首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 453 毫秒
1.
Thirty-four Holstein cows, 18 primiparous and 16 multiparous, were used to determine the effects of supplemental Cr on carbohydrate and lipid metabolism during the transition period. From approximately 3 wk prior to anticipated calving date until parturition, Cr-treated cows were given 51 mg Cr picolinate via a gelatin capsule bolus three times weekly, equivalent to an average daily intake of approximately 2 ppm Cr. Control cows were given empty gelatin capsules. All cows were fed total mixed rations, with one ration fed to dry cows, a second to lactating cows for wk 1 of postpartum (transition), and a third to lactating cows thereafter. Blood samples were collected via jugular venipuncture at 1, 2, and 3 wk prior to anticipated calving date as well as immediately following calving, 3 d post calving, and 1, 2, and 3 wk post calving. Samples were analyzed for glucose, insulin, and nonesterified fatty acids (NEFA). Within 1 wk prior to calving, a frequently sampled intravenous glucose tolerance test was performed, and blood plasma samples were analyzed for concentrations of glucose and insulin. Plasma glucose response to the frequently sampled intravenous glucose tolerance test was evaluated by calculating the half-life and fractional turnover rate for the period from 2 to 19 min after glucose infusion. Supplemental Cr did not affect circulating concentrations of glucose, insulin, or NEFA (P>0.1). Plasma NEFA concentrations were greater in primiparous cows (P<0.01) throughout the experiment, with the difference being most apparent during the 3 wk postpartum. Glucose concentrations reached a greater peak at time of calving in primiparous cows than in multiparous cows (P=0.07). There was an increase in glucose clearance rate (P=0.06) and a trend toward decreased glucose half-life (P<0.1) in primiparous cows supplemented with Cr. Insulin peak concentrations were unaffected by treatment or parity (P>0.1). Data suggest that Cr supplementation may alter carbohydrate metabolism in primiparous cows during the transition period.  相似文献   

2.
丙酸钙对泌乳早期奶牛泌乳性能和代谢产物的影响   总被引：1，自引：0，他引：1  
选用32头经产奶牛,根据泌乳期、上个泌乳期305 d产奶量和预产期,采用随机区组设计分为4组,对照组饲喂基础日粮,处理1、2、3组分别在基础日粮基础上添加丙酸钙100、200、300 g/d.结果显示,日粮添加丙酸钙对奶牛的采食量、乳脂率、乳蛋白率、乳糖率和乳干物质率无显著影响,200、300 g/d组产奶量和饲料转化效率显著高于对照组(P<0.05).200、300 g/d组血浆葡萄糖和胰岛素浓度显著高于对照组(P<0.05),而血浆游离脂肪酸和β-羟丁酸浓度显著低于对照组(P<0.05);200、300 g/d组尿酮浓度显著低于对照组和100 g/d组(P<0.05).试验结果表明,丙酸钙适宜添加量为200 g/d.  相似文献   

3.
Twenty-one multiparous dairy cows were fed concentrates containing three levels (119, 154 and 191 g/kg DM) of crude protein (CP) during the first ten weeks of lactation. Part of the grain and molassed sugar beat pulp was substituted with 0% (RSM0), 15% (RSM15) or 30% (RSM30) repeseed meal. Wilted grass silage was fed ad libitum after calving. The average response between RSM0 and RSM15 was +1.66 kg milk/d per percentage unit change in concentrate CP content. No further response occurred between RSM15 and RSM30. The positive effect of RSM inclusion was seen throughout the experimental period and was associated with increased plasma non esterified fatty acids (NEFA) and decreased plasma insulin concentration one week after calving, and higher efficiency of metabolisable energy utilisation for milk production. Digestibility of the diet remained unaffected. Milk and plasma urea tended to increase with RSM30 indicating excessive supply of rumen degradable protein. Because of the limited potential of cows to compensate for a deficit in feed protein supply by mobilising tissue protein, a substantial milk yield response can be achieved with a moderate level of protein supplementation during early lactation.  相似文献   

