不同类型日粮添加酶制剂对蛋品质和蛋鸭生产性能的影响

选用500羽50周龄金定蛋鸭,研究不同类型日粮添加酶制剂对蛋鸭生产性能和蛋品质的影响.试验随机分成2组,分别设为对照组(玉米-豆粕型+植酸酶500 FTU/kg)和试验组(小麦-豆粕型+植酸酶500 FTU/kg+木聚糖酶),每组5个重复,每个重复50羽.研究结果表明,试验组与对照组相比,平均产蛋率提高6.6%(P>0.05),平均蛋重提高1.6%(P>0.05),料蛋比降低12.4%(P>0.05);蛋品质方面,试验组和对照组在蛋壳重、蛋形指数、蛋壳色泽、蛋壳强度、蛋白高度、哈氏单位均差异不显著(P>0.05);蛋黄重与蛋黄色泽均差异极显著(P<0.01).结论:用小麦替代日粮中的全部玉米并添加植酸酶和木聚糖酶饲喂蛋鸭,可以提高蛋鸭生产性能,增加经济效益.     

葎草-麦秸碾青料对肉牛生长性能和屠宰性状的影响

探讨葎草-麦秸碾青料对肉牛生长性能和屠宰性状的影响.对照组饲喂基础日粮,基础日粮中粗饲料为麦秸-苜蓿草,试验组使用葎草-麦秸碾青料分别替代20％、40％、60％的麦秸-苜蓿型粗饲料.结果表明:与对照组相比,40％、60％律草-麦秸碾青料组肉牛头均日增重有所提高(P＞0.05),眼肌面积分别提高了18.2％和6.4％.与对照组相比,40％葎草-麦秸碾青料组肌肉粗蛋白质含量提高7.3％,粗脂肪含量降低5.3％;60％葎草-麦秸碾青料组肌肉粗脂肪含量降低了6.1％.40％葎草-麦秸碾青料替代麦秸-苜蓿草料较适宜.     

发酵饲料对断奶仔猪生产性能、血液生化指标和饲料养分表观消化率的影响

选用28日龄断奶的三元杂交(杜×长×大)仔猪60头,随机分为饲喂发酵饲料的试验组和不合发酵料的对照组:每个处理3个重复,每个重复10头猪.试验结束前连续收集3天粪便,测定饲料养分的表观消化率;试验结束时前腔静脉采血,测定血清生化指标.结果:试验组比对照组显著降低了料肉比和腹泻指数(P＜0.05),日增重提高,但显著不差异(P＞0.05);血清碱性磷酸酶显著提高(P＜0.05),而血清尿素氮、总蛋白、白蛋白、谷丙转氨酶均没有显著变化(P＞0.05).饲料养分的表观消化率(CTTAD)试验组日粮磷的消化率显著提高(P＜0.05),粗脂肪消化率显著下降(P＜0.05),粗蛋白和钙的消化率提高,但无显著差异(P＞0.05).结果表明,发酵饲料有利于提高仔猪的生长性能和饲料养分的表观消化率,对降低仔猪断奶应激性腹泻有较好效果.     

α-硫辛酸对育肥猪生产性能和抗氧化功能的影响

研究日粮中添加α-硫辛酸对肥育猪生产性能和抗氧化功能的影响.对照组饲喂基础日粮,试验组在基础日粮中分别添加300、600和900 mg/kg的旷硫辛酸,试验期28 d.结果表明:与对照组相比,添加600、900 mg/kgα-硫辛酸降低了平均日增重(P＜0.05)和平均日采食量(P＜0.01),而各组料重比差异均不显著(P＞0.05);900mg/kgα-硫辛酸组总抗氧化能力增加显著(P＜0.05),谷胱甘肽过氧化物酶活性极显著增强(P＜0.01).α-硫辛酸添加组血清中丙二醛含量均显著降低(P＜0.05).α-硫辛酸的适宜添加水平为600 mg/kg.     

