日粮磷进食水平对西杂后备母牛日粮磷表观消化率的影响

为了研究日粮磷进食量对肉牛日粮磷表观消化的影响,试验选用体况良好、体重一致(347 kg±25 kg)的杂交后备母牛(西门塔尔牛(♂)×中国黄牛(♀))16头,随机分为4组,即处理1、2、3和4组,每组4头,各试验组日粮磷的进食量分别为26、34、42和50 g/d,以精料饲喂量调整磷进食水平(每天育成母牛精料喂量分别为1.5、2.5、3.5和4.5 kg),粗料(玉米秸秆青贮)自由采食。总试验期30 d,预饲期20 d后进入正试期,试验最后7 d全收集粪样。结果表明,不同日粮磷进食量对消化道磷的表观消化量和表观消化率有显著影响(P<0.05),在日粮磷进食量为34g/d(日粮磷水平0.51%)时,消化率达最大(53.8%);日粮磷进食量大于34 g/d时,磷进食的增加使磷的表观消化率明显降低(P<0.05)。     

日粮营养水平对西杂育成母牛日粮消化能和粪能排出量的影响

为了研究日粮营养水平(精料进食水平)对肉牛日粮消化能和粪能排出量的影响,试验选用体况良好、体重一致(347 kg±25 kg)的杂交后备母牛(西门塔尔牛(♂)×中国黄牛(♀))16头,随机分为4组,即处理Ⅰ组、Ⅱ组、Ⅲ组和Ⅳ组,每组4头,各试验组日粮精料进食量分别为1.5、2.5、3.5和4.5 kg,粗料(青贮)自由采食。总试验期为30 d,预饲期20 d后进入正试期,试验期最后7 d全收集粪样。结果表明:不同日粮处理间全消化道蛋白质、淀粉的表观消化量和日粮消化能有显著差异(P<0.05),并随日粮营养水平(精料进食水平)的增加而增加,但不同日粮处理间中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的表观可消化量没有差异,粪中能量的排出量也没有明显差异(P>0.05)。日粮可消化有机物与消化能的进食量呈直线强相关,即消化能DE(MJ/d)=0.669+18.476 DOM(kg/d)(R2=0.999 6,n=4)。     

日粮精料中麸皮比例对西门塔尔杂交后备母牛日粮营养物质消化率的影响

文章旨在采用消化试验研究肉牛日粮精料中麸皮比例对日粮营养物质表观消化率的影响。试验选取体况良好、体重一致(369.5 kg±37.8 kg)的杂交后备母牛(西门塔尔牛(♂)×中国黄牛(♀))24头,随机分为6组,即试验Ⅰ组、Ⅱ组、Ⅲ组、Ⅳ组、Ⅴ组和Ⅵ组,每组4头,分别定量饲喂6种不同麸皮水平的精料日粮(3.5kg/d),粗料(青贮)自由采食;各试验组精料麸皮水平分别为0%、10%、20%、30%、40%和50%;预饲期20 d,试验期30 d,试验最后7 d收集全部粪样。结果表明:日粮精料中麸皮水平对日粮有机物(OM)、粗蛋白质、淀粉和中性洗涤纤维(NDF)的消化道表观消化率没有显著影响(P>0.05),不同麸皮水平日粮的OM、CP、淀粉和NDF的消化道表观消化率变化范围分别为49.40%～55.52%、48.56%～53.90%、88.87%～93.29%、48.11%～57.91%。     

肉牛日粮精料进食水平对淀粉的瘤胃发酵和小肠表观消化率的影响

为了研究日粮精料进食水平对肉牛真胃食糜淀粉流量及其表观消化率的影响,试验选择体重650kg左右荷斯坦(Holstein)公牛3头,安装有瘤胃、真胃瘘管,按3×3拉丁方试验设计分别饲喂粗料进食量相同而精料进食量不同的3种日粮,以三氧化二铬(Cr2O3)作真胃食糜标记物,全收粪法收集粪样,测定真胃食糜和粪中的淀粉流量及在瘤胃内、真胃后段消化道(简称肠道)内的表观消化率。结果表明:日粮精料进食水平对瘤胃及全消化道的淀粉表观消化率没有显著影响(P>0.05),日粮精料水平明显影响到达真胃的淀粉量(P<0.05)。     

