Effects of the provision of large amounts of solid feeds to veal calves on growth and slaughter performance and intravitam and postmortem welfare indicators

Polish Friesian male calves (n = 78) were used to investigate the effects of innovative feeding plans based on the provision of large amounts of solid feeds on growth performance, welfare, and carcass characteristics of veal calves. Groups of calves (initial BW 71.5 ± 3.7 kg) were fed 1 of 3 treatments (26 calves/treatment): 1) milk replacer plus corn grain (CG), 2) milk replacer plus an 80:20 mixture (as-fed basis) of corn grain and wheat straw (CGS), or 3) milk replacer plus a 72:20:8 mixture (as-fed basis) of corn grain, wheat straw, and extruded soybean, respectively (CGSES). All the treatments provided at least 170 kg DM/calf from solid feed throughout the 206 d of fattening. Type and concentration of milk replacer were the same for all calves throughout fattening. Calves fed CGSES received 96% of the daily amount of milk replacer delivered to CG and CGS to balance the dietary CP content. No differences (P ≥ 0.063) among treatments were observed for growth performance and DMI. Health status of CG calves was less than CGSES calves, as indicated by the greatest (P < 0.001) proportion of milk replacer refusal events and the greatest (P < 0.001) incidence of treatments for respiratory disorders. Inclusion of straw and soybean in the solid feeds increased (P < 0.001) the daily intake of iron in CGS and CGSES as compared with CG; however, blood hemoglobin concentrations measured at d 5 and 31 were greater (P < 0.05) than when measured on d 80, 122, and 206 of fattening. Feeding treatment did not (P ≥ 0.107) affect HCW, dressing percentage, or carcass color. Calves fed CG had heavier (P < 0.001) reticulorumens and more (P < 0.001) developed rumens than CGS and CGSES calves, but 84% and 68% of CG rumens (P < 0.001) showed overt signs of hyperkeratinization and plaques, respectively. These alterations of rumen mucosa were not detected in CGSES calves, and only 8% of CGS calves had rumen plaques. Regardless of feeding treatment, postmortem inspection recorded a prevalence of more than 84% abomasal lesions. When feeding veal calves with large amounts of solids, it is advisable to avoid the provision of corn grain alone and replace part of the cereal with a roughage source to improve calf health and prevent rumen mucosa alterations.     

Resistance of neonatal calves given colostrum diet to oral challenge with a septicemia-producing Escherichia coli.

Twenty Holstein-Friesian male calves were obtained within 4 hours after bith (colostrum deprived) and allotted to 1 of 4 groups, each given a different feeding: colostrum, milk replacer, polyvinylpyrrolidone (PVP), and saline solution (0.85% NaCl). Each calf was fed 2 L of the respective diets every 12 hours. Rectal temperatures were recorded and blood samples were collected immediately before each feeding. At approximately 27 hours of age, all calves were inoculated orally with 1.5 X 10(10) viable organisms of a septicemia-producing Escherichia coli serotype O26: K60:NM. Within 8 hours, all calves had diarrhea. Coli-septicemia (E coli cultured from liver, spleen, and cardiac blood) was present in 1 of the 5 calves fed colostrum, in 5 or the 5 calves fed milk replacer, in 5 of the 5 calves fed PVP, and in 4 of the 5 calves fed saline solution. At necropsy of the calves (12 to 48 hours after oral inoculation), the same organism was isolated by cultural technique from small intestines of 19 of the 20 calves. Serum immunoglobulin G concentrations increased (P less than 0.01) in calves fed the colostrum diet in sharp contrast to the agammaglobulinemia occurring in calves fed the milk replacer, PVP, or saline solution. Results indicate that colostrum fed to the calf soon after birth provides protection from colisepticemia, but does not prevent the diarrhea of colibacillosis.     

