post‐weaning DMI among the treatments. The calves receiving ad libitum forage tended (p = 0.08) to increase crude protein digestibility and overall volatile fatty acids (VFA) concentrations in the rumen. No differences were observed among the treatments at the time spent on standing, lying, eating and performing non‐nutritive oral behaviours. Compared to CON calves, animals in the AH‐TMR treatment spent more time (p < 0.05) ruminating. In conclusion, our data suggest that forage supplementation in both forage offering methods increased total DMI, ruminal pH and ruminating time in dairy calves. Hence, there is no benefit in the free‐choice provision of AH in dairy calves.     

Strategies of supplementation of female suckling calves and nutrition parameters of beef cows on tropical pasture

The performance of female calves in creep feeding under different strategies of supplementation and milk production, intake, and digestibility of grazing Nellore and crossbred cows (Nellore?×?Holstein) during the dry-rainy transition season were assessed. Forty-four female beef suckling calves, with initial age between 90 and 150?days and average initial body weight of 117.7?±?4.3?kg, and their respective dams (24 Nellore and 20 crossbred) with average initial body weight of 417.5?±?8.3?kg, were used. The experimental treatments consisted of: control group-mineral mixture only; strategy 1-supplementation from 112?days prior to weaning (0.375?kg/animal/day); strategy 2-supplementation from 112?days prior to weaning, in increasing amounts of 0.15, 0.30, 0.45, and 0.60?kg/animal/day through the four experimental periods, respectively; and strategy 3-supplementation from 56?days prior to weaning (0.750?kg/animal/day). Calves from strategy 1 had greater (P??0.05) for nutrient digestibility among genetic types. It can be concluded that strategies of supplementation that present an equitable distribution of supplement provides greater weight gain in suckling female beef calves. Crossbred cows produce more milk and present greater DMI than Nellore cows. There are no differences in the nutrient digestibility between Nellore and Nellore × Holstein crossbred cows.     

布拉氏酵母对哺乳期犊牛生长性能、营养物质消化率和血清生化指标的影响

试验旨在研究布拉氏酵母菌对哺乳犊牛的生长性能、营养物质表观消化率和血清生化指标的影响。选择48头初生体重(38.16±3.73)kg且健康状况良好的中国荷斯坦犊牛,随机分为4组,每组12头,公母对半。各处理组饲粮中分别添加0(对照)、1(Ⅰ组)、3(Ⅱ组)、5(Ⅲ组)g/(天·头)的布拉氏酵母,整个试验共42 d。结果表明:(1)试验第21天,Ⅱ、Ⅲ组犊牛体重显著高于对照组(P<0.05);试验组犊牛1~21 d平均日增重(ADG)和平均日采食量(ADMI)均显著高于对照组(P<0.05);1~21 d的饲料转化率(F/G)试验组显著低于对照组(P<0.05);Ⅱ、Ⅲ组犊牛21 d胸围和胸深显著高于对照组(P<0.05)。(2)试验第42天,Ⅱ组犊牛干物质(DM)、粗蛋白质(CP)、粗脂肪(EE)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)的消化率显著高于对照组(P<0.05)。(3)试验第21天,Ⅱ组犊牛血清总蛋白(TP)和球蛋白(GLB)浓度均显著高于对照组(P<0.05);试验第42天,Ⅱ、Ⅲ组犊牛血清甘油三酯(TG)浓度显著降低(P<0.05)。综合分析,在犊牛前期的饲粮中添加布拉氏酵母,能提高犊牛的生长性能,促进营养物质的消化吸收,添加3 g(1.38×1010 CFU/g)布拉氏酵母的效果最佳。     

