Effects of freeze-dried Mitsuokella jalaludinii culture and Natuphos(®) phytase supplementation on the performance and nutrient utilisation of broiler chickens

BACKGROUND: Phytate‐bound phosphorus (P) in poultry diets is poorly available to chickens. Hence exogenous phytase is often added to their diets. Mitsuokella jalaludinii is a rumen bacterial species that produces high phytase activity. In this study the effects of freeze‐dried active M. jalaludinii culture (FD‐AMJC) and Natuphos^® phytase (phytase N) supplementations on the growth performance and nutrient utilisation of broiler chickens fed a low‐available P (aP) diet were evaluated. RESULTS: Supplementation of FD‐AMJC or phytase N to the low‐aP diet improved the feed intake, feed conversion rate, body weight gain, dry matter (DM) digestibility and P, Ca and Mn retention, increased the tibia bone ash content, Ca and P concentrations in tibia DM and P and Zn concentrations in plasma and reduced the P excretion of broiler chickens. However, the feed conversion rate, P and Ca retention, DM digestibility and reduction of P excretion were better with FD‐AMJC than phytase N supplementation. Supplementation of FD‐AMJC to the low‐aP diet also improved the apparent metabolisable energy value of the diet, Cu and Zn retention and crude protein digestibility, but phytase N supplementation did not. CONCLUSION: FD‐AMJC supplementation was more efficient in improving nutrient utilisation and reducing P excretion in chickens than phytase N supplementation. Copyright © 2011 Society of Chemical Industry     

不同植酸酶理化性能及肉鸡应用效果研究

本研究选用七种不同植酸酶产品,通过粒度分布、水分、灰分、容重、耐热性、体外对植酸磷的释放效应等方面进行不同植酸酶物理特性的评估,同时在零无机磷的极端饲料配方下,观察不同植酸酶对肉鸡生长性能和胫骨发育的影响,以综合评估不同植酸酶的功效。结果表明:不同植酸酶的几何平均粒径无差异(P0.05),但算术平均粒径和粒度模数差异显著(P0.001),植酸酶A、B、F和G颗粒可能更细更集中;水分、灰分含量和容重差异显著(P0.05),植酸酶A和F更有益于在配合饲料中的混合和均匀分布;不同植酸酶耐热性能不同(P0.001),A和G表现更好;体外酶解释放磷的效果差异极显著(P0.01),植酸酶A的体外磷释放率较高;相比于其他植酸酶,肉鸡饲粮中添加植酸酶A,能够极显著提高肉鸡采食量(P0.01),且有提高期末体重和平均日增重的趋势(P=0.083)。此外,处理A表现出了更大的肉鸡胫骨重(P0.05)。不同植酸酶产品理化特性比较及在肉鸡上的实际饲喂效果存在差异,可见,对植酸酶的评估不能从单一方面(如耐热性)考虑,应综合植酸酶的粒度分布和均匀度、耐热性能、肉鸡生长性能和养分释放效应以及胫骨发育等指标科学系统评估。     

Effect of grain source and exogenous phytase on phosphorus digestibility in dairy cows

Two experiments were conducted to determine P digestibility in lactating dairy cows fed corn or barley as grain sources. The first experiment utilized a replicated incomplete 5 × 4 Latin square design with 8 lactating Holstein cows fed diets containing either corn alone or corn in combination with one of 4 barley varieties that differed in chemical composition. Total tract digestibility of P ranged from 11 to 29% for diets containing the barley varieties and was approximately 35% for the corn diet. A second experiment compared P digestibility in cows fed diets containing corn or barley when exogenous phytase was added to the diets. Lactating Holstein cows (n = 16) were arranged in 4 replications of a Latin square with 2 grains (barley or corn), fed separately or with added exogenous phytase (427 phytase units/kg of total mixed ration and 4 periods of 21 d. Phytate P comprised about 50% of the total P (0.46% P) in the total mixed ration. The concentration of serum inorganic P was higher in cows fed diets with exogenous phytase (5.8 vs. 6.5 mg/dL in cows fed barley diets and 5.5 vs 6.0 mg/dL in cows fed corn diets). Using acid detergent lignin as an internal marker, hydrolysis of phytate P was increased by the exogenous phytase, and total P digestibility tended to be increased. In contrast to Experiment 1, in Experiment 2 there was no effect of grain source on P digestibility and total fecal P. Dry matter intake and efficiency of milk production were not affected by exogenous phytase or grain type. Although phytase activity occurs in the rumen, physical properties of the diet and ruminal passage rates may prevent total hydrolysis of phytate in the rumen of lactating cows. Thus, exogenous dietary phytase might improve P digestibility in dairy cows in some dietary situations.     