Comparison of two oral electrolyte solutions for the treatment of dehydrated calves with experimentally-induced diarrhoea

We compared the ability of two oral electrolyte solutions to resuscitate calves with experimentally induced diarrhoea and dehydration. Sucrose solution, furosemide, spironolactone, and hydrochlorothiazide were administered to 18 male Holstein-Friesian calves to induce diarrhoea and dehydration. Clinical changes after 24 h included severe diarrhoea, moderate dehydration (8-10% body weight), azotemia, and clinical depression. Calves were then randomly assigned to one of three treatment groups (milk replacer, 2 L every 12 h; hyperosmotic oral electrolyte solution, 2 L every 12 h; iso-osmotic oral electrolyte solution, 1.5 L every 6 to 12 h) and followed for an additional 48 h.Compared to feeding milk replacer, the hyperosmotic solution significantly (P< 0.05) improved hydration status, increased body weight, maintained urine production, decreased the degree of clinical depression and prevented development of metabolic acidosis, although serum glucose concentration was decreased at 24 h and 48 h. The hyperosmotic solution produced a similar resuscitative response to the iso-osmotic solution, but maintained higher serum glucose concentrations and lower serum beta-OH butyrate and non-esterified fatty-acid concentrations, indicating that the hyperosmotic solution provided greater nutritional support. The hyperosmotic solution rehydrated calves faster and more effectively than feeding equivalent volumes of milk replacer and can, therefore, be recommended as part of the initial treatment of dehydrated calves with diarrhoea.     

Thirty or sixty percent milk replacer reduction for calves: effects on alfalfa hay intake and digestibility, digestive kinetics and ruminal fermentation

Twelve artificially reared, male Holstein calves, ruminally cannulated at 53 d of age, were used in a split-plot design to study the effects of no milk replacer reduction (CON), or reduction by 30% (30R) or 60% (60R) of this value on alfalfa hay intake and digestibility, ruminal fermentation and digestive kinetics. Milk replacer reduction began at 53 d of age and continued until 135 d of age, after which no milk replacer was fed. All calves had ad libitum access to long-stemmed alfalfa hay from birth. Five collection periods were conducted at average calf ages of 72, 87, 108, 129 and 151 d. Reducing the amount of milk replacer fed resulted in a linear increase (P less than .05) in forage OM intake; however, total OM intake (forage + milk) was not different (P greater than .10) among milk reduction groups. Size of particles in feces exhibited quadratic effects in response to milk replacer reduction (P less than .05) but only in the small (less than 150 microns) size groupings. Ruminal pH and ammonia and individual VFA concentrations (except isobutyrate) were not altered by milk reduction (P greater than .10) but increased (P less than .01) with calf age. Milk replacer reduction had a quadratic effect (P less than .05) on fluid outflow rate from the rumen, increasing as milk replacer was reduced. Other fluid and particulate kinetic data, as well as NDF digestion rate and DM digestion showed no effects (P greater than .10) from milk replacer reduction but changed with calf age. Milk replacer reduction increased forage intake but had minimal effects on digestive variables evaluated, suggesting that intake of milk replacer by calves can be reduced by up to 60% without disturbing forage fermentation and passage.     

The effects of feeding milk to diarrheic calves supplemented with oral electrolytes.

The effects of feeding different levels of milk to diarrheic calves (n = 19) supplemented with oral electrolytes were investigated. In the early stages of the disease the calves were fed either enough milk to maintain normal growth in a healthy calf, one half that volume or no milk. The three groups were further subdivided according to whether or not the electrolyte solution contained bicarbonate. A full milk ration allowed uninterrupted weight gains of 1% body weight/day (p = 0.003), but caused greater inappetence (p = 0.003 to 0.037) at the beginning of the trial than lower levels of milk intake. Electrolyte solutions with bicarbonate reduced growth rates in milk fed calves (p = 0.014). The density of fat stores increased with the level of milk feeding (p = 0.04 to 0.053). The mitotic index of the duodenal mucosa increased with milk feeding (p = 0.08), indicating a superior mucosal regeneration potential. Thymic atrophy was pronounced in those calves fed no milk (p = 0.001). It was concluded that the continued feeding of milk to diarrheic calves was beneficial. Electrolyte solutions containing bicarbonate should be avoided when milk is fed to diarrheic calves.     

