Two-hundred nine sows were used in a 2 • 2 spl i t -plot unbalanced design to measure the effect of folic acid against control, and flushing against a normal level of feeding, between weaning and mating on the following variables: serum folates at weaning and at 60 d of gestation, blood hemoglobin (Hb) and hematocri t (Ht) after 15 wk of gestation and reproductive performance at farrowing. Folic acid was administered im according to a schedule that maintained serum folates at approximately the same level between weaning and 60 d of gestation. The treatments had no effect on Hb or Ht after 15 wk of gestation. Average live l i t ter size was 12.0 piglets/litter for sows receiving the folic acid and flushing treatments as compared with 10.5 for sows without any treatment; the main effect of folic acid was significant (P~z.04). Intrali t ter variation in birth weight and total l i t ter weight tended to be increased by folic acid administration. Results showed that the administration of folic acid during gestation could appreciably improve the reproductive performance of sows. (

Fifty-one Outaouais Arcott ewes were used to study the effects of silage maturity, protein level and number of lambs suckled on milk production and lamb growth in a 2 × 2 × 2 factorial design experiment. Ewes were given ad libitum access to either an early-bloom (EB) or full-bloom (FB) bromegrass silage supplemented with 725 g d−1 of a 15 or 21% CP concentrate. Number of lambs suckled were two or three per ewe. During the 6 wk of lactation, ewes receiving the EB silages consumed more DM (2.07 vs. 1.74 kg d−1, P < 0.01), and gained more (1.3 and −2.7 kg, P < 0.05) than ewes fed FB. Ewes that raised three lambs had greater silage intake (2.00 vs 1.86 kg d−1) and lost more weight during lactation (−2.8 vs. +0.3 kg) than those suckling twins. Milk yields of ewes offered the EB and FB silages were 2.42 and 2.28 kg d−1, respectively (P < 0.05), for the first 4 wk of lactation. Ewes that raised three lambs produced less milk (2.25 vs. 2.43 kg d−1) than those nursing twins (P < 0.05). Milk fat content (8.2%) was not influenced by treatments, whereas milk protein content was higher (P < 0.05) from ewes receiving the EB silage compared with the FB silage (5.05 vs. 4.76%). At 4 and 6 wk of age, twin lambs were 2.6 kg (9.5 vs. 6.9 kg) and 3.5 kg (12.0 vs. 8.5 kg) heavier (P < 0.01) than triplet lambs for EB and FB silages, respectively. However, at the end of the 6-wk period, ewes nursing triplets weaned 1.3 kg more lambs than did ewes nursing twins (P < 0.05). Lambs from ewes that received the EB silage were 1.1 kg heavier at 6 wk (P < 0.05) than those from ewes fed with the FB silage. Also, lambs from ewes receiving the 21% CP concentrate were 1.1 kg heavier at 6 wk (P < 0.05) than the lambs from ewes fed the 15% CP. Litters were heavier at 6 wk with 21% CP concentrate compared with 15% (25.1 vs. 24.1 kg, P < 0.05), and triplet litters were heavier (P < 0.01) than twin with the EB silage. Within litter weight variation (weight difference between the biggest and the smallest lambs in a litter) proved to be greater (P < 0.05) with triplets (4.2 kg) than twins (2.2 kg). In conclusion, providing a higher quality silage (lower ADF and higher CP contents) improved ewe feed intake, milk production, lamb growth and litter weight, while feeding a higher protein concentrate only improved lamb growth with the lower quality silage. Key words: Ewe, lamb, growth, milk production, silage, protein, triplet

Holstein cows (n = 24) averaging 42 d in milk were used in a randomized complete block design during a 4-wk trial. A control total mixed ration (TMR) was compared with TMR supplemented with Ca salts of fatty acids from canola oil, soybean oil, or linseed oil. The three vegetable oils were progressively more unsaturated; the dominant fatty acids were, respectively, cis-delta-9-C18:1, C18:2, and C18:3. Apparent total tract digestibility of dry matter, crude protein, ether extract, and neutral detergent fiber was higher for rations containing Ca salts than for the control ration. Milk yield increased linearly as the unsaturation of the dominant fatty acid in the Ca salts increased. Milk fat percentage was reduced when Ca salts were added to the rations. The addition of Ca salts to the ration decreased the proportions of saturated fatty acids that contained C6 to C16 and increased the proportions of C18:0, cis-delta-C18:1, and trans-delta-11-C18:1 in milk fat. Proportions of C18:2 and C18:3 increased linearly, and cis-delta-9-C18:1 decreased linearly, as the unsaturation of the dominant fatty acid in the Ca salts increased. The proportion of fat that was liquid at 5 degrees C was higher for butter from cows fed diets containing Ca salts, but the proportion of liquid fat at 20 degrees C was not affected. Calcium salts of unsaturated fatty acids added to the diets of dairy cows improved the thermal properties of milk fat.