育成母牛日粮麸皮水平对营养物质消化率影响

通过饲养试验,主要研究日粮含不同麸皮水平对奶用育成母牛日粮营养物质消化率的影响。选取16头15月龄体况基本一致的荷斯坦育成母牛为试验动物进行消化代谢试验。试验动物随机分为4组,每组4头牛,分别定量(3.5 kg/d)饲喂6种不同麸皮水平的精料日粮,粗料为固定给量的自由采食(8 kg/d)。4个处理组的日粮麸皮水平为0、12.8%、24.8%和44.7%。预试期为20 d,正试期为10 d,采用全收粪法收集6 d粪便。试验结果表明:在采食量和精粗比相似的情况下,日粮精料高比例(45%)麸皮明显降低奶用育成母牛日粮有机物、中性洗涤纤维和酸性洗涤纤维表观消化率,而对蛋白质表观消化率无显著影响。     

不同磷源对育成母牛日粮磷表观消化率的影响

本文旨在采用消化试验研究育成母牛日粮中不同磷源(植物磷源或补充部分矿物磷源)对日粮总磷表观消化率的影响.试验选用体况良好、体重一致的15月龄荷斯坦育成母牛12头,随机分为3组,即试验1组、2组和3组,每组4头,分别定量(3.50kg/d)饲喂3种不同精料日粮,粗料(青贮)自由采食,以磷酸氢钙替代部分植物磷源,日粮总磷为0.57％～0.60％;试验期为30d,预试期20d后进入正试期,试验最后7d全收集粪样和尿样;结果表明不同磷源处理间日粮的总磷消化道表观消化量和表观消化率没有显著差异(P＞0.05),总磷的表观消化率为38.2％.     

日粮磷水平对空怀期云南半细毛羊养分消化率的影响

为研究日粮磷(P)水平对空怀云南半细毛羊养分消化率的影响,选择25只空怀期云南半细毛羊随机分为5组,分别饲喂5种不同磷水平(0.19%、0.32%、0.45%、0.56%和0.64%)日粮,14 d预饲期后进行消化试验(5 d)。采样期每天采集各组精料200 g,粗料200 g。每只羊的鲜粪样混匀称重后取20%分成两份,一份按5%的比例加入10%的稀盐酸进行固氮。每天采集的饲料样和粪样经55℃风干后回潮24 h,粉碎过40目筛,进行相应指标的测定。结果表明:日粮磷水平对钙(Ca)的表观消化率无影响(P0.05)。随着日粮磷水平的增加,干物质(DM)和粗蛋白质(CP)表观消化率逐渐降低,且0.19%、0.32%磷水平组极显著高于0.64%磷水平组(P0.01);能量(EG)、粗脂肪(EE)、粗灰分(Ash)、中性洗涤纤(NDF)和酸性洗涤纤维(ADF)表观消化率逐渐升高后降低再逐渐升高,拐点出现在0.45%磷水平组。随着日粮磷水平的增加,磷的表观消化率逐渐降低,0.19%磷水平组极显著高于0.45%、0.56%、0.64%磷水平组(P0.01),其他组间差异不显著(P0.05)。通过回归分析发现,日粮磷水平与干物质、粗蛋白质、磷的表观消化率之间呈显著的线性关系(R~2分别为0.7823、0.8386、0.9976)。综上所述,在本试验条件下,日粮磷水平对空怀期云南半细毛羊钙的表观消化率无影响,随日粮磷水平的增加,干物质、粗蛋白质和磷的表观消化率逐渐降低。当日粮磷水平为0.32%时空怀期云南半细毛羊对主要营养成分的表观消化率最高。     

日粮精料进食水平对肉牛消化道营养物质流量和表观消化率的影响

为了研究日粮精料进食水平对肉牛真胃食糜营养流量和营养物质表观消化率的影响,试验选择体重650kg左右荷斯坦(Holstein)公牛3头,安装有瘤胃、真胃瘘管,按3×3拉丁方实验设计分别饲喂粗料进食量相同而精料不同的3种日粮,以三氧化二铬(Cr2O3)作真胃食糜标记物,全收粪法收集粪样,测定真胃食糜和粪中的有机物(OM)、粗蛋白质(CP)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)流量及在瘤胃内、真胃后段消化道(简称肠道)内的表现消化率.结果表明日粮精料进食水平对瘤胃及全消化道的OM、NDF、ADF表观消化率没有显著影响(P＞0.05),日粮精料水平明显影响到达真胃的OM和蛋白质量(P＜0.05),但全消化道CP表观消化率没有差异(P＞0.05).     