不同代乳品及饲喂方式对荷斯坦奶公犊生产犊牛白肉影响的研究

为研究代乳粉(主要含乳类制品)液态饲喂和代乳料(主要含植物类饲料等)干喂对荷斯坦奶公犊生产犊牛白肉的影响,试验选用20头健康无病、体重和出生日期相近的荷斯坦奶公犊,随机分为2组,每组10头,进行了120 d的生长育肥试验。Ⅰ组饲喂市售的代乳粉(粗蛋白质22%,粗脂肪16%);Ⅱ组饲喂配制的代乳料(粗蛋白质22%,消化能16 MJ/kg)。结果表明:①Ⅱ组犊牛0~90 d平均日增重高于Ⅰ组犊牛,91~120 d平均日增重显著低于Ⅰ组犊牛(P< 0.05),但两组犊牛0~120 d平均日增重和试验末重均无显著差异(P> 0.05)。②不同代乳品及饲喂方式对奶公犊营养物质表观消化率均无显著影响(P> 0.05)。③Ⅰ组犊牛的胴体重、屠宰率和眼肌面积均显著高于Ⅱ组犊牛(P< 0.05),分别比Ⅱ组高11.88%、11.04%和8.12%,但两组间的胴体产肉率无显著差异(P> 0.05);两组犊牛背最长肌的pH、剪切力、蒸煮损失和肉色均无显著差异(P> 0.05),但Ⅰ组犊牛的失水率比Ⅱ组犊牛高20.83%(P< 0.01);Ⅰ组犊牛背最长肌中粗脂肪含量极显著高于Ⅱ组犊牛(P< 0.01),但两组犊牛背最长肌中水分、粗蛋白质、粗灰分、钙、磷和铁的含量均无显著差异(P> 0.05)。④Ⅱ组犊牛的饲养成本比Ⅰ组降低45.38%。综上所述,饲喂代乳料的犊牛可获得与饲喂代乳粉犊牛相似的生长性能和肉品质,显著降低饲养成本。     

Modification of the concentration of creatinine and sodium in blood serum and urine and the fractional elimination of sodium by electrolyte therapy in calves]

In 32 calves, creatinine and sodium concentrations were determined in blood and urine samples taken simultaneously four times during two periods of two days each (control period: milk or milk replacer; trial period: oral electrolyte solution). Creatinine urine/serum ratios and fractional elimination of sodium (FENa) were calculated. The influence of the type of liquid feed on these parameters was evaluated statistically. Calves fed milk replacer had higher urine sodium concentrations and FENa than calves fed whole milk. All parameters determined were influenced by intake of oral electrolyte solution: creatinine concentrations in serum and urine decreased, whereas sodium concentrations in serum and urine, as well as FENa, increased. It is concluded that sodium content of liquid feed significantly influences FENa.     

Study on Production of White Veal with Holstein Bull Calves Fed on Different Milk Replacer and Feeding Methods