Ten Holstein cows in early lactation were used in a replicated 5 × 5 Latin square design to study the effects of MgO and three buffers added to diets containing Ca salts of canola oil fatty acids. Treatments were 1) control (basal diet; no buffer), 2) 1.1% NaHCO3 plus 1.1% KHCO3, 3) 1.9% NaHCO3,4) 0.5% MgO, and 5) 2.0% Na sesquicarbonate (percentage of dry matter). The control diet contained 53% grass silage, 43% concentrate, and 4% Ca salts. Body weight, intake, milk yield, and percentages of milk fat, protein, and lactose were unaffected by treatments. Buffers and MgO tended to increase triacylglycerol extraction by the mammary gland and changed the proportions of some fatty acids in milk. Arterial concentrations of acetate and triacylglycerol were correlated with their respective arteriovenous differences. Extraction by the mammary gland was high for acetate (≈58.2%), triacylglycerol (≈47.3%), propionate (≈34.6%), and glucose (≈24.3%). Extraction of free fatty acids, phospholipids, or cholesterol was negligible. Mammary triacylglycerol arteriovenous difference tended to be higher when MgO was fed than when NaHCO3 was fed. Sodium sesquicarbonate, NaHCO3, and the blend of bicarbonate buffers increased C18:2 in milk fat when compared with the control treatment. The concentration of C18:2 in milk fat decreased when MgO was fed, but the ratio of cis-C18:1 to trans-C18:1 increased compared with effects of dietary NaHCO3. Medium-chain fatty acids in milk fat tended to be higher with Na sesquicarbonate than with NaHCO3. Buffers and MgO modified the profiles of fatty acids in milk.

Holstein cows (n = 24) averaging 39 d of lactation were used in a randomized complete block design during an 8-wk trial. From wk 1 to 4, diets contained 62% alfalfa silage and 38% concentrates (dry matter basis), and, from wk 5 to 8, diets contained 47% forage and 53% concentrates. The concentrates were increased for the second phase so that the effect of bicarbonates could be expressed more fully. Diets 1, 2, and 3 contained 2% of a blend of Na and K bicarbonates and 0, 2, or 4% of Ca salts of canola oil fatty acids (percentage of dry matter), respectively. Diet 4 contained the same percentage of Ca salts as did diet 3 but without bicarbonates. Dry matter intake decreased linearly (wk 4), and milk yield was altered quadratically (wk 4), as the percentage of Ca salts in the diet increased. Milk fat percentage (wk 8) and yield (wk 4 and 8), as well as milk protein percentage (wk 4 and 8) and yield (wk 4), decreased linearly as the percentage of Ca salts in the diet increased. Short- and medium-chain saturated fatty acids decreased linearly, and C18:0, trans-delta-11-C18:1, cis-delta-9-C18:1, cis-delta-11-C18:1, and C18:2 increased linearly, as Ca salts in the diet increased. Addition of Na and K bicarbonates to the diets that contained Ca salts increased milk and milk protein yields and increased the proportions of C18:2 in milk fat at wk 8. Dietary bicarbonates had no effect on the responses of other milk fatty acids to supplementation of 4% Ca salts of canola oil fatty acids.