不同品质粗饲料对断奶至7月龄犊牛生长发育及营养物质消化率的影响

选用从哺乳期开始分别补饲玉米秸秆(CFS组)和青干草(H组)的两组试验犊牛(n=5)。断奶后继续分别饲喂CFS和H,定量饲喂精料（2 kg/d）。通过消化试验和饲养试验,跟踪研究了饲喂不同品质粗饲料对断奶到7月龄阶段犊牛营养物质摄入量、消化率和生长发育的影响。结果显示,7月龄时,CFS和H组日采食量分别为2.25和3.81 kg（P<0.01）;H组和CFS组比较,DMI、NDF、ADF、CP、Fat摄入量明显提高,其消化率分别为63.6%、51.2%、43.5%、64.3%、55.6%和57.5%、43.3%、40.4%、44.4%、59.4%,除了CP消化率差异极显著外（P<0.01）,其余均不显著（P>0.05）;H组和CFS组日增重(kg/d)差异极显著（0.788和0.522 kg/d,P<0.01),体斜长增量（18.3和9.5 cm）和胸围增量(24.1和18.6 cm)差异显著(P<0.05),体高增量（14.0和9.7 cm）差异不显著（P>0.05）。结果表明,给断奶至7月龄阶段犊牛饲喂混合青干草比饲喂玉米秸秆,更能提高粗饲料采食量和干物质总摄入量,有利于营养物质消化利用,促进犊牛生长发育,尤其对体长和胸围的发育效果明显。     

The effects of increasing garlic powder and monensin supplementation on feed intake,nutrient digestibility,growth performance and blood parameters of growing calves

The objective of this study was to evaluate the effects of increasing garlic powder and monensin supplementation on feed intake, nutrient digestibility, growth performance and blood metabolites of growing calves. Forty Holstein calves (BW = 100 ± 11 kg) were randomly assigned to four dietary treatments (n = 10) in a complete randomized design. Experimental treatments consisted of the following: (i) basal diet (control), (ii) basal diet supplemented with 0.0003% of dietary dry matter (DM) sodium monensin, (iii) low level of garlic powder (Low‐GAR; 0.5% of dietary DM) and (iv) high level of garlic powder (High‐GAR; 1% of dietary DM). DM intake (DMI) and DM digestibility were (p < 0.05) decreased by High‐GAR. However, calves supplemented with Low‐GAR had a similar DMI to the control calves and similar DM digestibility to the control and monensin groups. The digestibility of other nutrients were not affected by the treatments. Although supplementing monensin relative to Low‐GAR increased the DMI (p < 0.05), average daily gain was similar between Low‐GAR and monensin supplemented calves, which were higher than the control and High‐GAR groups (p < 0.05). As a result, feed conversion ratio was improved in the Low‐GAR group versus other treatment groups (p < 0.05). Administrating garlic powder decreased the blood low‐density lipoprotein (LDL) and non‐esterified fatty acids (p < 0.05) without affecting the blood triglyceride, high‐density lipoprotein and beta‐hydroxybutyric acid concentrations. In conclusion, the calves fed the Low‐GAR showed an improved FCR and blood metabolites without changing the DMI and nutrient digestibility. It suggests that garlic powder could be used as an alternative to monensin for growing calves under the current feeding conditions.     

Effects of plane of nutrition on growth,feed intake,digestibility and nitrogen balance in Murrah graded male buffalo (Bubalus bubalis) calves in Nepal

An experiment was conducted using 17 male buffalo calves to assess the effects of plane of nutrition on dry matter intake (DMI), daily gain (DG), body size measurement, apparent digestibility and nitrogen (N) balance. To attain 250 kg BW, the calves were allocated into three groups: H, L‐H and L, receiving the concentrate at 1.50% of BW, 0.75% of BW until 190 kg BW and 1.50% thereafter and 0.75% of BW, respectively. The animals had ad libitum access to urea‐treated rice straw (UTRS). The DMI of UTRS through the experiment was higher in L and L‐H than H, showing 3.52, 2.90 and 2.62 kg/day, respectively (P < 0.01), but the total DMI did not differ among the treatment groups. The DG throughout the experiment was high in the order of H, L‐H and L, showing 0.72, 0.57 and 0.45 kg, respectively (P < 0.01). The digestibility of DM, organic matter, crude protein, neutral and acid detergent fiber and N retention were higher in H than in L (P < 0.05). The findings of this study thus revealed the greater DG has an advantage of shortening the growing period around 3 months, and consequently increasing benefit in fattening of buffalo calves in Nepal.     