喹赛多对肉用齐卡兔生产性能的影响

选择30日龄体重基本一致的齐卡兔60只(公、母各半),随机分成5组,其中对照组饲喂基础日粮,试验组分别在基础日粮中添加喹赛多50 mg/kg、喹赛多100 mg/kg、喹乙醇50 mg/kg和喹乙醇100 mg/kg,进行为期60 d的饲养试验;研究喹赛多和喹乙醇对肉用齐卡兔生产性能的影响.结果表明:试验组与对照组相比,平均日增重提高显著(P＜0.05);100 mg/kg喹赛多组与对照组日耗料量相当,而其它各组日耗料量则显著低于对照组(P＜0.05);试验组与对照组相比料重比降低显著(P＜0.05),但试验组间差异不显著(P＞0.05);试验组肉兔腹泻率降低.喹赛多组优于喹乙醇组,其适宜添加量为100 mg/kg.     

中草药饲料添加剂对种鹅繁殖性能和血清生化指标的影响

选择3年龄产蛋种鹅224只(四川白鹅),成年皖西白公鹅56只,随机分为2组,每组4个重复,两组试验基础日粮相同,试验组在对照组日粮的基础上添加3%的中草药添加剂,试验62d。试验结果表明:两组种鹅产蛋率、每枚蛋重、日采食量比对照组分别高8.56%(P>0.05)、0.30%(P>0.05)、1.96%(P<0.05);试验组种鹅料蛋比、蛋破损率比对照组分别低6.31%(P<0.05)和16.01%(P>0.05);入孵种蛋受精率比对照组高6.59%(P<0.05),入孵蛋孵化率比对照组高6.65%(P<0.05),健雏率比对照组高2.09%(P>0.05);试验组种鹅血清中碱性磷酸酶、总蛋白质、总钙、磷、甘油三酯比对照组分别高3.63%、11.48%、8.07%、12.57%和43.83%,差异都不显著(P>0.05);而试验组种鹅血清中尿酸、葡萄糖比对照组分别低17.42%(P>0.05)和2.44%(P>0.05);试验组种鹅血清中三碘甲腺原氨酸、甲状腺素胰岛素、孕酮比对照组分别高5.78%(P>0.05)、15.63%(P>0.05)、6.95%(P>0.05)和15.50%(P<0.05)。     

发酵谷物蛋白对异育银鲫生长及饲料利用率的影响

试验以添加5%的鱼粉作为对照组,不添加鱼粉和发酵谷物蛋白作为空白组,不使用鱼粉但分别添加2%、4%、6%、8%、10%和12%的发酵谷物蛋白作为试验组配制8组配合饲料,饲养异育银鲫90 d。结果显示:发酵谷物蛋白各试验组异育银鲫的增重率及特定生长率均高于对照组和空白组(P>0.05);10%和12%发酵谷物蛋白试验组的饵料系数显著低于对照组和空白组(P<0.05);各发酵谷物蛋白试验组的干物质、粗蛋白质、粗脂肪、粗灰分的表观消化率略高于对照组(P>0.05);4%~12%发酵谷物蛋白试验组总磷表观消化率显著高于对照组(P<0.05),且随着发酵谷物蛋白含量的增加,试验组总磷表观消化率呈递增趋势。发酵谷物蛋白配比以10%~12%(占饲料)为宜。     

外源消化酶对羔羊营养物质消化率及生产性能的影响

研究了外源消化酶对羔羊采食量、生长性能、消化性能以及羔羊营养物质表观消化率的影响.试验分4个组,试验1组饲喂基础饲粮为对照组,其他3组饲喂基础饲粮基础上添加不同外源消化酶组合,研究不同外源消化酶组合对羔羊日采食量、日增重和营养物质表观消化率的影响.结果表明:羔羊日均采食量2组和4组与1组差异显著(P＜0.05),其余之间差异不显著(P＞0.05);3周的平均日增重2组、3组、4均与1组差异显著(P＜0.05),但2组与4组间差异不显著(P＞0.05);干物质、能量、脂肪和无氮浸出物的表观消化率试验组均高于对照组(P＞0.05),但能量的表现消化率2组和4组均显著高于1组和3组(P＜0.05);粗蛋白的表现消化率试验组均显著高于对照组(P＜0.05),试验4组酶制剂组合效果最好.     