Twenty-four multiparous Holstein cows (48 d in lactation) were used in an 8-wk trial employing a completely randomized block design to determine the effect of heat treatment of full fat soybeans on the fatty acid composition of milk fat. Treatments consisted of a total mixed ration supplemented with 1) ground raw, 2) extruded, 3) micronized, or 4) roasted soybeans included at 17.5% of the dry matter of the total mixed ration. Dietary treatment had no effect on body weight, yields of milk or solids-corrected milk, fat percentage, or yield of milk fat or protein. Cows fed ground raw soybeans had a higher dry matter intake and a higher percentage of protein in milk than those fed heat-treated soybeans. The concentrations of saturated fatty acids from C8:0 to C16:0 were lower, and cis-delta-9-C18:1 tended to be higher, in the milk fat of cows fed heat-treated soybeans than in the milk fat of cows fed ground raw soybeans. The concentration of trans-delta-11-C18:1 was lowest for cows fed ground raw soybeans, intermediate for cows fed micronized and roasted soybeans, and highest for cows fed extruded soybeans. Cows fed extruded soybeans had lower concentrations of C18:2 and C18:3 than did cows fed micronized or roasted soybeans; cows fed ground raw soybeans had intermediate concentrations of C18:2 and C18:3.

Twenty-four multiparous Holstein cows, 4 of which were ruminally fistulated, were assigned to one of four diets containing full-fat soybeans, either raw or extruded at 120, 130, or 140 degrees C. Our hypothesis was that the extrusion of full-fat soybeans, as well as the extrusion temperature, would affect the bypass of fatty acids in the rumen and, thus, would modify the fatty acid profile of milk fat. Total mixed diets containing 23.7% soybeans (percentage of DM) were fed for 8 wk. Milk yield was lower, and the proportion of milk CP was higher, for cows fed raw soybeans than for cows fed extruded soybeans. Compared with raw soybeans, extruded soybeans increased the concentration of delta-11-trans-C18:1 from 2.72 to 11.41% in milk fat but had no effect on yield or percentage of milk fat. Polyunsaturated fatty acids of raw soybeans disappeared more rapidly than did those of extruded soybeans from bags incubated in the rumen of fistulated cows. However, more delta-11-trans-C18:1 and C18:0 appeared in bags containing extruded soybeans than in bags containing raw soybeans. Extrusion of full-fat soybeans influenced the metabolism of fatty acids in the rumen and the fatty acid profile of milk fat, but the temperature of extrusion had only minor effects on these parameters.

Twenty-four multiparous Holstein cows averaging 104 d of lactation were used in a trial with a split-plot design to evaluate the nutritive value of two silages, timothy grass or alfalfa, both treated with formic acid and stored in plastic bag silos. Silages were offered for ad libitum intake either alone or with 17 or 34% (dry matter basis) dry-rolled barley. Both silages contained similar amounts of acid detergent fiber (ADF) (27.5 and 26.7% for timothy grass and alfalfa, respectively). After 110 d of storage, alfalfa silage contained higher amounts of organic acids and NH3 N but had lower soluble N. Total dry matter intake (DMI) and silage DMI were similar between cows fed both silages. Increased barley proportion decreased silage DMI (19.2 to 14.2 kg/d). Apparent total tract digestibility of dry matter was unaffected by treatment. The digestibility of neutral detergent fiber and ADF was higher for the timothy grass silage than for alfalfa silage and was unaffected by the barley percentage added to either silage. Milk yield was lower (23.9 to 22.6 kg/d) for cows fed the highest proportion of barley. The 4% fat-corrected milk yield was unaffected by treatment. Percentages of fat, protein, and total solids in milk were higher for cows fed diets with the higher barley content. Milk fat and protein yields were similar among treatments. Urea in blood was lower for cows fed timothy grass silage than for cows fed alfalfa silage (4.68 vs. 6.23 mg/100 ml). These results suggest that timothy grass silage and alfalfa silage, when stored at a similar ADF content, have comparable nutritive value for midlactation cows.