Starch source evaluation in calf starter: I. Feed consumption, body weight gain, structural growth, and blood metabolites in Holstein calves

Holstein calves were fed pelleted iso-starch (25% of starter dry matter) diets containing barley (n = 16), corn (n = 16), oat (n = 16), and wheat (n = 16) starch for 12 wk of age. Feed consumption, nutrient intake, body weight (BW) gain, skeletal growth, and selected blood metabolites in calves during preweaning (d 1 to 49) and postweaning (d 50 to 84) periods were measured. Average daily starter consumption during pre-weaning and postweaning periods was the greatest in calves fed corn died followed by those fed a wheat diet and then in those fed barley and oat diets. During the preweaning period, the calves provided corn and wheat diets consumed greater amount of mixed grass hay than those fed barley and oat diets. During the postweaning period, mixed grass hay intake was the greatest in calves provided corn diet followed by those fed a wheat diet and then in those fed barley and oat diets. Nutrients (dry matter, crude protein, starch, and neutral detergent fiber) intake followed the solid feed consumption pattern in calves. Body weight and body measurements (body length, body barrel, heart girth, wither height, and hip height) at birth and at weaning (d 49) in calves fed different starch sources were similar. Body weight and body measurements at postweaning (d 84) were the greatest in calves fed a corn diet followed by those fed a wheat diet and then in those fed barley and oat diets. Overall average BW gain and total dry matter intake were the greatest in calves fed a corn diet than in those fed wheat, barley, and oat diets. Feed efficiency was greater in calves fed corn and wheat diets than in those fed barley and oat diets. Blood glucose, blood urea N, triglycerides, cholesterol, and creatinine were reduced with the advancing age of calves. Lesser blood glucose and greater blood urea N concentrations at wk 8, 10, and 12 of age were noticed in calves fed corn diet than in those fed barley, oat, and wheat diets. Occurrence of diarrhea was more frequent in calves fed oat diet than in those provided barley, corn, and wheat diets. Starch sources did not influence respiratory score, rectal temperature, and general appearance score. In conclusion, the calves on corn diet consumed more solid feed and gained greater BW than those fed barley, oat, and wheat diets.     

The effects of forage particle length and exogenous phytase inclusion on phosphorus digestion and absorption in lactating cows

Accurate estimates of phosphorus (P) availability from feed are needed to allow P requirements to be met with reduced P intake, thus reducing P excretion by livestock. Exogenous phytase supplementation in poultry and swine diets improves bioavailability of P, and limited research suggests that this strategy may have some application in dairy cattle rations. The effects of exogenous phytase and forage particle length on site and extent of P digestion were evaluated with 5 ruminally and ileally cannulated lactating cows (188 ± 35 d in milk). Cows were assigned in a 2 × 2 factorial arrangement of treatments in 2 incomplete Latin squares with four 21-d periods. Diets contained P slightly in excess of National Research Council requirements with all P from feed sources. During the last 4 d of each period, total mixed ration, refusals, omasal, ileal, and fecal samples were collected and analyzed for total P, inorganic P (Pi), and phytate (Pp). Total P intake was not influenced by dietary treatments but Pp intake decreased and Pi intake increased with supplemental phytase, suggesting rapid action of the enzyme in the total mixed ration after mixing. Omasal flow of Pi decreased with phytase supplementation, but we observed no effect of diet in ileal flow or small intestinal digestibility of any P fraction. Fecal excretion of total P was slightly higher and Pp excretion was lower for cows receiving diets supplemented with phytase. Milk yield and composition were unaffected by diets. When phytase was added to the mixed ration, dietary Pp was rapidly degraded before intake and total-tract Pp digestion was increased. The lack of effect of phytase supplementation on dietary P utilization was probably because these late-lactation cows had a low P requirement and were fed P-adequate diets.     