日粮磷水平对空怀期云南半细毛羊养分消化率的影响

为研究日粮磷（P）水平对空怀云南半细毛羊养分消化率的影响，选择25只空怀期云南半细毛羊随机分为5组，分别饲喂5种不同磷水平（0.19%、0.32%、0.45%、0.56%和0.64%）日粮，14 d预饲期后进行消化试验（5 d）。采样期每天采集各组精料200 g，粗料200 g。每只羊的鲜粪样混匀称重后取20%分成两份，一份按5%的比例加入10%的稀盐酸进行固氮。每天采集的饲料样和粪样经55℃风干后回潮24 h，粉碎过40目筛，进行相应指标的测定。结果表明：日粮磷水平对钙（Ca）的表观消化率无影响（P>0.05）。随着日粮磷水平的增加，干物质（DM）和粗蛋白质（CP）表观消化率逐渐降低，且0.19%、0.32%磷水平组极显著高于0.64%磷水平组（P<0.01）；能量（EG）、粗脂肪（EE）、粗灰分（Ash）、中性洗涤纤（NDF）和酸性洗涤纤维（ADF）表观消化率逐渐升高后降低再逐渐升高，拐点出现在0.45%磷水平组。随着日粮磷水平的增加，磷的表观消化率逐渐降低，0.19%磷水平组极显著高于0.45%、0.56%、0.64%磷水平组（P<0.01），其他组间差异不显著（P>0.05）。通过回归分析发现，日粮磷水平与干物质、粗蛋白质、磷的表观消化率之间呈显著的线性关系（R²分别为0.7823、0.8386、0.9976）。综上所述，在本试验条件下，日粮磷水平对空怀期云南半细毛羊钙的表观消化率无影响，随日粮磷水平的增加，干物质、粗蛋白质和磷的表观消化率逐渐降低。当日粮磷水平为0.32%时空怀期云南半细毛羊对主要营养成分的表观消化率最高。     

不同日粮对肉牛瘤胃可发酵有机物和全消化道有机物表观消化的影响

为了研究不同日粮有机物瘤胃发酵量与全消化道消化量之间的关系,选择体重600 kg左右的荷斯坦(Holstein)公牛3头,安装瘤胃、真胃瘘管,以三氧化二铬(Cr2O3)作真胃食糜标记物,全收粪法收集粪样,测定真胃食糜和粪中的有机物(OM)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)流量及在瘤胃内、全消化道的表观消化,分别以3×3拉丁方和2×3不完全拉丁方试验设计测定不同日粮有机物瘤胃发酵率和消化道表现消化率,试验Ⅰ为饲喂粗料进食量相同而精料进食量不同的3种日粮,试验Ⅱ为以豆粕、全脂大豆为蛋白质补充料来源的2种等蛋白日粮.结果表明:不同日粮对瘤胃及全消化道的OM、NDF、ADF表观消化率没有显著影响(P＞0.05),但明显影响有机物瘤胃可发酵量(P＜0.05);日粮有机物瘤胃表观发酵量(FOM,g/d)与日粮有机物全消化道消化量(DOM,g/d)有显著的相关关系:DOM(g/d)=1.27×FOM(g/d)+962.81(r2=0.95,n=5,P＜0.01).     