酵母核酸对肉仔鸡生长性能和血液生化指标的影响

在肉鸡日粮中添加酵母核酸,研究酵母核酸对肉鸡生长性能和部分血液指标的影响。125只1日龄艾维茵肉鸡,随机分为5组,每组5个重复,每个重复5只。对照组饲喂基础日粮,试验组分别在基础日粮的基础上添加0.1%、0.2%、0.3%、0.4%的酵母核酸。试验期4周,在第2周末和试验结束时,分别测定生长性能,并采取血样,测定血清生化指标。结果表明:添加不同水平的核酸能显著提高后2周的日增重,而在前2周,虽然各试验组均比对照组的日增重有所提高,但只有添加0.3%,0.4%的核酸对肉鸡的日增重的影响较显著(P<0.05);添加酵母核酸后料肉比降低,前2周差异不显著(P>0.05),后2周添加0.3%、0.4%酵母核酸组同对照组比差异显著(P<0.05)。添加酵母核酸能提高两个阶段肌肉中粗蛋白的含量,但前2周,各处理组间差异不显著(P>0.05),后2周,添加0.3%核酸组蛋白质的含量有明显的提高(P<0.05)。前2周,添加酵母核酸对肉鸡血清尿酸、血糖、总胆固醇、甘油三酯、高密度胆固醇以及低密度胆固醇的影响均不显著(P>0.05);后2周,添加酵母核酸对肉鸡血清尿酸、血糖和高密度胆固醇的影响均不显著(P>0.05),而添加0.2%酵母核酸组能显著提高血清胆固醇、甘油三酯和低密度胆固醇的含量(P<0.05)。     

中草药添加剂在乌骨鸡生产中的应用

选择1日龄乌骨鸡243只,随机分成3组,每组设3个重复,每个重复27只。将中草药添加剂I、II按1%的比例添加于日粮中饲喂乌骨鸡,研究中草药添加剂对乌骨鸡生产性能和物质代谢的影响。试验结果表明:与对照组相比,中草药添加剂I、II日增重、料重比差异不显著(P>0.05),成活率分别提高8.7%、5.4%;干物质消化率、有机物消化率和表观氮存留率(ANR),中草药添加剂I与抗生素相近,但中草药添加剂II与抗生素相比,干物质消化率、表现氮存留率分别降低3.57%、9.24%,差异极显著(P<0.01);有机物消化率降低2.68%,差异显著(P<0.05)。     

豌豆在生长猪日粮中应用效果的研究

试验选用 96头体重为 18.9± 2 .5kg的三元杂交 (北京黑×长白×杜洛克 )生长猪 ,随机分为 3个处理 ,处理1为玉米 -豆粕对照组 ;处理 2为用豌豆蛋白取代 2 5 %的基础日粮蛋白组 ;处理 3为用豌豆蛋白取代 5 0 %的基础日粮蛋白组。每个处理 8个重复 ,每个重复 4头猪 ,测定生长猪的生长性能。结果表明 ,试验前期用豌豆蛋白取代基础日粮的部分蛋白 ,可使生长猪的日增重和采食量均显著降低 (P <0 .0 5 ) ,而饲料增重比无明显变化。随着生长猪日龄增加 ,豌豆对其生长性能的影响逐渐减小     