Effects of feeding alfalfa stemlage or wheat straw for dietary energy dilution on nutrient intake and digestibility,growth performance,and feeding behavior of Holstein dairy heifers

Feeding high-quality forage diets may lead to excessive weight gains and over-conditioning for dairy heifers. Restriction of energy density and dry matter intake by using low-energy forages, such as straw, is a good approach for controlling this problem. Alfalfa stems contain high fiber and moderate protein content and have the potential to be used to replace straw to reduce dietary energy. The objective of this study was to compare nutrient intakes, digestibilities, growth performance, and feeding behaviors of dairy heifers offered an alfalfa silage/corn silage high-energy diet (HE; 13.1% crude protein, 65.4% total digestible nutrients, 39.7% neutral detergent fiber) with 2 energy-diluted diets that replaced various proportions of the corn or alfalfa silages with either alfalfa stemlage (STM; 12.6% crude protein, 59.1% total digestible nutrients, 46.4% neutral detergent fiber) or chopped wheat straw (WS; 12.6% crude protein, 61.9% total digestible nutrients, 43.7% neutral detergent fiber). Seventy-two pregnant Holstein heifers (16.8 ± 1.3 mo) were stratified into 3 blocks (24 heifers/block) by initial body weight (light, 440 ± 18.0 kg; medium, 486 ± 18.6 kg; heavy, 534 ± 25.1 kg), with each block composed of 3 pens (8 heifers/pen), with diets assigned randomly to 1 pen within the block. Diets were offered in a 56-d feeding trial. Both dry matter intake and energy intake were decreased with the addition of low-energy forages to the diets, but no differences in dry matter intake were observed across diluted diets. Digestibility of dry matter, organic matter, neutral detergent fiber, and apparent N were greater for HE compared with diluted diets, and for WS compared with STM. Total body weight gain (74 vs. 56 kg) and average daily gain (1.32 vs. 1.00 kg/d) were greater for heifers offered HE compared with diluted diets. Feed efficiency tended to be less for heifers offered the diluted diets compared with HE (10.7 vs. 8.6 kg of feed/kg of gain). Heifers did not sort for or against particles when offered HE. However, increased sorting behavior was observed for diluted diets. Compared with ad libitum feeding dairy heifers a diet with high nutrient content forages (corn silage and alfalfa silage), use of diet diluted with alfalfa stemlage or wheat straw is an effective feeding management strategy to control total daily dry matter and energy intake by increasing gut fill, and maintain desirable body condition and growth rates, even though the diluted diets had greater sortability.     

Effects of alfalfa hay inclusion rate on productivity of lactating dairy cattle fed wet corn gluten feed-based diets