The objective of this experiment was to study the effects of production of white veal with Holstein bull calves fed on the liquid milk replacer (containing mainly dairy products) feeding and the dry milk replacer (containing mainly plant diet, etc)feeding.20 healthy male calves with similar birth date and body weight were selected, and randomly divided into two groups (10 calves per group), for a period of 120 d white beef production fattening test.GroupⅠfed with milk replacer (commercial, 22% CP, 16% EE), groupⅡ fed with milk replacer (formulated, 22% CP, 16 MJ/kg DE).The results showed as follows:① 0 to 90 d ADG of group Ⅱ were higher than groupⅠ, 91 to 120 d ADG of group Ⅱ were significantly lower than groupⅠ (P< 0.05), but there were no significant differences in 0 to 120 d ADG and 120 d weight between two groups (P> 0.05).② There were no significant differences in the nutrient apparent digestibility of Holstein bull calves with different milk replacer and feeding methods (P> 0.05).③ Carcass weight, dressing percentage and eye muscle area of groupⅠcalves were significantly higher than those of group Ⅱ (P< 0.05), increased by 11.88%, 11.04% and 8.12%, respectively, but there was no significant difference in carcass meat production rate between two groups (P> 0.05).There was no significant differences in pH, shear force, cooking lose and meat color of longissimus between two groups (P> 0.05), but compared with group Ⅱ, the water lose rate of groupⅠincreased by 20.83% (P< 0.01).The content of EE of groupⅠwas significantly higher than group Ⅱ (P< 0.01), but there were no significant differences in the contents of moisture, CP, Ash, Ca, P and Fe of longissimus between two groups (P> 0.05).④Compared with groupⅠ, the feed cost of group Ⅱ was reduced by 45.38%.In summary, the growth performance and meat quality of two groups calves were similar, feeding cost was reduced significantly.     

代乳粉对早期断奶犊牛生长的影响

旨在评价饲喂代乳粉对早期断奶犊牛生长及培育成本的影响。选取体重相近的新生犊牛45头,随机分为试验1组、试验2组和对照组;试验1组饲喂A品牌代乳粉,试验2组饲喂B品牌代乳粉,对照组饲喂牛场产鲜牛奶;测定各组实验犊牛的出生体重、1月龄体重和50日龄断奶体重;计算并比较各组犊牛培育成本。结果表明,各组犊牛的出生体重和1日龄体重差异不显著（P〉0.05）;试验1组和试验2组犊牛的50日龄断奶体重分别比对照组增加5.12、2.86 kg,且试验1组与对照组相比差异显著（P〈0.05）;试验1组和试验2组犊牛的平均日增重分别比对照组增加0.14、0.07 kg,且试验1组和对照组相比差异显著（P〈0.05）;试验1组与试验2组平均每头犊牛分别比对照组节约饲养成本198.8、222.0元。综上提示,使用代乳粉能够促进犊牛生长,降低犊牛的培育成本,提高养殖场的经济效益。     

复合酸度调控剂对犊牛生长性能、血气指标的影响

探讨代乳粉中添加复合酸度调控剂对0～3月龄犊牛生长性能、血气指标的影响。试验分为对照组和试验组,分别饲喂乳液pH值为6.2和5.0的代乳粉。每个处理6头犊牛,分别在试验开始后的0、14、28、42、56d测定每头犊牛的体重、体尺,每日记录每头犊牛代乳粉和开食料供料量和剩料量,观察每头犊牛的粪便形态和评分,并分别在0、14、42d采血测定血气指标。试验数据显示:与对照组相比,试验组犊牛各阶段的平均日增重有所提高,其中0～14、14～28、28～42、42～56d分别提高了5.6%、45.9%(P<0.05)、11.9%、5.8%;试验全期两组间平均日采食量、饲料转化率差异皆不显著(P>0.05);全期腹泻率试验组比对照组降低了13.9%,但差异不显著(P>0.05);28d体长指数试验组低于对照组(P<0.05)。试验开始(0d)和饲喂42d时各组间犊牛血气指标皆无差异(P>0.05);饲喂14d时试验组血液的pH值(P<0.05)、氧饱和度(P<0.05)、氧气分压、实际剩余碱储、标准碳酸氢盐浓度皆高于对照组,而二氧化碳分压显著低于对照组(P<0.05)。结果表明,在代乳粉中添加复合酸度调控剂后28d前对犊牛产生了一定作用,可提高14～28d阶段犊牛日增重,降低28d体长指数,并有降低腹泻率的趋势;犊牛血液的pH值、SO2升高而PCO2降低。     