4.
The objective of this study was to determine the effect of partial replacement of barley grain with beet pulp (BP) on dry matter intake (DMI), ruminal fermentation, plasma concentration of metabolites and milk yield of transition dairy cows. Twenty‐four multiparous Holstein cows [735 ± 26 kg of body weights and 3.5 ± 0.05 of body condition score (BCS)] were used in a randomized complete block design. Cows were assigned randomly on day 28 relative to expected parturition date to one of three treatments containing (i) 0% BP, (ii) 25% BP or (iii) 50% BP substituted for barley grain on a DM basis. During the pre‐partum period, DMI and energy intake were greater (P < 0.01) in cows fed the BP diet compared with cows fed the barley grain diet. During the post‐partum period, substituting BP for barley grain caused a response in DMI and energy intake, with the highest amount for the 25% BP diet and lowest for the 50% BP diet (P < 0.01). Milk yield was lowest (P < 0.01) for 50% BP diet than the other treatments. During the post‐partum period, cows fed the 50% BP diets had greater rumen pH, molar proportion of butyrate and acetate: propionate ratio (P < 0.01) in the rumen compared with cows fed the 0% BP diets. In addition, cows fed the BP diets had greater (P < 0.01) plasma β‐hydroxybutyrate and lower plasma glucose (P < 0.05) and blood urinary nitrogen (BUN) (P < 0.01) concentrations than cows fed the barley grain diets. Results showed that substituting BP for barley grain was effective in increasing DMI, but it did not have a significant effect on net energy balance during the post‐partum period. However, replacing BP for barley grain at 50% had adverse effects on DMI, milk yield and metabolic status, as indicated by key blood metabolite concentrations.  相似文献   

5.
将围产期健康乳牛30头随机分为3组，分别于产前第28d开始饲喂标准日粮（能量摄入i00％组）、标准日粮增加20％的日粮（能量摄入120％组）和标准日粮减少20％的日粮（能量摄入80％组），产后备组乳牛均饲喂标准泌乳日粮，至产后第56d结束，观察干奶期不同能量摄入水平对围产期健康乳牛血液葡萄糖、胰高血糖素和胰岛素浓度的影响。结果表明，产前低能饲喂可以增加围产期乳牛血浆葡萄糖浓度，干奶期不同能量摄入水平对围产期健康乳牛血液葡萄糖、胰高血糖素和胰岛素浓度起重要调节作用。  相似文献   

6.
Wheat grain (WG) is a unique cereal rich in easily fermentable starch and low in cation–anion difference (e.g. 5.3 mEq/100 g). The controlled prepartal dietary inclusion of WG, thus, has the potential to ease adapting the rumen microbes and papillae to the high‐starch lactation diets, stimulate feed intake, reduce hypocalcaemia by reducing extracellular alkalinity and a moderate induction of bone resorption, and improve milk yield in periparturient cows. The primary objective was to determine the effects of prepartal feeding of WG compared to barley grain plus wheat bran on metabolic and productive criteria in periparturient Holstein cows. Twenty‐four dry cows and 16 pregnant heifers were blocked based on parity and projected calving date and fed a prepartal diet containing either (i) ground WG (18% on a dry matter basis) or (ii) a conventional diet with ground barley grain and wheat bran or control diet, from 28‐day prepartum until parturition. All cows were fed the control diet during 21‐day postpartum. Prepartal dietary inclusion of WG increased prepartum feed intake, elevated blood glucose and attenuated hypocalcaemia at 7‐day prepartum and 1‐day postpartum, reduced urine pH, and increased milk fat percent and yield. Blood proteins at 7‐day prepartum were higher and placenta tended to be expelled sooner in WG‐fed cows than in other cows. Treatments did not affect milk protein, changes in body condition score; total time spent eating, ruminating and chewing; blood levels of urea nitrogen, cholesterol, and phosphorous, fecal pH, and calving difficulty. Therefore, the prepartal dietary use of WG proved effective in the simultaneous improvement of calcium and energy states, and thereby, in easing the metabolic transition from gestation into lactation in Holstein cows.  相似文献   