An experiment was conducted to evaluate the effects of varying the alfalfa inclusion rate in diets containing 31% (dry matter basis) wet corn gluten feed (Sweet Bran, Cargill Inc.). Eighty primiparous and multiparous Holstein cows averaging 178 ± 90 d in milk (mean ± SD) were randomly assigned to 1 of 4 sequences in a 4 × 4 Latin square design with 28-d periods. Treatments were diets containing 0, 7, 14, or 21% alfalfa on a dry matter basis, with corn silage, corn grain, soybean meal, expeller soybean meal, and mineral supplements varying across diets to maintain uniform nutrient densities. Diets were formulated for similar crude protein, neutral detergent fiber, and nonfiber carbohydrate concentrations. Feed intake, milk production, body weight, and body condition score were monitored, and linear and quadratic effects of increasing the alfalfa inclusion rate were assessed using mixed model analysis. As the alfalfa inclusion rate increased, dry matter intake tended to increase linearly (26.7, 27.3, 27.4, and 27.5 kg/d for 0, 7, 14, and 21% alfalfa, respectively), and solids-corrected milk (29.9, 30.2, 30.8, and 30.5 kg/d) and energy-corrected milk production (32.9, 33.3, 33.8, and 33.6 kg/d) tended to increase linearly. Body weight gain decreased linearly (22.9, 18.0, 11.2, and 9.5 kg/28 d) with increasing alfalfa inclusion rate. Although increasing the inclusion rate of alfalfa increased the proportion of large particles in the diets, treatments had no effect on milk fat yield or concentration. Feeding more alfalfa (up to 21% of dry matter) tended to increase milk yield while decreasing body weight gain, suggesting that metabolizable energy utilization shifted from body weight gain to milk production in these treatments. However, adding alfalfa to the diet had only minor effects on productivity.     

Effect of phytase inclusion and calcium/phosphorus ratio on the performance and nutrient retention of grower–finisher pigs fed barley/wheat/soya bean meal‐based diets

Two experiments were conducted to evaluate the effects of phosphorus (P) level and calcium (Ca)/total P (tP) ratio on the efficacy of microbial phytase. Experiment 1 examined the effects of P concentration and microbial phytase inclusion on mineral excretion and pig performance, while experiment 2 examined the effects of Ca/tP ratio and microbial phytase inclusion on mineral excretion and pig performance. In experiment 1, nutrient and mineral digestibility (n = 4) and growth performance (n = 12) were determined in pigs individually fed diets containing (T1) 5.5 g kg^?1 tP, 2.3 g kg^?1 available P (aP) and 8.0 g kg^?1 Ca, (T2) 5.5 g kg^?1 tP, 2.3 g kg^?1 aP, 8.0 g kg^?1 Ca and 750 FYT kg^?1 Peniophora lycii phytase, (T3) 4.3 g kg^?1 tP, 1.4 g kg^?1 aP and 8.0 g kg^?1 Ca and (T4) 4.3 g kg^?1 tP, 1.4 g kg^?1 aP, 8.0 g kg^?1 Ca and 750 FYT kg^?1 P lycii phytase. In experiment 2, nutrient and mineral digestibility (n = 4) and growth performance (n = 12) were determined in pigs individually fed diets containing (TT1) 4.3 g kg^?1 tP and 8.0 g kg^?1 Ca, (TT2) 4.3 g kg^?1 tP, 8.0 g kg^?1 Ca and 750 FYT kg^?1 P lycii phytase, (TT3) 4.3 g kg^?1 tP and 5.0 g kg^?1 Ca and (TT4) 4.3 g kg^?1 tP, 5.0 g kg^?1 Ca and 750 FYT kg^?1 P lycii phytase. All diets were formulated, using standard feeding values for the ingredients, to have similar concentrations of digestible energy (DE) and lysine. In experiment 1, pigs offered the low‐P diets had significantly lower P intake (P < 0.001), faecal P excretion (P < 0.05), Ca intake (P < 0.05) and faecal Ca excretion (P < 0.05) compared with pigs given the adequate‐P diets. These pigs also had significantly lower daily gain (P < 0.01), feed intake (P < 0.05) and feed conversion ratio (FCR) (P < 0.05). The inclusion of phytase in both the adequate‐ and low‐P diets increased the digestibility of energy (P < 0.05) and Ca (P < 0.01) but had no effect on pig performance. In experiment 2, lowering the Ca/tP ratio from 1.85:1 to 1.15:1 increased the DE content of the diet (P < 0.05). The inclusion of phytase increased (P < 0.05) the digestibility of protein (0.874 versus 0.840, SEM 0.009) and Ca (0.427 versus 0.380, SEM 0.019) as well as the DE content of the diet (14.47 versus 14.26 MJ kg^?1, SEM 0.073). There was a significant ratio × phytase interaction (P < 0.5) for P digestibility. Microbial phytase significantly increased P digestibility when added to the 1.15:1 ratio diet but had no effect when added to the 1.85:1 ratio diet. The inclusion of microbial phytase increased feed intake (2.16 versus 2.00 kg day^?1, SEM 0.05; P < 0.05) and weight gain (0.893 versus 0.818 kg day^?1, SEM 0.022; P < 0.05). Lowering the Ca/tP ratio resulted in a significant improvement in FCR (2.32 versus 2.40 kg kg^?1, SEM 0.03; P < 0.05). In conclusion, the beneficial effects of microbial phytase supplementation of pig diets are adversely affected by a wide Ca/tP ratio. © 2002 Society of Chemical Industry     