Effect of varying ruminally degradable to ruminally undegradable protein ratio on nutrient intake, digestibility and N metabolism in Nili Ravi buffalo calves (Bubalus bubalis)

Four Nili-Ravi buffalo calves (100 ± 4 kg) were used in 4 × 4 Latin Square Design to evaluate the influence of varying ruminally degradable protein (RDP) to ruminally undegradable protein (RUP) ratio on dry matter intake (DMI), digestibility and nitrogen (N) metabolism. Four experimental diets A, B, C and D were formulated to contain RDP:RUP of 70:30, 65:35, 60:40 and 55:45, respectively. The calves were fed ad libitum. Dry matter intake by calves fed C diet was higher (P < 0.05) than those fed D diet and lower (P < 0.05) than calves fed A diet, however, it was similar to those fed B diet. There was a linear decrease (P < 0.01) in DMI with decreasing the RDP to RUP ratio. Similar trend was noticed in crude protein (CP) intake. Neutral detergent fiber (NDF) intake was significantly different across all treatment. The decrease in CP and NDF intake was due to decreasing trend of DMI. Dry matter (DM) digestibility in calves fed A and B diets was higher (P < 0.05) than those fed C and D diets. A linear decrease (P < 0.01) in DM digestibility was observed with decreasing the RDP to RUP ratio. Crude protein digestibility remained unaltered across all treatments. Neutral detergent fiber digestibility was higher in calves fed A and B diets than those fed C and D diets. Higher NDF digestibility in calves fed A and B diets was due to higher level of dietary RDP that might resulted in higher ruminal ammonia concentration which stimulate activity of cellulytic bacteria and ultimately increased NDF digestibility. The N retention (g/d) was similar among the calves fed B, C and D diets, however, it was higher (P < 0.05) than those fed A diet. Decreasing the RDP to RUP ratio resulted in linear increase (P < 0.01) in N retention. The N retention, as percent of N intake was significantly different across all treatments. Decreasing RDP to RUP ratio resulted in linear increase (P < 0.01) in N retention, as percent of N intake. A similar trend was noticed in N retention, as percentage of N digestion. Blood urea nitrogen (BUN) concentration in calves fed B diet was higher (P < 0.05) than those fed D diet and was lower (P < 0.05) than those fed A diet, however, it was not different from calves fed C diet. Decreasing dietary RDP to RUP ratio resulted in linear decrease (P < 0.05) in BUN concentrations. The decrease in BUN concentration was because of decreasing level of dietary RDP. The N retention can be increased by decreasing RDP to RUP ratio in the diet of growing buffalo calves and diet containing RDP to RUP ratio 55:45 is considered optimum regarding N retention in buffalo calves.     

Vitamin E supplementation of newly arrived feedlot calves

Seven hundred fifteen crossbred (primarily British) calves purchased in southern Oklahoma and northern Texas auction barns were received at the Willard Sparks Beef Research Center, Stillwater, OK, and used to study effects of duration (days) of vitamin E feeding during a 42-d receiving period on animal performance, health, and serum cholesterol and vitamin E concentrations. Upon arrival, calves were blocked by load (seven loads), sorted by BW (light, n = 4 pens per load; and heavy, n = 4 pens per load), and assigned randomly to one of four dietary treatments (n = 2 pens per load; 14 pens per treatment). Experimental diets were formulated to provide 2,000 IU.calf(-1).d(-1) of supplemental vitamin E (dl-alpha-tocopherol acetate) for 0 (CON), 7 (E7), 14 (E14), or 28 (E28) d. Vitamin E was delivered in a pelleted supplement that was added to the basal diet in decreasing concentrations as DMI increased (2.0 kg of DMI = 6%; 4.0 kg of DMI = 4%; and 6.0 kg of DMI = 2%). Serum samples were collected on d 0, 14, 28, and 42 for determination of cholesterol, alpha-tocopherol (d 0, 28, and 42), and antibody (IgG) concentrations. Duration of vitamin E supplementation did not affect ADG (0.98 kg/d; P = 0.56) or G:F (0.189; P = 0.87). Serum cholesterol concentrations decreased (day effect; P < 0.001) for all treatments from d 0 (average = 127 mg/100 mL) to 14 (average = 62 mg/100 mL). Serum alpha-tocopherol decreased (day effect; P < 0.001) from d 0 (5.2 microg/mL) to 28 (1.8 microg/mL); however, on d 28, a greater (P < 0.001) serum alpha-tocopherol concentration was observed for E28 (3.4 microg/mL) calves than for CON (1.1 microg/mL), E7 (1.2 microg/mL), or E14 (1.5 microg/mL) calves. Respiratory disease was diagnosed in 64.6% of calves in this study. Medical costs were less (P = 0.08) for calves fed vitamin E for 28 d (4.88 dollars/calf) than for calves fed the control diet (6.29 dollars/calf). Carcass characteristics were not affected (P = 0.19 to 0.88) by dietary treatments. Supplemental vitamin E formulated for 2,000 IU.calf(-1).d(-1) had little influence on performance and overall health status of calves under our experimental conditions; however, the increased serum concentrations of alpha-tocopherol when vitamin E was fed for 28 d suggests that any potential effects of vitamin E on health status might be time-dependent.     