7.
Seven nonlactating mature Angus cows (4 to 10 yr old) were used to examine the effects of fish meal supplementation on plasma and endometrial fatty acid composition. Cows were fed a corn silage-based diet supplemented with either fish meal, a rich source of the n-3 fatty acids, eicosapentaenoate and docosahexaenoate (n = 3; 5.1% of dietary DM), or corn gluten meal (n = 4; 8.5% of dietary DM) for approximately 64 d. Cows were given 25 mg of PGF2alpha (i.m.) on d 11 and 25 of supplementation to synchronize estrous cycles. On d 18 postestrus of the second estrous cycle, cows were slaughtered, and caruncular endometrium was dissected from uteri immediately after slaughter. Jugular blood samples were collected immediately before supplementation was initiated (d 0) and at 7-d intervals for 35 d of the study. Plasma eicosapentaenoic and docosahexaenoic acids did not differ between treatment groups on d 0 (P > 0.10); however, these fatty acids were greater in cows supplemented with fish meal over the first 35 d of supplementation compared with cows supplemented with corn gluten meal (P < 0.05). Endometrial docosahexaenoic acid did not differ (P = 0.12), whereas eicosapentaenoic acid was greater (P < 0.05) in cows supplemented with fish meal than in cows supplemented with corn gluten meal. These results indicate that dietary fish meal alters plasma and endometrial n-3 fatty acid composition in beef cows.  相似文献   

8.
Trials were conducted to evaluate effects of a fermentation extract of Aspergillus oryzae (AO) on milk production and composition, diet digestibility, and rectal temperature changes in lactating dairy cows. Treatments were incorporated as a top dressing at the morning feeding and consisted of control (90 g/d of ground sorghum) or AO (3 g of culture + 87 g of ground sorghum daily). Twenty-four mid-lactation Holstein cows were paired for production in Lactation Trial 1 (LT-1). In Lactation Trial 2 (LT-2), 46 cows (20 primiparous and 26 multiparous) in early lactation were used. Trials lasted 12 wk. In LT-1, AO supplementation increased milk yields only at 2 (P less than .05) and 8 wk (P less than .10) of treatment. Rectal temperatures were lower (P less than .05) for cows fed AO for 4 of 10 readings made during summer. Supplementation of AO culture in LT-2 (early lactation cows) increased milk production and feed efficiency (P less than .05). Inner ear temperatures tended to be lower (P less than .11) for cows fed AO. Digestion trials, conducted at the end of lactation trials, used Cr2O3 as an indigestible marker. In Digestion Trial 1, digestibilities were not significantly (P greater than .10) affected by AO supplementation. However, in Digestion Trial 2, AO increased (P less than .05) digestibilities of DM, OM, CP, NDF, and ADF. Length and number of meals were not affected (P greater than .10) by feeding AO. In summary, milk yields, efficiency of milk production, and nutrient digestibilities were higher for early lactation cows fed a high-concentrate diet supplemented with 3 g of AO/d. Mid-lactation cows fed a lower-energy diet were less responsive to AO than early lactation cows, though similar trends were shown.  相似文献   

9.
One hundred and twenty early lactating Holstein dairy cows were assigned to investigate the effect of dietary chromium (Cr) supplementation (0 or 6 mg Cr/head/day from organic preparation) on the productive and reproductive performance as well as on some blood serum parameters under heat stress (35–40 °C). Cows received treatment from 3 weeks pre‐partum through 12 weeks post‐partum. Chromium supplemented diet had lower body weight loss and improved dry matter intake with consequent reduction in the energy balance deficits during the first period after calving when compared with the control group. Chromium supplementation increased (p < 0.05) milk yield by 6.7%, 12.3% and 16.5% at 4, 8 and 12 weeks post‐partum, respectively, whereas milk composition and milk to feed ratio were unaffected (p > 0.05) when compared with the control. Moreover, dietary Cr supplementation had no effect (p > 0.05) on blood serum glucose, calcium and phosphorus concentrations. A reduction (p < 0.05) of non‐esterified fatty acids at 1 week pre‐partum, 2 and 4 weeks post‐partum was also observed. Serum insulin concentration increased whereas cortisol concentration decreased, when compared with the control group, throughout the whole experimental period. Also Cr supplementation showed a trend towards improving reproductive performance as indicated by increased percentage of pregnant cows in the first 28 days of breeding. It could be concluded that dietary Cr supplementation at level of 6 mg/head/day may offer a potential protective management practice to lessen the effect of heat stress in dairy cattle.  相似文献   