Hydrothermal Cooking Affects Protein Efficiency Ratio and Zinc Bioavailability of Soymilk-Based Diets in Rats

Hydrothermally cooked (HTC) and conventionally processed soymilks were compared with respect to protein efficiency ratio (PER) and zinc bioavailability in Sprague-Dawley rats fed isocaloric, isonitrogenous diets. When dietary zinc was 50 mg/kg, PER (mean ± SD, n = 12) was greater for HTC (processed 20 sec) (2.69 ± 0.34) than for conventional soymilk (2.39 ± 0.17). When dietary zinc was 20 mg/kg, PER (n = 10) was less for HTC processed 40 sec (1.86 ± 0.17) than for conventional soymilk (2.08 ± 0.19). Processing (HTC vs conventional) did not affect zinc bioavailability by the slope ratio bioassay procedure. PER of HTC processed 20 sec was higher than that of reference casein and conventional soymilk when dietary zinc was near recommended levels; pancreatic hypertrophy was not observed.     

低有效磷饲粮添加植酸酶对肉仔鸡矿物质代谢的影响

100只艾维因肉仔鸡随机分为5组,每个组设4个重复。第1组喂标准饲粮;第2,3,4,5组喂低有效磷（0．20％）饲粮,分别加植酸酶0,350,500,650FTU／kg,饲养试验分两个阶段：0－3周,4－6周。试验期为5周,观察各组肉鸡的营养物质表观利用率、胫骨质量、血清化学指标的变化,研究低有效磷饲粮中添加植酸酶对矿物质代谢的影响及作用机制。试验结果表明：在低有效磷饲粮中添加植酸酶对矿物代谢有一定积极影响,以植酸酶最大添加量650FTU／kg组的效果为最佳。     

In-vitro and in-vivo dephosphorylation of rapeseed meal by means of phytate-degrading enzymes derived from Aspergillus Niger

A meal of ‘double low’ rapeseed (var ‘Jantar’) was subjected to phytate hydrolysis using enzyme preparations derived from a mycelium of Aspergillus niger which contained phytase (EC 3.1.3.8) and acid phosphatase (EC 3.1.3.2) activities. The complete conversion of myo-inositol hexa- and pentaphosphates present in rapeseed meal to lower phosphate esters of myo-inositol was accomplished at 40°C, a pH value of 4.5, phytase dosage (in phytase units (PhytU)) 0.1 PhytU g^?1 accompanied by acid phosphatase activity 37.1 units g^?1, in 1 h. Under these conditions, complete dephosphorylation was observed in 4 h. Decreasing the pH value to 3.0 caused a rise in the amount of inorganic phosphorus released, while increasing to 5.5 resulted in substantial reduction in the reaction rate. Purification of phytase to a specific activity 0.375 PhytU mg^?1 of protein exhibited a negative influence upon the yield of rapeseed dephosphorylation. The substitution of calcium phosphate for a preparation of phytase in feed containing rapeseed meal did not cause significant differences in the body weight gain or in tibia mineralisation of broilers (Gains galus, ‘Astra B’).     