犊牛代乳粉对早期断奶犊牛生长发育的影响

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

Economic analysis of feeding pasteurized nonsaleable milk versus conventional milk replacer to dairy calves

OBJECTIVE: To determine growth, morbidity, and mortality rates in dairy calves fed pasteurized nonsaleable milk versus commercial milk replacer and compare economics of feeding pasteurized nonsaleable milk versus commercial milk replacer in dairy calves. DESIGN: Clinical trial. ANIMALS: 438 dairy calves. PROCEDURE: Calves were assigned at 1 to 2 days of age to be fed pasteurized nonsaleable milk or a commercial milk replacer until weaned. Body weight was measured at the time of study enrollment and at the time of weaning, and any medical treatments administered and deaths that occurred prior to weaning were recorded. A partial budget model was developed to examine the economics of feeding pasteurized nonsaleable milk versus commercial milk replacer. RESULTS: Calves fed conventional milk replacer had significantly lower rates of gain (-0.12 kg/d [-0.26 lb/d]), lower weaning weights (-5.6 kg [-12.3 lb]), higher risk for treatment during the summer and winter months (odds ratio [OR], 3.99), and higher risk of death during the winter months (OR, 29.81) than did calves fed pasteurized nonsaleable milk. The estimated savings of feeding pasteurized nonsaleable milk, compared with milk replacer, was dollars 0.69/calf per day. The estimated number of calves needed to economically justify the nonsaleable milk pasteurization system was 23 calves/d. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that dairy calves fed pasteurized nonsaleable milk have a higher growth rate and lower morbidity and mortality rates than do calves fed conventional milk replacer. Feeding pasteurized nonsaleable milk could be an economically viable strategy for dairy calf producers.     

Clinical efficacy of chlortetracycline hydrochloride administered in milk replacer to calves

Two similar groups of 14 calves were housed and fed identically in individual pens on a calf-rearing farm. The groups were balanced for weight and immunological status as determined by zinc sulphate turbidity values. When an outbreak of enteric and respiratory disease occurred one group was treated with 20 mg chlortetracycline hydrochloride/kg bodyweight daily for seven consecutive days, by adding the active ingredient to the milk replacer, while the other group was left untreated. Both groups received additional therapy as required. The calves were examined daily during the period of treatment and the clinical observations were assessed and analysed statistically. There was a significant difference between the clinical scores of the two groups on the second day of treatment (P less than 0.05) and on all subsequent days (P less than 0.01) indicating that the calves receiving chlortetracycline hydrochloride were less affected by the disease outbreak. The abnormal enteric and respiratory signs were associated with several potential pathogens including bacteria, viruses and protozoa. The treatment was therefore effective against enteric and respiratory disease involving several organisms.     

Indigestion in Young Calves. V. The Influence of Grass Silage and Fine Hay

In an experiment with 24 young calves, lasting 45 days, all were fed a high lactose milk replacer causing some diarrhoea. Eight calves received grass silage and 8 fine hay in addition, while 8 received no solid supplement to the milk replacer (NS). Somewhat more (P < 0.05) dry matter was ingested from silage than hay. Weight gain was similar on the 2 supplements and much greater (P < 0.001) than on NS. Both silage and fine hay reduced (P < 0.01) the frequency of diarrhoea, approximately to the same extent. Further, silage or hay gave higher pH (P = 6.0.01 and 0.02, respectively) and less gram positive cocci and rods in the rumen fluid, better developed ruminai papillae and heavier (P < 0.01) empty reticulo-rumens than NS. Some calves fed silage had ulcers in the rumen, the same having occurred on fine hay in earlier experiments, but not in the present one. Althogether, the 2 roughages gave very similar results.     