The effects of dietary supplements of folic acid on growth performances and haematological and hepatic variables of white veal calves were studied in 90 young dairy calves. From the age of approximately 2 weeks, they received twice daily 0, 4 or 16 mg of supplementary folic acid added to the milk replacer. They were fed exclusively milk replacer for 105 days. Supplements of folic acid increased serum (P less-than-or-equal-to 0.05) and red blood cell (P less-than-or-equal-to 0.05) folate concentrations, and slowed the decrease with age of haemoglobin and packed cell volume (P less-than-or-equal-to 0.05). The addition of 4 or 16 mg of folic acid twice daily to the milk replacer increased hepatic folates by a factor of 39.5% and 57.4%, respectively, as compared to controls (P less-than-or-equal-to 0.05). Folic acid improved growth (P less-than-or-equal-to 0.05), but had no effect on feed intake (P > 0.05). Time required to reach 180 kg decreased linearly as supplements of folic acid increased (P less-than-or-equal-to 0.05). Calves receiving 0, 4 or 16 mg of folic acid twice daily reached 180 kg in 95.3 +/- 2.7, 89.9 +/- 1.1, or 88.7 +/- 1.4 days, respectively. It was concluded that dietary supplements of folic acid improved haematological variables and shortened the rearing period of white veal calves without increasing their feed intake.

This experiment aimed to evaluate the folic acid requirements of gestating and lactating gilts. Three groups of gilts received, during gestation, a diet supplemented with either 0, 5 or 15 mg/kg of folic acid. At parturition, each of these groups was subdivided into three subgroups. In each subgroup, the lactation diet was supplemented with 0, 5 or 15 mg/kg of folic acid. The level of folic acid during gestation had no effect on the body weight gain of gilts during gestation but increased linearly (P less-than-or-equal-to 0.02) the body weight loss during lactation. During gestation and lactation, addition of folic acid increased (P less-than-or-equal-to 0.05) the concentrations of serum folates. Litter size at parturition and at weaning was not affected by the treatments, although it was numerically higher in sows receiving 15 mg/kg of folic acid during gestation. Milk yield and milk fat, protein and lactose were not influenced by treatments. Concentration of milk folates measured at 1 and 3 weeks of lactation increased (P less-than-or-equal-to 0.001) with the level of folic acid in the lactation diet; an effect of the gestation treatments was observed at 1 week (P less-than-or-equal-to 0.001) but had disappeared by the third week of lactation. In piglets, the concentration of serum folates tended to follow the changes observed on milk folates. Growth of piglets and total litter weight from birth to 8 weeks of age increased linearly (P less-than-or-equal-to 0.05) with the level of folic acid in the gestation diet. Therefore, a dietary supplement of 15 mg/kg of folic acid was necessary to avoid the drop in concentrations of serum folates of sows in gestation and seemed to influence some traits of the reproductive performance.

Two experiments were conducted with 24- to 72-h-old male piglets. In exp. 1, 24 piglets were assigned to three dietary treatments. In the control diet, 100% of the dietary protein originated from low-heat skimmed milk powder. In the other diets, either 25 or 50% of the milk proteins were replaced by oat protein concentrate. In exp. 2, eight piglets were assigned to each of two diets where 100% of the dietary protein originated from skimmed milk powder and 50% of the milk proteins were replaced by oat protein concentrate. In exp. 1, dry matter intake was not affected by treatments while body weight gain declined and feed to gain ratio increased significantly (P < 0.05) when oat protein concentrate replaced 50% of the milk proteins. Similar observations were made in exp. 2 regarding dry matter intake, body weight gain and feed gain ratio although digestibility of dry matter and nitrogen was the same (P > 0.05) for both the oat and milk protein treatments. Oat protein concentrate can thus replace up to 50% of milk proteins without apparent detrimental effect on dry matter intake and N digestibility; however, growth rate will be reduced. Key words: Piglets, artificial rearing, milk replacer, skimmed milk powder, oat protein concentrate, digestibility

Fourteen Holstein calves, two to four days of age, were randomly divided into two groups to determine the effect of abomasal curd suppression on selected blood profiles. Calves received a milk replacer in which casein coagulation either was normal (CM), or was prevented by the precipitation of Ca++ with an oxalic acid - sodium hydroxide buffer (NCM). Jugular blood samples were taken before the morning feeding (O h), as well as at 1, 2, 4 and 6 h postfeeding. Fasting (O h) plasma free essential amino acid (EAA) concentration tended to be higher for the CM treatment than for the NCM treatment, while the contrary was observed for postprandial values up to 6 h post-feeding. Plasma EAA concentration increased significantly during the first hour post-feeding for the NCM treatment, whereas values remained fairly constant for the CM treatment. Plasma triglyceride concentration was significantly higher for the CM treatment at 0, 4 and 6 h post-feeding, while it was higher for the NCM treatment at 1 h post-feeding. The fasting plasma glucose concentration was similar for both treatments. Plasma glucose was significantly higher for the CM treatment at 2 h post-feeding, but the contrary was observed thereafter. For the CM treatment, the plasma glucose profile almost mirrored the triglyceride profile. It was concluded that profiles of plasma free EAA and triglycerides may be reliable indicators of in vivo curd-forming ability of a given milk replacer, and that abomasal curd suppression may have a detrimental effect on amino acid and caloric homeostasis.