10.
Two experiments were conducted to quantify the impact on forage use and performance of varying supplementation frequency of cattle consuming forage diets across a range of frequencies. In both experiments, a common supplement was used that contained a relatively high concentration of CP (43%) and was fed at the following frequencies: 1) 2 d/wk; 2) 3 d/wk; 3) 5 d/wk; and 4) 7 d/wk. In Exp. 1, 120 Hereford x Angus cows (BW = 537 kg) grazing winter tallgrass-prairie range were supplemented at the various frequencies from December 7 until calving (average calving date = 3/7/99). All treatments provided the same quantity of supplement on a weekly basis (12.74 kg, as-fed) but divided the amount delivered on a given day equally among the number of supplementation events for that treatment. Less BW was lost from December 7 through calving (linear effect, P = 0.02) as frequency of supplementation increased, but the magnitude of difference in weight change was relatively small. Body condition responded similarly through early February (linear effect, P = 0.02), although treatment effects were not as distinct at calving (cubic effect, P = 0.11). In Exp. 2, 16 ruminally fistulated Hereford x Angus steers (BW = 257 kg) were blocked by weight and assigned to one of the four frequencies of supplementation. Steers were offered tallgrass prairie hay (73.5% NDF, 4.8% CP) ad libitum and were supplemented at a rate (relative to BW) similar to that of the cows in Exp. 1. Increasing frequency of supplementation increased (linear effect, P < or = 0.02) forage OM intake, OM and NDF digestion, and digestible OM intake. However, the most prominent differences in forage OM intake tended (cubic effect, P = 0.07) to occur with the two extreme frequencies of supplementation. In conclusion, forage use was improved with an increased frequency of supplementation, but the impact on performance is not likely to be large unless extreme differences in frequency occur.  相似文献   

11.
This study investigated how supplementation of the diet of dairy cows with trace minerals (zinc, manganese, copper and cobalt) affected kinematic gait parameters and lactation performance. Eight Holstein cows were divided into two groups, with each group receiving a different dietary treatment (control diet, or control diet supplemented with trace minerals) in a two‐period crossover design. Kinematic gait parameters were calculated by using image analysis software. Compared to cows fed the control diet, cows that received the trace mineral‐supplemented diet exhibited significantly increased walking and stepping rates, and had a shorter stance duration. Feed intake and milk production increased in cows fed the trace mineral‐supplemented diet compared with control groups. The plasma manganese concentration was not different in control and experimental cows. In contrast, cobalt was only detected in the plasma of cows fed the supplemented diet. These results provide the first evidence that trace mineral supplementation of the diet of dairy cows affects locomotion, and that the associated gait changes can be detected by using kinematic gait analysis. Moreover, trace mineral supplementation improved milk production and only minimally altered blood and physiological parameters in dairy cows.  相似文献   

12.
Twenty multiparous and four primigravid Holstein cows were utilized in a completely random design to characterize the influence of decreasing prepartum dietary cation-anion difference (DCAD) from +388 to +183 meq/kg diet on DMI, prepartum blood profiles, and postpartum milk yield and composition of dairy cows grazed during the prepartum period. Treatments began on wk −4 prepartum, continued through calving, and consisted of 1) pasture and grain pellet without anionic salts (control; +388 meq/kg) or 2) pasture and grain pellet containing anionic salts (AS) (+183 meq/kg). Prepartum cows were rotationally grazed as a single group and individually fed pellets twice daily at a rate of 0.5% of BW/d. Blood and urine samples were collected on wk −4, −2.5, and −1 prepartum and analyzed for Ca, Mg, K, Na, and Cl concentrations. Urine samples were also analyzed for pH. Chromic oxide was dosed twice daily during the last 4 wk of gestation and again for 10 d during wk 4 and 12 postpartum for estimation of intake. Cows calved on pasture and were then integrated into the regular milking herd and fed a total mixed ration (TMR). Daily milk yield and weekly milk samples were collected through wk 14 of lactation. Prepartum and postpartum DMI, milk yield and composition, and plasma minerals were not affected by treatment. No clinical cases of milk fever were observed for either treatment group. Reducing prepartum DCAD from +388 to +183 meq/kg DM did not improve prepartum blood profiles or postpartum milk yield or composition; therefore, this type of supplementation was not economical.  相似文献   