Effects of limited concentrate feeding on growth and blood and serum variables, and on nutrient digestibility and gene expression of hepatic gluconeogenic enzymes in dairy calves

This study elucidated the effects of limited concentrate feeding on growth, nutrient digestibility, blood profile and gene expression of gluconeogenic enzymes in the liver of dairy calves. The study utilized 36 German Holstein dairy calves (5-7 days of age) divided into two groups of 18 calves each for 150 days. Control group calves received 2 kg/(calf × day) of concentrate, whereas calves in the restricted group received only 1 kg/(calf × day). Good quality forage (mixture of maize and grass silages) was available for ad libitum consumption to both groups. The intake of milk replacer before weaning, and of concentrate were recorded daily per calf; however, the consumption of forages was quantified as daily average of the group. Body weights (BW) were recorded at start and on days 35, 70, 112 and 150. Blood and serum samples and spot urinary and faecal samples were also collected at similar time points. On days 70 and 150, liver biopsies were collected from seven animals in each group. The BW was not different between the groups at all times. Total BW gain in the control group was 124 kg as opposed to 111 kg in restricted group that led to average BW gain of 827 g/day and 739 g/day in respective groups, and the differences were significant (p = 0.018). As planned, the control group had higher concentrate and lower forage intake than the restricted group. The blood haemoglobin, haematocrit and serum variables (glucose, total protein, albumin and urea) were within the normal range in both groups, but serum glucose was higher (p < 0.05) in control than in restricted group at 70 days. There was no difference between groups in organic matter (OM) digestibility which declined (p < 0.001) with increasing age in both groups. Microbial crude protein (MCP) synthesis estimated from urinary allantoin excretion increased (p < 0.001) in both groups with increasing age but was not different between groups. The mRNA expressions for the gluconeogenic enzymes, cytosolic and mitochondrial phosphoenol pyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1) measured by quantitative real-time PCR in liver biopsies showed no differences between groups. Overall, restricting concentrate moderately reduced the growth intensity without affecting the normal serum and blood indices, and MCP synthesis and OM digestibility showed no differences between groups, indicating that both concentrate feeding schemes can be successfully applied.     