益生素对肉仔鸡生长性能及免疫器官发育的影响

研究益生素对AA肉仔鸡的生长性能及免疫器官发育的影响.对照组饲喂玉米-豆粕型基础日粮,抗生素组在基础日粮中添加50mg/kg金霉素,Ⅰ、Ⅱ组分别添加200、400mg/kg益生素.结果显示:21日龄Ⅰ、Ⅱ组平均日采食量较对照组分别降低1.4％和1.9％,料重比分别降低6.7％和6.7％;Ⅰ组法氏囊重和法氏囊指数分别提高35.4％和36.9％,Ⅱ组胸腺重和胸腺指数分别提高4.5％、9.5％.42日龄Ⅰ、Ⅱ组平均日采食量较对照组分别提高9.9％和3.7％,料重比分别降低1.4％和2.3％;对照组脾脏指数略高于Ⅰ组,显著高于Ⅱ组;Ⅰ、Ⅱ组胸腺重、胸腺指数及法氏囊指数均显著高于对照组.21日龄Ⅰ、Ⅱ组平均日采食量较抗生素组分别提高0.9％和0.4％,料重比分别降低3.1％和3.1％;42日龄Ⅰ、Ⅱ组平均日采食量分别提高5.7％和3.7％,料重比分别降低1.9％和2.8％.以添加水平200 mg/kg的效果较好.     

Nutritional value of wet corn gluten feed for sheep and lactating dairy cows

Experiments were conducted to determine digestibility of wet corn gluten feed in sheep and effect of wet corn gluten feed on DM intake, milk production, and milk composition by dairy cows. In Trial 1, six wethers were fed wet corn gluten feed at maintenance and ad libitum for determination of nutrient digestibility by the conventional 7-d total collection technique. The sheep ate 1.32 times maintenance at ad libitum intake and no significant differences were found in digestibility due to intake. Digestibilities of DM, organic matter, energy, CP, ether extract, ADF, NDF, and hemicellulose averaged 70.3, 73.0, 73.7, 78.3, 72.8, 51.4, 58.1, and 60.4%, respectively. Mean total digestible nutrients for both treatments was 70.3. In Trial 2, 12 Holstein cows in mid to late lactation were allotted to a 4 x 4 Latin square design. Cows were fed a total mixed ration twice daily. Wet corn gluten feed was fed at 0 (control), 10, 20, and 30% of the total ration DM. There were no significant treatment effects on DM intake, milk yield, or milk composition. Dry matter intake (kg/d), milk production (kg/d), and percent milk fat were 21.4, 22.9, and 3.71, respectively, for control; 21.4, 23.0, and 3.80 for the 10%; 21.0, 23.1, and 3.71 for the 20%; and 21.0, 23.2, and 3.89 for the 30% wet corn gluten feed.     

Effects of supplementing a Saccharomyces cerevisiae fermentation product during the periparturient period on performance of dairy cows fed fresh diets differing in starch content

The objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) during the periparturient period (d ?28 ± 3 to 44 ± 3 relative to calving) on dry matter intake (DMI), milk production, apparent total-tract nutrient digestibility, and postpartum ovarian activity of dairy cows fed fresh diets varying in starch content. From d 28 ± 3 before the expected calving date until d 44 ± 3 after calving, 117 Holstein cows were fed diets with SCFP (SCFP; n = 59) or without (control, CON; n = 58). A common, basal, controlled-energy close-up diet (net energy for lactation: 1.43 Mcal/kg; 13.8% starch) was fed before calving. Cows within each treatment (CON or SCFP) were fed either a low- (LS; 22.1% starch) or high-starch (HS; 28.3% starch) diet from d 1 to 23 ± 3 after calving (fresh period), resulting in 4 treatment groups: LS-CON (n = 30), LS-SCFP (n = 29), HS-CON (n = 28), and HS-SCFP (n = 30). All cows were fed the HS diets from d 24 ± 3 to 44 ± 3 after calving (post-fresh period). Cows were assigned to treatment balanced for parity, body condition score, body weight, and expected calving date. Milk yield was higher for cows fed the LS diets compared with those fed the HS diets during the fresh period (34.1 vs. 32.1 kg/d), whereas DMI and 3.5% fat-corrected milk yield (FCM) were not affected by dietary starch content, and LS cows tended to lose more body condition than HS cows (?0.42 vs. ?0.35 per 21 d) during the fresh period. Overall DMI during the close-up and fresh periods did not differ between SCFP and CON cows. However, SCFP supplementation transiently increased DMI on d 1 (13.0 vs. 11.9 kg/d) and 5 (15.5 vs. 14.1 kg/d) after calving compared with CON. During the post-fresh period, SCFP cows tended to eat less than CON cows (19.8 vs. 20.6 kg/d) but had similar 3.5% FCM (44.9 vs. 43.6 kg/d), resulting in greater feed efficiency for SCFP cows (FCM/DMI; 2.27 vs. 2.13). Neither starch content of fresh diets nor SCFP supplementation affected the interval from calving to first ovulation or the incidence of double ovulation. These findings suggest that feeding low-starch diets during the fresh period can increase milk production of dairy cows during the fresh period, and that supplementation of SCFP may increase feed intake around calving and feed efficiency in the post-fresh period.     