13.
One hundred forty-three crossbred, fall-calving first-calf heifers were used to determine the effects of two levels of energy and two levels of lasalocid on cow-calf productivity. Diets fed for approximately 110 d prepartum were calculated to provide a daily intake of 15.3 (LE) or 18.0 (HE) Mcal ME; diets fed for approximately 130 d postpartum were calculated to provide a daily intake of 17.8 (LE) or 21.0 (HE) Mcal ME. Two supplements were fed with each energy level to provide a calculated 0 (C) or 200 mg.hd-1.d-1 lasalocid (L). Heifers fed HE gained .06 kg more (P = .08) per day prepartum than LE heifers. There was an interaction (P less than .05) between treatment and prepartum days on trial for heifer weight approximately 2 wk prepartum and body condition at calving. Energy had no effect on heifer weight at 2 wk prepartum or condition score at calving when estimated and compared at 90 d on trial. However, regression estimates for 130 d on trial showed that HE heifers would have been 19 kg heavier (P less than .001) and would have had .4 unit higher condition score (P less than .01) than LE heifers. Energy and lasalocid had no effect (P greater than .05) on hip height or pelvic area at calving or on calf birth weight, calving ease score or gestation length. Cows fed HE weighed 17 kg more (P less than .05) and had .5 unit higher (P less than .001) condition score than LE cows at approximately 130 d postpartum. Lasalocid had little effect on postpartum changes in weight or body condition. Lasalocid supplementation to the LE diet tended to increase milk production and calf weight, whereas supplementation to the HE diet did not. Feeding the LE diet decreased (P less than .05) cycling activity by 18 percentage points and decreased (P less than .01) overall pregnancy rate by 25 percentage points. Lasalocid had no influence on reproductive performance.  相似文献   

14.
Dry cow diets based on grassland forage from intensive production contain high amounts of K and could be responsible for a reduced ability to maintain Ca homoeostasis. The aim of this study was to determine whether a moderate anionic salt supplementation to a forage‐based pre‐calving diet with varying native K content affects the mineral and acid–base status in transition cows. Twenty‐four dry and pregnant Holstein cows, without antecedent episodes of clinical hypocalcemia, were assigned to two diets during the last 4 weeks before estimated calving date. Twelve cows were fed a hay‐based diet low in K (18 g K/kg DM), and 12, a hay‐based diet high in K (35 g K/kg DM). Within each diet, six cows received anionic salts during the last 2 weeks before the estimated calving day. After calving, all cows received the high K diet ad libitum. Blood samples were taken daily from day 11 pre‐partum to day 5 post‐partum. Urine samples were taken on days 7 and 2 pre‐partum and on day 2 post‐partum. The anionic salt did not alter feed intake during the pre‐partum period. Serum Ca was not influenced by the dietary treatments. Feeding pre‐partum diets with low K concentrations induced a reduced metabolic alkalotic charge, as indicated by reduced pre‐partum urinary base–acid quotient. Transition cows fed the low K diet including anionic salts induced a mild metabolic acidosis before calving, as indicated by higher urinary Ca, lower urinary pH and net acid–base excretion. Although serum Ca during the post‐partum period was not affected by dietary treatment, feeding a low K diet moderately supplemented with anionic salts to reach a dietary cation–anion difference close to zero permitted to obtain a metabolic response in periparturient cows without altering the dry matter intake.  相似文献   