Performance, carcass, cartilage calcium, sensory and collagen traits of longissimus muscles of open versus 30-month-old heifers that produced one calf

One hundred eleven Simmental x Hereford (3/8 to 5/8 Simmental) heifers were used to determine the effects of age, parturition and implantation on performance, carcass and meat-sensory traits, muscle-collagen characteristics and thoracic-button calcification. Eighty-five heifers that calved at about 2 yr of age, designated as single-calf heifers (SCH), were either implanted (I-SCH) with Synovex-H or not implanted (NI-SCH). The remaining 26, 2-yr-old non-pregnant heifers (2-OH) served as controls. Additionally, 24, 1-yr-old open heifers (1-OH) from the same genetic source were utilized as the standard heifer-production system. The 1-OH and 2-OH were slaughtered after being fed a high-grain diet for 137 and 112 d, respectively. The SCH were fed the same high-grain diet beginning about 1 mo after calving and were fed 137 d before slaughter. The 33 I-SCH were implanted when started on the high-grain diet. Calves were weaned about 5 wk before the SCH were slaughtered. The 2-OH had the highest (P less than .05) feedlot ADG, whereas no differences (P greater than .05) occurred among other treatments. Dressing percentages were higher (P less than .01) for I-SCH than for NI-SCH. Carcass weights were lowest (P less than .05) and percentage kidney, pelvic and heart fat was highest (P less than .01) for 1-OH. Fat thickness, yield grades, marbling scores and quality grades were similar (P greater than .05) and desirable for all treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Poultry Manure as a Supplement in High Concentrate Diets Limit-Fed to Beef Cows

Three trials were conducted to evaluate poultry manure as a CP and mineral supplement in high concentrate diets limit-fed to gestating and lactating beef cows and heifers. Trial 1 used 67 pregnant Simmental x Angus beef cows (BW, 640 ± 6 kg). During this 126-d trial, no differences (P>0.10) in BW changes or body condition scores (BCS) were observed between cows provided supplemental CP and minerals from either poultry manure or a soybean meal-based protein and mineral supplement. Feed costs per day were lower for cows fed diets supplemented with poultry manure ($0.82) than for those fed diets supplemented with the soybean meal-based protein and mineral supplement ($1.11) and were much lower than those for cows fed an all hay diet offered for ad libitum intake ($1.46). In Trial 2, 26 pregnant Simmental x Angus beef heifers (BW, 503 ± 11 kg) were used to determine the efficacy of poultry manure as a source of energy, protein, and minerals. No differences (P>0.10) in performance were observed between heifers consuming a low poultry manure diet (4.6 kg/d corn and 1.1 kg/d poultry manure) or a high poultry manure diet (3.1 kg/d corn and 3.2 kg/d poultry manure). Feed costs per day were lower for heifers on the high poultry manure treatment ($0.61 vs $0.73 for high and low poultry manure treatments, respectively). Trial 3 was conducted with 61 beef cows and 23 beef heifers in late gestation. Animals consuming the poultry manure-supplemented, corn-based diet lost more weight during both the gestation (P<0.10) and lactation periods (P<0.05) than those fed the soybean meal-based protein and mineral supplement. Overall BCS change was similar among treatments (P=0.31). Feed costs per day were lower for cows fed supplemental poultry manure ($0.82) than for those fed the soybean meal-based protein and mineral supplement ($1.11). Poultry manure was a more economical source of supplemental CP and minerals than a soybean meal-based protein and mineral supplement when fed to meet nutrient needs of cows that were limit-fed a corn-based diet. Effects on cow performance were minimal.     

Growth, reproductive performance, and manganese status of heifers fed varying concentrations of manganese

An experiment was conducted to examine the effects of dietary Mn on growth, reproductive performance, and Mn status of beef heifers. Eighty Angus (n = 40) and Simmental (n = 40) heifers, averaging 249 kg, were stratified by BW within a breed and randomly assigned to 1 of 4 treatments providing 0 (control), 10, 30, or 50 mg of supplemental Mn/kg of DM from MnSO(4). Heifers were individually fed a diet containing cottonseed hulls, corn gluten feed, citrus pulp, and ground corn, and the control diet contained 15.8 mg of Mn/kg of DM by analysis. Average daily gain, DMI, and G:F for the 196-d period were not affected by Mn supplementation. Control heifers had reduced (P = 0.04) liver Mn when contrasted with the 3 levels of supplemental Mn. Serum cholesterol was greater (P = 0.001) in Angus compared with Simmental heifers over the course of the 196-d experiment but was not affected by treatment. Dietary Mn did not significantly affect measures of reproductive performance. Results of this study indicate that 15.8 mg of Mn/kg of diet DM should be adequate for growth, onset of estrus, and conception of beef heifers.     