不同中性洗涤纤维与非纤维性碳水化合物比值饲粮对肉用绵羊甲烷排放的影响

本试验旨在研究不同中性洗涤纤维(NDF)与非纤维性碳水化合物(NFC)比值(NDF/NFC)饲粮对肉用绵羊甲烷排放的影响。试验采用4×4完全拉丁方试验设计,将16只杜泊×小尾寒羊杂交羯羊随机分成4组,每组4只,按维持水平饲喂NDF/NFC分别为3.02(饲粮1)、2.32(饲粮2)、1.58(饲粮3)、1.04(饲粮4)的全混合颗粒饲粮(玉米秸秆为粗饲料来源)。试验共进行4期,每期18 d,包括3 d的调整期、7 d的预试期和8 d的正试期,在正试期内测定甲烷产量、饲粮总能和营养物质表观消化率。结果表明:饲粮2的甲烷日排放量显著高于饲粮3和4(43.43 L/d vs.38.88和35.98 L/d;P0.05)。与饲粮1相比,饲粮2和3的每千克干物质采食量(DMI)甲烷排放量显著增加(38.00 L/kg DMI vs.42.24、41.69 L/kg DMI;P0.05),但是饲粮2、3和4之间差异不显著(P0.05)。随着NDF/NFC的降低,每千克可消化有机物(DOM)的甲烷排放量逐渐降低,饲粮4的每千克DOM的甲烷排放量显著低于饲粮1、2和3(58.78 L/kg DOM vs.75.00、73.35和64.11 L/kg DOM;P0.05)。随着NDF/NFC的降低,每千克中性洗涤纤维采食量(NDFI)或酸性洗涤纤维采食量(ADFI)的甲烷排放量逐渐增加,且各饲粮之间差异显著(P0.05)。综上所述,结合各营养物质表观消化率和甲烷排放效率,在维持水平下,采用NDF/NFC为1.04的玉米秸秆饲粮作为肉用绵羊甲烷减排的饲粮最合适。     

Intake, selection, digesta retention, digestion and gut fill of two coprophageous species, rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus), on a hay-only diet

A colonic separation mechanism (CSM) is the prerequisite for the digestive strategy of coprophagy. Two different CSM are known in small herbivores, the 'wash-back' CSM of lagomorphs and the 'mucous-trap' CSM of rodents. Differences between these groups in their digestive pattern when fed exclusively hay were investigated in six rabbits (Oryctolagus cuniculus) and six guinea pigs (Cavia porcellus). Intake, digestibility (by total faecal collection), solute and particle mean retention times (MRT, using Co-EDTA and Cr-mordanted fibres) were measured. Rabbits selected less fibrous parts of the hay than guinea pigs, leaving orts with higher content of neutral detergent fibre [NDF; 721 ± 21 vs. 642 ± 31 g/kg dry matter (DM) in guinea pigs]. They also expressed a lower NDF digestibility (0.44 ± 0.10 vs. 0.55 ± 0.05 of total), a similar particle MRT (15 ± 3 vs. 18 ± 6 h), a longer solute MRT (51 ± 9 vs. 16 ± 4 h), and a lower calculated dry matter gut fill (19.6 ± 4.7 vs. 29.7 ± 4.1 g DM/kg body mass) than guinea pigs (p < 0.05 for each variable). These results support the assumption that the 'wash-back' CSM, exhibited in the rabbits, is more efficient in extracting bacterial matter from the colonic digesta plug than the 'mucous-trap' CSM found in the guinea pigs. Related to metabolic body mass, rabbits therefore need a less capacious colon for their CSM where a more efficient bacteria wash-out is reflected in the lower fibre digestibility. A lighter digestive tract could contribute to a peculiarity of lagomorphs: their ability to run faster than other similar-sized mammals.     

犊牛代乳粉对早期断奶犊牛生长发育的影响

选用出生后吃完初乳的荷斯坦母犊24头分为试验组和对照组,对照组饲喂鲜牛奶6kg/d/头,试验组饲喂代乳粉800g/d/头。结果表明:经过60d的饲喂试验,试验组比对照组多增重5.31kg(P<0.01),试验组犊牛日增重比对照组提高了88.5g(P<0.01),试验组犊牛的体高和胸围的增长速度均高于对照组。从经济效益来看,进食代乳粉组犊牛比对照组节省成本263.42元/头(鲜奶价格按2元/kg计算)。     

Effects of a Brown‐midrib corn hybrid on nutrient digestibility in wethers and on dry matter intake,performance, rumen and blood variables in dairy cows