The provision of solid feeds to veal calves: I. Growth performance, forestomach development, and carcass and meat quality

Growth performance, forestomach development, and carcass and meat quality of veal calves fed a milk replacer diet (Control) were compared to those obtained from calves fed the same liquid diet plus 250 g x calf(-1) x d(-1) of dried beet pulp or wheat straw. Three groups of 46 Polish Friesian calves, balanced according to initial BW, were assigned to the three dietary treatments in a fattening trial, which lasted 160 d. The provision of either solid feed did not affect the milk replacer intake. However, calves' ADG was increased (P < 0.01) only by feeding the beet pulp diet. The administration of both solid feeds improved calves' health status; calves fed solid feeds required fewer iron treatments for low hemoglobin and needed less medical treatments for respiratory or gastrointestinal diseases. In comparison to the Control calves, the provision of wheat straw and beet pulp increased iron intake throughout the fattening period by 41 and 130%, respectively. However, only calves fed beet pulp showed higher levels of hemoglobin and plasma iron concentrations (P < 0.05), whereas the same blood parameters were similar between Control calves and those fed wheat straw. At slaughter, both solid feeds led to empty forestomach weights heavier than those of Controls without reducing dressing percentage. The reticulorumen was heaviest in calves fed beet pulp, whereas wheat straw promoted omasal development. The administration of beet pulp resulted in a better carcass conformation than did the Control diet or wheat straw, but it had a detrimental effect on carcass color, which was graded as the darkest (P < 0.001). Consistent with this result, meat color of calves fed beet pulp was darker than that of Control calves and those fed wheat straw, because of the higher hematin concentration measured at the muscle level. No differences in carcass and meat color were observed between Control calves and calves fed wheat straw. The administration of solid feeds for welfare purposes does not always prevent the production of veal meat fulfilling the color standards required by the market. There is not a straight-forward relationship between a solid feed's iron content and the "redness" of veal meat, which should be related to the capability of the calves to use the iron provided by the roughage.     

The effect of biotechnological treatment of milk-replacer feeding mixtures on hematologic and biochemical parameters and its utilization in calves

A trial was performed with cellulase administration (3 cx per g of ingested feed dry matter) to early weaned calves fed minimum amounts of milk replacer (21 kg per milk nutrition period) and sweet (C, D) and sour (A, B) diets. The groups B and D were supplemented with an enzyme till the age of 90 days. The calves were given free choice of COT concentrate mixture, hay and water. Liveweight gains, feed and nutrient intake and health condition of calves were the characteristics investigated in this trial. Hematocrit value, hemoglobin, glucose and urea contents were determined in blood, in blood plasma buffer capacity was investigated. Although the differences in calf performance are not statistically significant, the best growth of calves in the vegetable nutrition period was observed in calves in group D. Nutrient conversion was also higher in calves of group D in the vegetable nutrition period. In conversion of nutrient consumption per 1 kg liveweight gain the difference in the intake of digestible crude protein and starch units between the group of calves fed sweet milk without enzyme addition in the milk nutrient period (A--digestible crude protein 0.40 +/- 0.005; starch units 1.74 +/- 0.008) and group D (sour diet + 3 cx cellulase--digestible crude protein 0.34 +/- 0.007; starch units 1.52 +/- 0.044) was statistically significant (P less than 0.025 and P less than 0.05) in favour of group D. An analysis of the results of hematological and biochemical investigations during the trial demonstrates that the sour diet is better in view of changes in glucose concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of suckling an isotonic solution of sodium acetate, sodium bicarbonate, or sodium chloride on abomasal emptying rate and luminal pH in calves