Effect of timing of feeding a high-concentrate diet on growth and attainment of puberty in early-weaned heifers

Precocious puberty (<300 d of age) can be successfully induced in a majority of heifers with early weaning and continuous feeding of a high-concentrate diet. The objective of this experiment was to determine the relative effects of timing of feeding a high-concentrate diet on age at puberty in early-weaned heifers. Sixty crossbred Angus and Simmental heifer calves were weaned at 112 +/- 2 d of age and 155 +/- 3 kg of BW and were fed a receiving diet for 2 wk. Heifers were blocked by age and BW, and assigned randomly to receive a high-concentrate (60% corn; H) or control (30% corn; C) diet during phase 1 (mean age 126 to 196 d) and H or C during phase 2 (mean age 196 to 402 d), resulting in 4 treatments (HH, n = 15; HC, n = 15; CH, n = 15; and CC, n = 15). Blood samples were collected weekly beginning at a mean age of 175 d and assayed for progesterone concentration to determine age at puberty. After 56 d on the experimental diets, BW of heifers fed the H diet during phase 1 were greater (P < 0.05) than those of heifers fed the C diet (mean age of 182 d; treatment x mean age, P < 0.01). After 70 d on the new diets (mean age of 266 d), heifers fed the H diet during phase 2 reached heavier BW (P < 0.05) than heifers fed the C diet, when compared within phase 1 diet groups (HH > HC; CH > CC). Body weights in HC and CH treatments differed from a mean age of 169 through 238 d, after which BW did not differ between these treatments. The ADG over the entire experimental period was greatest for the HH treatment (1.2 +/- 0.04 kg/d; P < 0.05), followed by the HC and CH treatments (1.0 +/- 0.03 and 1.0 +/- 0.02 kg/d, respectively), which were not different, and the CC treatment gained the least (0.7 +/- 0.04 kg/d; P < 0.05). Precocious puberty occurred in 67, 47, 47, and 20% of heifers in the HH, HC, CH, and CC treatments, respectively (HH > CC; P < 0.05). Mean age at puberty for the HH and HC treatments (271 +/- 17 and 283 +/- 17 d of age, respectively) was earlier (P < 0.05) than for the CC treatment (331 +/- 11 d of age). Age at puberty in the CH treatment (304 +/- 13 d of age) was intermediate to and not different from the other treatments. Heifers fed the H diet during phase 1 attained puberty earlier (P < 0.05) than heifers fed the C diet during phase 1. In conclusion, increasing dietary energy intake in early-weaned heifers, through feeding a high-concentrate diet from 126 to 196 d of age, decreased age at puberty regardless of the diet fed after 196 d of age.     

Effects of Prenatal Androgenization and Implantation on the Performance and Carcass Composition of Lactating Heifers in the Single-Calf Heifer System