The residue levels of narasin in eggs of laying hens fed with unmedicated and medicated feed

Laying hens were fed contaminated feed containing narasin 2.5 mg/kg for 21 days followed by a 7 day withdrawal period, hens in the control group were fed unmedicated feed. Eggs were collected during trial days 0, 3, 7, 14, 21 and after the withdrawal period of 7 days. The concentration of narasin in yolks and egg whites was analyzed by a liquid chromatography-mass spectrometry method. Narasin was found to accumulate in yolks, where the narasin concentration increased during the treatment. The concentration of narasin varied from 5.9 to 13.8 microg/kg (mean 10.6 microg/kg) in yolks after 21 day feeding periods. The concentrations of narasin ranged from < 0.9 to 1.4 microg/kg after the withdrawal period. Narasin residues were not found in egg whites of the laying hens fed contaminated feed nor in either yolks or egg whites of the laying hens fed unmedicated feed. The effect of cooking was also tested on the amount of narasin residues in eggs. Cooking for 10 min did not significantly influence the narasin residues in eggs. Traces of lasalocid were also found in the yolks. The traces of lasalocid are attributable to an accidental contamination of the feed during its manufacture.     

Effect of diet energy level and genomic residual feed intake on bred Holstein dairy heifer growth and feed efficiency

The objective of this study was to determine growth, feed intake, and feed efficiency of postbred dairy heifers with different genomic residual feed intake (RFI) predicted as a lactating cow when offered diets differing in energy density. Postbred Holstein heifers (n = 128, ages 14–20 mo) were blocked by initial weight (high, medium-high, medium-low, and low) with 32 heifers per block. Each weight block was sorted by RFI (high or low) to obtain 2 pens of heifers with high and low genomically predicted RFI within each block (8 heifers per pen). Low RFI heifers were expected to have greater feed efficiency than high RFI heifers. Dietary treatments consisted of a higher energy control diet based on corn silage and alfalfa haylage [HE; 62.7% total digestible nutrients, 11.8% crude protein, and 45.6% neutral detergent fiber; dry matter (DM) basis], and a lower energy diet diluted with straw (LE; 57.0% total digestible nutrients, 11.7% crude protein, and 50.1% neutral detergent fiber; DM basis). Each pen within a block was randomly allocated a diet treatment to obtain a 2 × 2 factorial arrangement (2 RFI levels and 2 dietary energy levels). Diets were offered in a 120-d trial. Dry matter intake by heifers was affected by diet (11.0 vs. 10.0 kg/d for HE and LE, respectively) but not by RFI or the interaction of RFI and diet. Daily gain was affected by the interaction of RFI and diet, with low RFI heifers gaining more than high RFI heifers when fed LE (0.94 vs. 0.85 kg/d for low and high RFI, respectively), but no difference for RFI groups when fed HE (1.16 vs. 1.19 kg/d for low and high RFI, respectively). Respective feed efficiencies were improved for low RFI compared with high RFI heifers when fed LE (10.6 vs. 11.8 kg of feed DM/kg of gain), but no effect of RFI was found when fed HE (9.4 vs. 9.5 kg of DM/kg of gain for high and low RFI, respectively). No effect of RFI or diet on first-lactation performance through 150 DIM was observed. Based on these results, the feed efficiency of heifers having different genomic RFI may be dependent on diet energy level, whereby low RFI heifers utilized the LE diet more efficiently. The higher fiber straw (LE) diet controlled intake and maintained more desirable heifer weight gains. This suggests that selection for improved RFI in lactating cows may improve feed efficiency in growing heifers when fed to meet growth goals of 0.9 to 1.0 kg of gain/d.     