OBJECTIVES: To compare abomasal emptying rates in calves after suckling milk replacer or 3 common orally administered electrolyte solution components. ANIMALS: 5 male calves < 35 days of age. PROCEDURES: Calves with a cannula fitted in the abomasal body were fed 2 L of milk replacer with or without parenteral administration of atropine (0.01 mg/kg, i.v., then 0.02 mg/ kg, s.c., q 30 min) or isotonic (150 mM) solutions of sodium acetate, NaHCO(3), or NaCl in a randomized crossover design. Abomasal emptying rates were determined via scintigraphy, acetaminophen absorption, ultrasonography, and change in abomasal luminal pH. RESULTS: Scintigraphic half-emptying time, time of maximal plasma acetaminophen concentration, ultrasonographic half-emptying time, and pH return time indicated similar abomasal emptying rates following suckling of isotonic sodium acetate, NaHCO(3), and NaCl solutions, whereas the emptying rate of milk replacer was significantly slower. Mean maximal abomasal luminal pH was highest following suckling of NaHCO(3) (pH(max)=7.85) and lowest following suckling of NaCl (pH(max)=4.52); sodium acetate (pH(max)=6.59) and milk replacer (pH(max)=5.84) yielded intermediate pH values. CONCLUSIONS AND CLINICAL RELEVANCE: Isotonic solutions of sodium acetate, NaHCO(3), and NaCl were rapidly emptied from the abomasum but varied markedly in their ability to alkalinize the abomasum. Sodium bicarbonate-containing orally administered electrolyte solution might increase the frequency of infection or severity of clinical disease in diarrheic calves treated for dehydration by causing prolonged abomasal alkalinization.     

Digestibility and blood parameters in the preruminant calf fed a clotting or a nonclotting milk replacer

Eight male Holstein calves 7 to 10 d of age were fed a milk replacer containing a skim milk powder subjected to low-temperature drying either with or without addition of an oxalate-NaOH buffer known to prevent curd formation. The calves were used in a completely randomized design to study the effect of milk clotting on digestibility and blood parameters. Plasma glucose and plasma insulin were similar (P greater than .05) for the clotting and the nonclotting milk replacers. For both treatments, concentrations of glucose and insulin reached a peak 2 h postfeeding (P less than .01). Plasma triglycerides were higher (P less than .01) postfeeding for the nonclotting than for the clotting milk replacer. Plasma essential amino acids and plasma urea were higher, whereas plasma calcium was lower, for the nonclotting milk (P less than .01). Digestibility of dry matter, protein and fat was similar (P greater than .05) between clotting and nonclotting milk. The dry matter content of feces was not affected by clotting (P greater than .05). The data are interpreted to indicate that clotting of the milk replacer modifies blood concentrations of triglycerides, essential amino acids and urea without changing the digestibility of the diet.     

饲喂不同营养水平代乳粉对犊牛生长性能的影响

选择体重和出生日期相近、健康状况良好的荷斯坦公犊牛30头,随机分为3组（试验I组、Ⅱ组和Ⅲ组）,每组10头,研究了饲喂不同脂肪和蛋白质水平代乳粉对犊牛生长性能的影响。不同处理代乳粉的营养水平分别为：试验I组,EE13％、CP22％;Ⅱ组,EE16％、CP24％;Ⅲ组,EE19％、CP26％。研究结果表明．犊牛的日增重随着代乳粉营养水平的升高逐渐提高,试验Ⅱ组和Ⅲ组的日增重分别比试验I组提高了35．45％和37．63％（P〈（1．05）．试验Ⅱ组和Ⅲ组的平均日增重差异不显著;饲喂高营养水平代乳粉具有降低犊牛腹泻的趋势;不同试验处理对犊牛开食料采食量无显著差异。综合分析饲喂不同营养水平代乳粉对犊牛生长和经济效益的影响,代乳粉的适宜营养水平为EE16％、CP24％。     

代乳粉在犊牛早期断奶技术中应用的试验研究

22头体重相近的荷斯坦犊牛随机分为2组,试验组饲喂代乳料,对照组饲喂新鲜牛奶。经60d的饲喂试验发现,试验组增重比对照组多5.3kg/头,且差异极显著(P<0.01),日增重比对照组提高了88.3g/d,差异极显著(P<0.01)。