丁酸钠对肉仔鸡生产性能及免疫功能的影响

试验选择体重基本一致的健康AA肉仔鸡300羽,随机分成5组:Ⅰ组(对照组)、Ⅱ组(250mg/kg丁酸钠)、Ⅲ组(500 mg/kg丁酸钠)、Ⅳ组(1 000 mg/kg丁酸钠)、Ⅴ组(40 mg/kg杆菌肽),每组6个重复,每个重复10羽,试验期21 d.试验结果表明:(1)14日龄采食量、增重、体重显著高于对照组(P<0.05),21日龄有增加趋势;14日龄料重比显著降低(P<0.05),21日龄有降低趋势.(2)14日龄和21日龄脾脏指数、胸腺指数、法氏囊指数有提高的趋势.(3)14日龄十二指肠上皮内淋巴细胞(IEL)数量显著高于对照组(P<0.05);21日龄十二指肠、空肠、回肠IEL数量均显著高于对照组(P<0.05).(4)14日龄十二指肠及回肠杯状细胞(GC)数量均显著高于对照组(P<0.05);21日龄空肠及回肠GC数量显著高于对照组(P<0.05).     

Influence of high dietary aluminum on performance and phosphorus bioavailability in dairy calves

Sixteen male intact Holstein calves averaging 72 kg and 64 d of age were used to study the effects of high dietary Al on calf performance and P bioavailability. The main effects were two concentrations of added aluminum (0 and .20% Al) and two of added P (0 and .22% P). The basal diet contained, by analysis, .132% P, .74% Ca, and .021% Al. The calves were assigned to four treatment groups balanced according to body weight. The four treatments were 1) normal P, low Al; 2) low P, low Al; 3) low P, high Al; and 4) normal P, high Al. Calved had ad libitum access to their respective diets for 7 wk. Metabolism of a single oral 32P dose was determined during wk 6. The adverse effects of high dietary Al include a 17% reduction in feed intake and a 47% reduction in body weight gains. Alkaline phosphatase and plasma glutamic oxaloacetate transaminase activities increased in calves receiving the high Al diets. A negative balance of P and Ca was noted in the calves fed high concentrations of Al. Apparent absorption of 32P was reduced (37%) in calved fed diets high in Al (44% of dose vs. 69%). Urinary excretion of 32P was not affected by dietary Al concentrations. Calves fed the low P (deficient) diet showed significant reductions in feed intake, weight gain, serum inorganic P, bone ash, and P content of bone. Dietary P did not significantly affect 32P absorption. Adding .20% dietary Al severely affects P metabolism and performance of young growing calves.     

日粮麦麸水平对3～6周龄肉鸡生产性能、养分利用及胫骨参数的影响

设计麦麸含量分别为0%、3%、6%、9%及9%麦麸+500IU/Kg微生物植酸酶的5种试验日粮, 诸日粮的主要营养成分相等。研究麦麸水平对肉鸡生产性能、养分表观利用率、血清生化指标及胫骨参数的影 响。结果表明,①3～6周龄肉鸡日粮含9%麦麸,可显著提高日粮干物质、总磷的表观利用率(p<0.05),日均 增重、血清钙磷含量、胫骨灰分含量与不含麦麸的对照组接近(p>0.05)。②含3%和6%麦麸,日均增重、日采 食量显著低于不含麦麸的对照组(p<0.05),料重比显著优于对照组(p<0.05)。③含6%～9%麦麸的日粮对 肉鸡生产有益。④正常磷水平下,日粮含9%麦麸时添加微生物植酸酶没有明显的作用。     

Comparison of full-fat corn germ, whole cottonseed, and tallow as fat sources for lactating dairy cattle