Effect of quantity and route of administration of manganese monoxide on feed intake and serum manganese in ruminants

The experiment investigated effects of high quantities of manganese and route of administration (diet versus capsule-dosed) on feed intake and blood characteristics in sheep. Twenty-four Florida native or Florida native by St. Croix crossbred wethers, 47 kg initially, were assigned randomly to eight treatments including basal diet supplemented with 0, 3000, 6000, or 9000 ppm manganese as a reagent grade manganese monoxide or basal diet plus gelatin capsules containing the equivalent of 0, 3000, 6000, or 9000 ppm manganese based on intake of the previous day. Three sheep per treatment were provided feed and tap water for ad libitum intake. Sheep were fed basal diet for 7 days followed by a 21-day experimental period, then placed back on the basal diet for 7 days. Average daily feed intake was reduced by increasing supplemental manganese, regardless of route. Animals dosed by capsule consumed less feed than those administered manganese in the diet. Serum manganese increased as manganese supplementation increased, but route of administration had no effect.     

Metabolism of arsenic by sheep chronically exposed to arsenosugars as a normal part of their diet. 1. Quantitative intake,uptake, and excretion

Information on the effects of long-term organoarsenical consumption by mammals is limited despite the fact that foodstuffs, especially seafood, often contain organoarsenicals at very high concentrations. Here we evaluate the intake, uptake, and excretion (urine and feces) of arsenic by sheep that live on North Ronaldsay in the Orkney Islands and naturally consume large amounts of arsenosugars through their major food source-seaweed. The sheep eat a broad variety of seaweed species, and arsenic concentrations were determined in all the species observed eaten by the sheep (5.7-74.0 mg kg(-1) dry mass). Because of preference and availability, they feed mostly on the seaweed species found to contain the highest arsenic concentrations: Laminaria digitata and Laminaria hyperborea (74 +/- 4 mg kg(-1) dry mass). To quantify the arsenic intake by the sheep, a feeding experiment reflecting natural conditions as close as possible was set up. In the feeding trial, the average daily intake of arsenic by 12 ewes was 35 +/- 6 mg (97% of water-extractable arsenic was present as arsenosugars) gained from feeding on the two brown algae. To test the possible influence of microflora on the metabolism of arsenosugars, six of the sheep were adapted to feeding on grass for 5 months before the start of the trial (control sheep), and the remaining six sheep were kept on their normal seaweed diet (wild sheep). No significant difference in seaweed/arsenic intake and arsenic excretion was found between the two groups of sheep. The arsenic excreted in the feces represents 13 +/- 10% (n = 12) of the total consumed, and on the assumption of that, the average urinary excretion is estimated to 86%.The main arsenic metabolite excreted in urine was dimethylarsinic acid (DMA(V)) (60 +/- 22%) and minor amounts of dimethylarsinoylethanol (DMAE), methylarsonic acid (MA(V)),tetramethylarsonium ion (TMA+), and arsenate (As(V)) together with seven unknown arsenic compounds were also excreted. The urinary arsenic excretion pattern showed a lag period (>4 h) before significant quantities appeared in the urine, an excretion rate that peaked between 4 and 28 h after seaweed intake and a relatively slow half-life (17 h) after end of intake.     

Performance of lactating dairy cows fed whole cottonseed coated with gelatinized cornstarch.