Two experiments were conducted to evaluate feedlot performance of heifers and calves and the lactational characteristics and carcass composition and quality of heifers while in the single-calf heifer (SCH) system. In Exp. 1, 24 lactating Angus × Holstein heifers were slowly adapted to an 85% concentrate diet, and one-half of the heifers were implanted with Finaplix-H®, both at 11 wk postpartum. Heifer-calf pairs were then placed in feedlot pens, equipped with pinpointer feeding devices, and fed an 85% concentrate diet for 102 d. The control (C) and implanted (I) heifers had similar (P=0.27) daily gains and similar (P=0.30) DMI; however, I heifers consumed 8.9% less (P<0.05) DM as a percentage of BW. Pair efficiency of feed conversion tended to be higher (P<0.09) for I heifers than for C heifers. Hot carcass weight tended to be higher (P<0.10) for the I heifers. Ribeye area was 13% greater (P<0.05) and marbling score was 8.7% lower (P<0.01) for the I heifers than for the C heifers. In Exp. 2, 26 lactating Angus × Simmental heifers were used in the SCH system. Heifer adaptation to a high concentrate diet began 3 to 4 wk prepartum. Two to 3 d postpartum, 16 control (C) and 10 prenatally androgenized (PA) heifer-calf pairs were weighed, and eight C and five PA heifers were implanted with Synovex-H®. They were then placed in feedlot pens equipped with pinpointer feeding devices. By 1 wk postpartum, all heifers were adapted to an 85% concentrate diet and fed until they possessed approximately 1.1 cm s.c. fat cover over the 12th and 13th ribs. Heifers were slaughtered 12 h postweaning. The PA heifers tended to consume more (P<0.11) DM than C heifers. Gain:feed (G:F) was similar (P=0.35) for the C and PA heifers; however, the C heifers tended to have an improved (P<0.08) pair G:F. Heifer G:F and pair G:F were both similar (P=0.53) for the I and nonimplanted heifers. Most carcass measurements were unaffected by treatment; however, the I heifers tended to have higher marbling scores (P<0.07).     

肉用、乳肉兼用西门塔尔牛与河北本地西杂牛杂交效果分析

［目的］本研究旨在探究肉乳兼用型和乳肉兼用型西门塔尔牛与河北省本地西杂牛杂交的改良效果,为河北省培育优质肉牛提供参考。［方法］本研究采用肉乳兼用型西门塔尔牛（MD）冻精与乳肉兼用型西门塔尔牛（DM）冻精与河北省本地西杂母牛进行杂交,测定其后代的生长发育指标,对两种杂交后代的生长发育性状进行比较分析。［结果］MD杂交后代的初生、3月龄、6月龄及12月龄体重均大于DM杂交后代,但结果差异不显著;日增重随着月龄增加而逐渐下降,其中除4~6月龄时DM杂交后代母牛日增重大于MD杂交后代母牛外,其余时期MD杂交后代的日增重均大于DM杂交后代;MD杂交后代胸围和腹围大于DM杂交后代,体高、十字部高及体斜长小于DM杂交后代。［结论］本研究中肉乳兼用型杂交后代较乳肉兼用型杂交后代具有更好的生长发育性能,但差异不显著。     

应用体尺指标估测西杂后备母牛体重

通过测定张掖市甘州区甘浚镇120头西门塔尔杂交后备母牛的体高、胸围、体斜长和实际体重，发现后备母牛生长符合母牛育成期的生长规律，可以用公式来估测后备母牛的体重，用约翰逊公式和体重估测系数估测体重误差率均在5％以下。     

鸡对植酸磷利用率的研究

给3周龄肉鸡、6周龄肉鸡和30周龄蛋鸡分别喂以植酸磷水平为0.18％和0．24％的玉米-豆粕饲粮,研究肉鸡和蛋鸡对饲粮植酸磷的表现消化率。结果表明,蛋鸡植酸磷表现消化率比肉鸡高,而6周龄的肉鸡比3周龄的肉鸡高。     

饲用复合酶对蛋用种鸡日粮磷的利用和生产性能的影响

本试验旨在研究低磷日粮添加复合酶制剂对蛋用种鸡磷的利用和生产性能的影响。选用972只24周龄罗曼褐父母代种鸡,分为3个处理,每处理6个重复,每重复54只种鸡。采用玉米-豆粕-杂粕型基础饲粮,正对照组含总磷0.55%,非植酸磷0.40%,不加酶;负对照组含总磷0.40%,非植酸磷0.21%,不加酶;试验组含总磷0.40%,非植酸磷0.21%,加酶制剂。试验期18周。结果表明:在低非植酸磷的日粮中添加复合酶,粪便中磷含量极显著低于正对照组(P<0.01);粪便中粗蛋白质含量显著低于正对照组和负对照组(P<0.05);显著改善蛋黃顔色(P<0.05);不影响生产性能、骨骼发育和蛋壳质量。添加200 g/t复合酶替代罗曼褐蛋用种鸡日粮中75%的磷酸氢钙能够降低饲料成本,提高养殖企业的经济效益,对罗曼褐蛋用种鸡生产性能无不利影响。