The aim of the present trials was to determine the effect of an experimental Brown‐midrib (Bm) corn hybrid in relation to a commercial corn hybrid (Con) on digestibility in wethers and on dry matter intake (DMI), milk yield and milk composition in dairy cows. Digestibility of crude fibre (CF), neutral detergent fibre (NDFom) and acid detergent fibre (ADFom) were higher for Bm (CF Con: 57.8%; Bm: 67.2%; NDFom Con: 56.8%; Bm: 64.8%; ADFom Con: 52.0%; Bm: 63.9%), but concentration of net energy for lactation did not differ (Con: 6.4 MJ/kg DM; Bm: 6.3 MJ/kg DM). A total of 64 lactating German Holstein cows were assigned to one of the two dietary treatments Con or Bm according to milk yield, lactation number, days in milk and live weight. In Trial 1, cows were fed a total mixed ration consisting of 50% corn silage (Con or Bm) and 50% concentrate on dry matter (DM) basis. In Trial 2, the same animals were fed the respective silage for ad libitum intake and 5.3 kg of concentrate DM per animal per day. In Trial 1, DMI and milk‐fat content were decreased significantly for the Bm‐treatment (DMI Con: 22.5 kg/day; Bm: 21.5 kg/day; milk fat Con: 3.8%; Bm: 3.3%). In Trial 2, milk yield and fat‐corrected milk (FCM) were increased significantly, whereas milk‐fat% was decreased significantly (milk yield Con: 25.8 kg/day; Bm: 29.4 kg/day; FCM Con: 27.2 kg/day; Bm: 29.6 kg/day; fat Con: 4.4%; Bm: 4.0%). Diets did not influence ruminal pH or temperature. Diets, furthermore, did not influence rumination in either trial. Additional research on digestibility and rumen fermentation should, however, be carried out using dairy cows at respective intake levels as trials with wethers cannot be transferred to high‐yielding ad libitum fed cows.     

Effect of distillers grains or corn supplementation frequency on forage intake and digestibility

Ten ruminally cannulated heifers (BW = 416 kg; SD = 24) were used to test the effect of the form and frequency of supplemental energy on forage DMI and digestibility. Five treatments were arranged in a replicated, 5 x 4 Latin rectangle (n = 8), and included no supplement (control), dry-rolled corn (DRC) fed daily, DRC fed on alternate days (DRC-A), dried distillers grains plus solubles (DDGS) fed daily, and DDGS fed on alternate days (DDGS-A). Supplements fed daily were fed at 0.40% of BW, whereas alternate day-fed supplements were fed at 0.80% of BW every other day. Chopped grass hay (8.2% CP) was fed to allow ad libitum DMI, and the intake pattern was measured. Control heifers had greater (P < 0.01) hay DMI than supplemented heifers (1.88 vs. 1.66% of BW daily, respectively), although total DMI was lower (P < 0.01) for control. Hay DMI did not differ (P = 0.45) between DRC and DDGS, and tended to be lower (P = 0.08) by heifers on DDGS-A and DRC-A than by heifers supplemented daily. Hay intake was lower (P < 0.01) on supplementation days for DDGS-A and DRC-A than on nonsupplemented days. Heifers in alternate-day treatments had fewer (P < 0.01) and larger (P < 0.01) meals and spent less (P < 0.01) time eating than those supplemented daily. Average rumen pH was greater (P = 0.05) for control than supplemented heifers (6.30 vs. 6.19). Control heifers had greater (P = 0.04) rates and extents of NDF disappearance than supplemented heifers. Rate of hay NDF disappearance was lower (P = 0.02) for DRC than for DDGS. Supplementation decreased hay DMI and changed digestion kinetics. Supplementation frequency affected amount and pattern of DMI. Rate of hay NDF disappearance was greater for DDGS than DRC.     

Effects of restricted versus conventional dietary adaptation on feedlot performance,carcass characteristics,site and extent of digestion,digesta kinetics,and ruminal metabolism