Twenty-four multiparous Holstein cows (124 ± 39 d in milk; 682 ± 72 kg of body weight) were used in 6 simultaneous 4 × 4 Latin squares to evaluate full-fat corn germ as a fat source for lactating dairy cows. Experimental diets were a control (containing 28% ground corn, 23% alfalfa hay, 19% wet corn gluten feed, and 10% corn silage, dry matter basis), and 3 diets with either whole cottonseed (WCS), tallow (TAL), or full-fat corn germ (FFCG) added to provide 1.6% supplemental fat. Cows were fed twice daily for ad libitum intake. Dry matter intake, milk yield, and energy-corrected milk did not differ among diets. Efficiency of milk production (energy-corrected milk/dry matter intake) was greater for cows fed WCS than for cows fed the control, TAL, or FFCG. Milk fat percentage from cows fed FFCG was less than that of cows fed WCS or the control, but was similar to that of cows fed TAL. Milk protein percentage was less for cows fed FFCG than for those fed the control. Total saturated fatty acids were less in milk from cows fed fat sources, and cows fed WCS and TAL had greater saturated fatty acids in milk than did cows fed FFCG. Unsaturated fatty acids were greater in milk from cows fed FFCG than in milk from cows fed the control, WCS, or TAL. The cis-9, trans-11 conjugated linoleic acid content was greater in milk from cows fed WCS, TAL, and FFCG than from cows fed the control, and it was greater in milk from cows fed FFCG than in milk from cows fed WCS or TAL. These results indicate that FFCG can be used effectively as a fat source in diets for lactating dairy cattle.     

Prepartum grain feeding and subsequent lactation forage program effects on performance of dairy cows in early lactation

One hundred fifty-six Holstein cows were balanced prior to drying off to one of three diets offered during the dry period (dry matter basis): A) forage only (50% corn silage:50% alfalfa silage), B) forage as A plus a standard dairy grain mix (1.73% calcium), and C) same as B except a low calcium grain mix (.35% calcium). Grain feeding started 3 wk prepartum. Cows from each dry treatment were assigned to one of two treatments during the first 21 d postpartum: total mixed ration (dry matter basis); 50% grain:50% corn silage; or 50% grain:25% corn silage:25% alfalfa silage. Dry period feeding program had no effect on postpartum dry matter intake, milk yield, or composition. Prepartum grain feeding resulted in increased body weight gain during the last 3 wk of the dry period. Feeding corn silage postpartum as the sole forage resulted in higher dry matter intakes (15.0 vs. 14.1 kg/d), milk production (31.3 vs. 29.7 kg/d), and less body weight loss (36 vs. 58 kg) during the first 21 d postpartum than feeding a 50% corn silage:50% alfalfa silage mixture. However, differences varied depending on dry cow feeding program. All dry cow treatments resulted in a high incidence of milk fever (11.5, 11.5, and 15.5% for A, B, and C, respectively). Dry cow rations containing as little as 50% alfalfa silage appear to predispose cows to increased incidence of milk fever.     

Effect of various levels of forage and form of diet on rumen development and growth in calves

The effect of form of starter grain (coarse vs. ground) and inclusion of various levels of hay on body weight gain and rumen development was evaluated. Two experiments were conducted to determine the effect of form of diet and forage inclusion on intake, growth, feed efficiency, and weaning age in dairy calves. Diets consisted of commercial coarse starter (C), ground starter (G), coarse starter with 7.5% bromegrass hay of consistent particle size (8 to 19 mm) (H1), and coarse starter with 15% hay (H2). In experiment 1, intake was held constant across treatments until weaning, when feed was offered ad libitum. Calves receiving H1 and H2 were heavier and had greater body weight gain and greater feed efficiency than calves receiving C. There were no differences in intake. Total volatile fatty acid concentrations were higher, and the proportion of acetate was lower for calves fed G vs. C. In experiment 2, calves (n = 56) were offered diets on an ad libitum basis and weaned according to intake. There were no differences in body weight gain, average daily gain, feed efficiency, and age at weaning with respect to treatment. Starter and total dry matter intake tended to be greater in calves fed H1 and H2 vs. C. The addition of controlled particle size hay to diets of young calves appears to favorably alter rumen environment, resulting in increased intake and improved feed efficiency. Forage of a consistent particle size can be successfully utilized in starter rations of young calves.     