15.
The effect of Se supplementation before or after calving on Se status in deficient cows and their calves was studied using 72 beef cows in two experiments. In Exp. 1, cows calving in February or March 1997 were supplemented orally for 15 d in late pregnancy with 13.0, 32.5, or 45.5 mg of Se/d as sodium selenite. Glutathione peroxidase (GSH-Px) activities were measured in red blood cells (RBC) or plasma of cows and calves at d 15 and between d 17 and 88 after calving. In Exp. 2, cows calving in January 1997 were supplemented orally with .0, 13.0, or 32.5 mg of Se/d for 15 d postpartum, and calves were injected with 1.38 mg of Se when 2 d old and at an average age of 49 d. The GSH-Px activities were measured in 30-d-old calves and in cows and calves between d 77 and 115 after calving. In both experiments, Se supplementation resulted in adequate Se status for the dams. The increase in RBC GSH-Px activity was faster with 45.5 mg of Se/d, and GSH-Px activities remained high for up to 98 d after the end of supplementation. The improvement in Se status in calves as a result of maternal supplementation was greater in Exp. 1 than in Exp. 2, suggesting that the placental transfer of Se is more efficient than milk transfer. Prepartum oral Se supplementation of deficient beef cows with 13.0 mg of Se/d for 15 d allowed adequate Se status of dams and calves, and 45.5 mg of Se/d resulted in a faster improvement of Se status. Parenteral administration of 1.38 mg of Se to newborn calves did not sustain normal Se status in calves issued from deficient cows.  相似文献   

16.
研究过瘤胃葡萄糖对泌乳奶牛产奶量及乳成分的影响。试验选用20头中国荷斯坦奶牛,按照胎次、体况及产奶量随机分成A、B两组(n=10)。A组牛为对照组,饲喂奶牛场原有基础日粮+2%脂肪粉;B组为试验组,饲喂基础+2%过瘤胃葡萄糖。结果表明,与A对照组相比较,添加过瘤胃葡萄糖后显著增加了奶牛产奶量(P<0.01),平均提高8.71kg/d;过瘤胃葡萄糖对乳脂率、乳蛋白率及乳中干物质含量均无明显变化,差异不显著(P>0.05)。在试验条件下,过瘤胃葡萄糖可显著提高泌乳奶牛产奶量。  相似文献   

17.
In a model experiment, Holstein-Friesian dairy cows were fed on a corn-silage-based diet supplemented with 11.75 MJ NE1 per day of calcium soaps of palm oil fatty acids (CAS) or hydrogenated triglyceride (HTG) or without fat supplementation (control). All diets were fed to the cows over a period from 21 +/- 3 days (d) prior to the expected calving to d 100 +/- 5 postpartum. On d 25 (basal sample) and d 14 prepartum as well as on d 5 and 25 postpartum liver samples were collected by percutaneous biopsy. Total lipid content, fatty acid composition and glycogen of liver tissues were determined. At d 5 postpartum, both control and CAS cows had higher liver lipid (P < 0.05) and lower glycogen (P < 0.05) concentrations than cows in the HTG group. No significant (P < 0.05) differences were detected in liver fat content among the groups at d 14 prepartum or d 25 postpartum. The glycogen concentration slightly decreased in the liver of cows in each treatment group from d 14 prepartum to d 5 postpartum; however, this decrease was more intensive in both the control and CAS groups than in the HTG group. The variations in liver lipid concentrations were accompanied by significant changes in the proportion of C16:0, C16:1n-7, C18:0, C18:1n-9, C18:2n-6 and C20:4n-6 fatty acids in the liver lipids. The results show that HTG supplementation exerted more advantageous effects on liver lipid and glycogen metabolism than did CAS supplementation.  相似文献   