Three experiments were conducted to determine effects of restricting intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in grain over a period of 20 to 22 d on overall cattle performance, carcass characteristics, digestibility, digesta kinetics, and ruminal metabolism. In Exp. 1, 84 Angus x Hereford yearling steers (initial BW = 418 +/- 29.0 kg) were fed for 70 d. Restricting intake during adaptation had no effect (P > 0.10) on overall ADG:DMI, but decreased (P < 0.05) DMI compared with ad libitum access to adaptation diets, which resulted from differences during the initial 28 d of the experiment. In Exp. 2, 150 mixed crossbred steer calves (initial BW = 289 +/- 22.9 kg) were fed for an average of 173 d. Restricting intake decreased (P < 0.01) overall daily gain (1.51 vs 1.65 kg/d) and DMI (8.68 vs 9.15 kg/d) compared with ad libitum fed steers; however, ADG:DMI was not influenced (P > 0.10) by adaptation method. Experiment three used eight ruminally and duodenally fistulated steers (initial BW = 336 +/- 20 kg) in a completely random design. Total tract digestibility, digesta kinetics and ruminal metabolism were determined. Restricting intake reduced (P < 0.10) daily DMI variation from d 1 through 7, 8 through 14, and 22 through 28 compared with ad libitum feeding of three adaptation diets. Restricted steers had reduced (adaptation method x period interaction, P < 0.05) intakes and fecal excretions of ADF and greater OM digestibilities on d 4 through 7, 11 through 14, and 18 through 21. Digesta kinetics and ruminal metabolism were generally not affected (P > 0.10) by adaptation method. Our results suggest that restricted-feeding of the final diet as a means of dietary adaptation can be used in finishing cattle with few problems from acidosis or related intake variation. In light-weight steers (Exp. 2), disruptions in intake during the adaptation period might have resulted in restriction for an extended period, which decreased (P < 0.01) hot carcass weight compared with calves fed ad libitum. Effects of limit feeding during the initial 28 d of the feeding period on site and extent of digestion, digesta kinetics, and ruminal metabolism were minimal, supporting few differences in performance across the finishing period for yearling cattle.     

The effect of maize silage type on the performances and methane emission of dairy cattle

To examine whether type of maize silage is important for milk production performances, maize silage LG30224 (LG) was compared with Falkone (FA), the latter having a 4.0% points lower rumen NDF digestibility and 19 g/kg dry matter (DM) more starch. To bridge the lower energy content of FA, a third treatment was involved by adding maize meal (MM) in a ratio of 92/8 on DM (FA+MM). Maize and grass silage were fed ad libitum in a ratio of 65/35 on DM basis. Concentrates were supplemented individually to meet energy and protein requirements. The experiment was set up as a Latin square with three groups of nine Holstein cows during three periods of 3 weeks. In the last 2 weeks of each period, DM intake (DMI) and milk performances were measured. Each group included one cannulated cow to study effects on rumen fermentation. During the last 4 days of each period, two cows from each group were placed in gas exchange chambers to measure nutrient digestibility and methane production. Total DMI was higher (p < 0.05) for FA+MM (20.8 kg/day) than for FA (20.3 kg/day), while DMI for LG was intermediate (20.6 kg/day). Treatment did not affect milk production nor composition, whereas fat–protein‐corrected milk was higher for LG (30.5 kg/day) and FA+MM (30.3 kg/day) than for FA (29.9 kg/day). The ration did not affect pH nor volatile fatty acid composition in the rumen. Further, total tract digestibility of OM, crude protein, NDF and starch did not differ among treatments. The ration with LG gave higher methane production per day and per kg NDF intake than both rations with FA, but the difference was not significant when expressed per kg DMI or FPCM. Thus, maize silage type is of little importance for milk production if energy and physical structure requirements are met.     

不同锰元素含量日粮对犊牛生长性能和粪尿排泄指标的影响研究

日粮1%预混料减少120mg/kg锰元素时,30天犊牛累积生长显著高于对照组（P < 0.05）,说明锰元素与犊牛的生长性能确有明显影响;但是日粮中不同的锰元素对于犊牛体尺指标均没有显著影响（P > 0.05）,说明微量元素锰对于犊牛体尺性能影响不大。而且,研究发现日粮1%预混料减少60mg/kg、120mg/kg和240mg/kg锰元素均可以适当提高犊牛粪便氮磷的表观消化率,降低犊牛多种元素的排放,其中日粮1%预混料减少240mg/kg锰元素时的氮磷消化率最高,而且可以有效降低犊牛粪氮、粪铜和粪锌的排放量、30天的尿氮排放量,效果最好。     

Effects of supplementary probiotics to two different diets on dry matter intake, daily gain, digestibility, ruminal pH, and fecal microbial populations and metabolites in ewes