The handling characteristics of whole cottonseed are improved by coating with gelatinized cornstarch, but limited information is available on the effects of feeding the coated cottonseed to lactating dairy cows. Thirty-six lactating Jersey cows were used in a crossover design trial with 4-wk experimental periods to evaluate the influence of coating whole cottonseed with 2.5% gelatinized cornstarch on dry matter intake, milk yield, and composition. Cows were fed diets containing 10.2% alfalfa-orchardgrass hay, 45.2% corn silage, 15.0% coated or uncoated whole cottonseed, and 29.6% concentrate for ad libitum consumption. Coating whole cottonseed with gelatinized cornstarch tended to reduce dry matter intake, which averaged 16.2 and 15.9 kg/d for uncoated and coated cottonseed, respectively. Milk yield and composition were similar for uncoated and coated cottonseed. The yield of energy-corrected milk per unit of dry matter consumed was greater with coated cottonseed. Cows fed coated cottonseed gained body weight, but cows fed uncoated cottonseed lost weight. Concentrations of plasma urea were similar among treatments; however, NEFA concentrations were lower for cows fed coated whole cottonseed. Results of this trial indicate that coating whole cottonseed with 2.5% gelatinized cornstarch does not alter its feeding value for lactating dairy cows.     

Different milk feeding intensities during the first 4 weeks of rearing in dairy calves: Part 1: Effects on performance and production from birth over the first lactation

We aimed to test the effects of ad libitum feeding of whole milk (WM) or milk replacer (MR) versus restrictive feeding of MR during the first 4 wk of life on growth performance and on milk yield in the first lactation. We studied 57 German Holstein calves (29 females, 28 males) from birth until d 110 of life (trial 1). The 28 females from trial 1 were further studied during their first lactation (trial 2). In trial 1, all calves were randomly allocated at birth to 1 of 3 groups: MR-res [n = 20, 6.78 kg MR (11.5% solids)/calf per day], MR-ad lib (n = 17, 13.8% solids) or WM-ad lib (n = 20). All calves received colostrum ad libitum from their dam until d 3 of age. From d 4 to 27, calves were fed according to their group regimen. From d 28 to 55, all calves received MR-res feeding and were then gradually weaned until d 69. We recorded body weight (until d 110) and feed intake (amount, metabolizable energy, and frequency of liquid feed intake until weaning). We estimated the profitability of the different feeding regimens, taking into account income from milk yield (trial 2) and feed costs during rearing. In trial 1, the calves from WM-ad lib and MR-ad lib had total metabolizable energy intakes 2.02- and 1.65-fold greater than the MR-res group during the first 4 wk of life. During this period, concentrate intake did not differ among groups, but tended to be greater in WM-ad lib than in MR-ad lib calves from d 28 to 69. The MR-res calves visited the automatic feeders more often than the ad libitum-fed groups during differential feeding, but 70% of the visits were unrewarded (<10% in the ad libitum-fed calves). When all calves were fed at the MR-res level, the average proportion of unrewarded visits was 65% in all groups. Average daily gain and body weight were greater among MR-ad lib and WM-ad lib calves than among MR-res animals during the first 4 wk of life, but not from d 1 to 110. In trial 2, age at first calving, dry matter intake, and body weight over the first 10 mo of lactation were not different among groups, nor was milk composition. Milk yields (305 d) were numerically but not statistically greater in the ad libitum-fed groups during the first lactation (+765 kg for WM-ad lib vs. MR-res; +612 kg for MR-ad lib vs. MR-res). Feeding WM-ad lib and MR-ad lib was 1.37- and 1.21-fold more costly than MR-res, respectively, but amounted to 18, 15, and 13% of the total estimated feed costs until first calving in WM-ad lib, MR-ad lib, and MR-res, respectively. Our study confirms that ad libitum feeding is an attractive measure for rearing dairy calves, both for animal welfare and—with the caveat of a small sample size in trial 2 that led to insufficient power—economic profit from milk.