18.
This study investigated the effects of feeding barley grain treated with lactic acid (LA) and heat on the profile of plasma metabolites related to carbohydrate and lipid metabolism and variables related to rumen health and acute phase response. Eight primiparous rumen-fistulated lactating Holstein cows were randomly assigned, in a crossover design, to 1 of the 2 dietary treatments consisting of 32% (DM basis) rolled barley grain steeped in an equal quantity of either tap water alone (CTR) or a 1.0% LA solution and heated at 55°C for 48 h (LAH). Each experimental period was 21 d, with the last 10 d used for measurements. Blood samples were collected on d 1, 3, 5, 7, 9, and 11 before the morning feeding and on the last day of each period at 0, 2, 4, 6, 8, 10, and 12 h postfeeding to measure glucose, lactate, cholesterol, beta-hydroxybutyrate (BHBA), NEFA, haptoglobin (Hp), serum amyloid A (SAA), and tumor necrosis factor-alpha (TNF-α). Also, rumen samples were collected on d 1, 5, and 11 as well as at 0, 4, 8, and 12 h postfeeding on the last day of each period for measuring the concentration of rumen endotoxin. Results of the day-to-day analysis indicated that cows fed the LAH diet had reduced preprandial concentrations of rumen endotoxin (472 vs. 793 ng/mL; P < 0.01) and cholesterol and greater lactate in the plasma; however, treatment had no effect on plasma Hp and TNF-α (P > 0.10). Postprandial responses showed that the LAH diet tended to decrease the concentration of SAA (4.67 vs. 8.50 μg/mL; P = 0.06). Also, there was a treatment by time interaction for rumen endotoxin (P < 0.01), suggesting a role for both the treatment and the time of sampling on this variable. Furthermore, greater concentration of BHBA and a tendency for greater NEFA and reduced concentrations of plasma glucose were observed in cows fed the LAH diet. In conclusion, results indicated that feeding dairy cows barley grain steeped in 1.0% LA and treated with heat modulated the profile of plasma metabolites and acute phase response.  相似文献   

19.
Twelve multiparous Holstein cows at 72 +/- 20 days in milk were used in a switch-back design with 14-d periods to determine the effect of replacing barley grain into a dairy total mixed ration with micronized or raw flaxseed on nutrient digestibility, milk yield, milk composition. Total mixed diets were (DM basis) 50% barley silage, 50% concentrate mix mainly rolled barley grain and canola meal. Diets were supplemented with 1 kg raw (RF) or micronized (MF) flaxseed to substitute 1 kg of rolled barley grain (C). Neutral detergent fibre, ADF and CP digestibility of the diets were not significantly affected by supplementation; however, calcium digestibility was reduced by 62% and 46% when raw and micronized flax were fed, respectively. Milk yield (38.3, 39.6, and 38.4 kg/d for diets C, RF and MF, respectively) was similar for all diets. Milk fat (3.50, 3.48, and 3.52%) and protein (3.31, 3.34, and 3.31%) for diets C, RF and MF, respectively, were not affected by treatment diets. Concentrations of c9, t11 conjugated linoleic acid (CLA; 0.51, 0.72 and 0.76 g/100 g fatty acids) in milk fat increased (P<0.05) similarly among the two flaxseed supplemented diets. The RF and MF diets significantly increased the C18:1, C18:1 trans-11, C18:2 cis-9, cis-12 and C18:3 in milk fat however, C12:0, C14:0 and C16:0 were significantly reduced compared with control. Replacing barley grain with flaxseed in the diet of lactating cows increased the beneficial fatty acids in milk without depressing nutrient digestibility. Micronization of flaxseed did not reveal any advantage over raw flaxseed.  相似文献   

20.
The effects of copper supplementation on the copper status of 40 late-pregnant Aubrac beef cows grazing a copper-deficient pasture and later fed a marginally deficient diet were studied for five months. They were divided into four equal groups; the control group received no copper supplement, groups 1 and 2 received copper as copper sulphate at 10 and 30 mg/kg of diet dry matter (DM), respectively, for five months, and group 3 received 120 mg/kg of diet dry matter for 10 days. Plasma copper concentration and the activity of erythrocyte superoxide dismutase (eSOD) were measured at the beginning of the experiment, in the cows and calves during weeks 1 and 3 after calving, and in the calves before they were turned out to pasture at a mean (sd) age of 51 (26) days. In spite of the low dietary copper content (4.2 mg/kg of DM), the plasma copper concentration of the control cows increased during the winter. All the copper supplements resulted in normal and similar plasma copper concentrations in the cows after calving, but the concentration decreased slightly between weeks 1 and 3 after calving in the group supplemented for 10 days. The treatments did not affect the eSOD of the cows. The calves born to the four groups showed the same patterns of plasma copper and eSOD. Compared with the cows, the calves had low plasma copper concentrations at week 1 and values in the normal range at week 3; their eSOD was high at weeks 1 and 3 but decreased after week 3.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号