To study the effects of supplementary probiotics on dry matter intake (DMI), daily gain (DG), digestibility, ruminal pH, and fecal microbial populations and metabolites in ruminants, two reversal trials were conducted by using four Suffolk ewes fitted with rumen cannula. The ewes were fed with oat hay and with concentrate and oat hay in the ratio of 60 : 40 in experiments 1 and 2, respectively. The ewes in the treatment groups were supplemented with 10 g/day/head probiotics for 49 days. Fresh fecal samples were collected to measure microbial populations and metabolites. On days 43–47 total feces was collected to measure digestibility, and on the days 48 and 49 ruminal pH was measured. No significant difference of DMI, DG, dry matter digestibility, and ruminal pH was observed between the control and treatment groups. The probiotics treatment tended to increase crude fiber (P = 0.11) and organic cell wall digestibility (P = 0.18). In the final week, probiotics treatment significantly increased the fecal population of Bacilli (P < 0.05) and mold (P < 0.01) in experiment 1 and 2, respectively. No significant difference of fecal VFA and ammonia concentrations between the control and treatment groups was observed. The supplementary probiotics changed population of some microbial strains in the feces and possibly the large intestine of ewes.     

An evaluation of anthelmintic properties,assessed using faecal nematode egg counts,of New Zealand native flax (Phormium tenax)

AIM: To investigate the anthelmintic properties of New Zealand native flax (Phormium tenax) for cattle, using a faecal egg count reduction test (FECRT).

METHODS: Twenty-six heifer calves with high (>300 epg) faecal nematode egg counts (FEC) were paired into two groups and fed either chopped flax leaves ad libitum, or barley straw at an equivalent dry matter (DM) rate, from Day 0–7; all were supplemented with 1.5 kg/head/day cereal feed supplement. On Days 8–10, all heifers were fed a common diet of 3.5 kg DM/ head/day barley straw and 1.5 kg/head/day cereal feed supplement. Heifers were weighed and faecal samples were collected on Days —6, 0, 7, and 10; samples were analysed in triplicate for FEC. The nutritive value of the flax and straw was analysed.

RESULTS: Both the flax and straw had low dry matter digestibility (DMD) and protein content. Although the flax-fed claves grew more than the controls, this may have been related to gut fill. Total daily faecal egg output was similar for flax and straw groups on Day 7 (14.7 vs 15.0 x 10⁶ eggs/day, respectively) and Day 10 (14.9 vs 15.1 x 10⁶ eggs/day, respectively). There was no difference in the change in FEC with time between the calves fed flax or straw diets.

CONCLUSION: Consumption of flax leaves did not reduce FEC in calves with a mixed nematode infection.     

饲喂模式对猪生长性能、养分消化率和肠道微生物组成的影响

本试验旨在探究不同饲喂模式对猪生长性能、养分消化率和肠道微生物组成的影响。选择120头平均初始体重(26.0±0.4)kg的生长猪(公、母各半),按体重和性别随机分为自由采食组(FA)和限制饲喂频率组(每天饲喂3次,M3),每个处理10个重复,每个重复6头猪,试验期共28 d。结果表明:M3组平均日采食量和耗料增重比均显著低于FA组(P<0.05);饲喂模式的改变对养分表观全肠道消化率无显著影响(P>0.05);M3组血浆尿素氮和游离脂肪酸水平显著低于FA组(P<0.05),而胰岛素水平显著高于FA组(P<0.05);饲喂模式对猪粪便微生物组成有一定影响,在门水平上,M3组拟杆菌门丰度显著低于FA组(P<0.05),柔膜菌门和疣微菌门丰度显著高于FA组(P<0.05);在属水平上,M3组Prevotellaceae_UCG-003、Ruminococcaceae_UCG-010、Ruminococcaceae_NK4A214_group、Rikenellaceae_RC9_gut_group和Coprostanoligenes_group的丰度显著高于FA组(P <0.05),而Selenomonas、Roseburia、Prevotella_2、Prevotella_7、Prevotella_9、Anaerovibrio和Alloprevotella的丰度显著低于FA组(P<0.05)。综上,饲喂模式对生长猪养分消化率无显著影响,限制饲喂频率可改变肠道微生物组成并改善生长猪饲料报酬。