Evaluation of Content and Source of Phosphorus Fed to Dairy Calves

Twenty-four Holstein bull calves, 12 Holstein heifer calves, and 6 Jersey bull calves were assigned to a 2 × 3 factorial experiment at 8 to 9 wk of age. Three concentrations (.26, .34, and .41%) and two sources (feed grades monoammonium phosphate and dicalcium phosphate) of dietary P were fed during a 10-wk trial. The biological availability of monoammonium phosphate was equal to dicalcium phosphate as a supplemental P source. Increasing dietary P from .26 to .34% increased feed intake, body weight gain, plasma inorganic P, plasma Mg, bending moment of the tibia and ninth rib, percentage ash, and ash content (P and Mg) of the 7th and 10th ribs and lowered plasma Ca. Only plasma inorganic P increased from .34 to .41%. Treatment means for .26, .34, and .41% P, respectively, were feed intake (kg.d⁻¹) 2.98, 3.48, and 3.34; daily body weight gain (kg.d⁻¹) .83, .94, and .92; wk 9 and 10 plasma inorganic P (mg-100 ml⁻¹) 6.08, 8.38, and 9.05; bending moment (kg.cm) of the 9th rib 31.6, 47.6, and 40.7 and tibia 1314.84, 1783.94, and 1751.00. These results indicate a requirement for calves greater than the .26% P currently recommended.     

Growth performance,feeding behavior,and selected blood metabolites of Holstein dairy calves fed restricted amounts of milk: No interactions between sources of finely ground grain and forage provision

The objective of this study was to investigate the effects of grain sources and forage provision on growth performance, blood metabolites, and feeding behaviors of dairy calves. Sixty 3-d-old Holstein dairy calves (42.2 ± 2.5 kg of body weight) were used in a 2 × 3 factorial arrangement with the factors being grain sources (barley and corn) and forage provision (no forage, alfalfa hay, and corn silage). Individually housed calves were randomly assigned (n = 10 calves per treatment: 5 males and 5 females) to 6 treatments: (1) barley grain (BG) without forage supplement, (2) BG with alfalfa hay (AH) supplementation, (3) BG with corn silage (CS) supplementation, (4) corn grain (CG) without forage supplement, (5) CG with AH supplementation, and (6) CG with CS supplementation. All calves had ad libitum access to water and starter feed throughout the experiment. All calves were weaned on d 49 and remained in the study until d 63. Starter feed intake and average daily gain (ADG) was greater for calves fed barley than those fed corn during the preweaning and overall periods. Calves supplemented with CS had greater final body weight and postweaning as well as overall starter feed intake than AH and non-forage-supplemented calves. During the preweaning and overall periods, feeding of CS was found to increase ADG compared with feeding AH and nonforage diets. However, feed efficiency was not affected by dietary treatments. Calves supplemented with CS spent more time ruminating compared with AH and control groups; nonnutritive oral behaviors were the greatest in non-forage-supplemented calves. Regardless of the grain sources, the rumen pH value was greater for AH calves compared with CS and non-forage-supplemented calves. Blood concentration of BHB was greater for CS-supplemented calves compared with AH and non-forage-supplemented calves. Furthermore, body length and heart girth were greater for calves fed barley compared with those fed corn, and also in forage-supplemented calves compared with non-forage-supplemented calves. These results showed no interactions between grain sources and forage provision on calf performance; however, the inclusion of CS and barley in starter diets could enhance the growth performance of Holstein calves during the transition from liquid to solid feed.     

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