Two trials were conducted to determine the effect of coagulation suppression of milk and milk replacers on apparent digestibility coefficients and body mass-gain of calves. In Experiment 1, two groups of five Holstein bull calves, two to four days of age, were given a milk replacer in which casein coagulation either was normal (CM), or was prevented by the precipitation of Ca++ with an oxalic acid - sodium hydroxide buffer (NCM). Apparent digestibility of dry matter, organic matter, crude protein and fat was 87 and 91%, 88 and 92%, 75 and 84% and 83 and 87% for the NCM and CM treatments, respectively. Treatment means did not differ statistically, although there was a tendency towards lower crude protein digestibility for the NCM treatment. Owing to Ca++ precipitation in the one treatment, apparent ash and calcium digestibility (availability) coefficients were significantly lower for the NCM treatment than for the CM treatment, viz. 65 vs. 83% and 29 vs. 78%, respectively. In Experiment 2 (growth trial), four groups of seven Friesian bull calves, two to four days of age, were used. Whole milk (WM) and a commercial coagulable milk replacer (CM), were used either directly, or after treatment with oxalic acid (NWM and NCM). Body mass-gain (kg) and efficiency of feed conversion (kg dry matter intake/kg gain) over the 28-day experimental period were respectively 7,3 and 1,8 (WM); 7,3 and 1,8 (NWM); 4,3 and 3,9 (CM) and 4,9 and 2,9 (NCM). Both whole milk treatments were superior to milk replacer treatments, but prevention of coagulation per se had no significant effect on calf performance and on the occurrence of diarrhoea.

The purpose of this trial was to determine whether an addition of folic acid to a commercial diet would affect serum Zn, Fe and Cu status in sows between weaning and 30 d of gestation. At weaning, 162 sows were assigned randomly to six groups and housed in individual cages fitted on a slatted floor. There were six treatments according to a 2 X 3 factorial arrangement: two levels of supplementary folic acid (0 and 5 mg/kg of diet) and three treatments to stimulate ovulation (none, flushing and pregnant mare serum gonadotropin [PMSG] i.m. injection). Control groups were fed a commercial-type diet, and folic acid-treated groups were fed the same diet supplemented with 5 mg/kg of pteroylglutamic acid. All sows were mated twice within 7 d after weaning. Of the 162 animals originally selected, 123 sows were pregnant and used in this trial. Serum folates, Zn, Cu and Fe were measured at weaning, mating and 30 d of gestation. Serum Cu, Zn and folates increased between weaning and mating, and then decreased to 30 d of gestation. Supplementing the commercial diet with folic acid elevated serum folates between weaning and d 30 of gestation (P less than .001). Folic acid supplementation also was associated with a higher level of serum Zn at 30 d of gestation. Supplemental folic acid had no effect on the pattern of serum Cu and Fe throughout the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Eight Holstein male calves, each fitted with an ileal reentrant cannula at 7 to 10 d of age, were fed a milk replacer based on low heat skim milk powder with or without an oxalate-NaOH buffer known to prevent curd formation in the abomasum. The calves were used to study the effects of milk clotting on digesta flow at the ileum and apparent digestibility measured by fecal and ileal collection. Patterns of ileal flow of total digesta, DM, N, and fat were similar for the clotting and the nonclotting milk replacers. The apparent digestibility of DM and N was higher when measured by fecal than ileal collection for both milk replacers. Digestibility of DM was higher for the clotting than for the nonclotting milk replacer when measured by ileal collection. Clotting did not affect N digestibility measured by either fecal or ileal collection. The concentration of amino acids differed generally in the ileal digesta compared with concentration in feces. In the ileal digesta, some amino acids showed lower concentrations in the clotting milk replacer fed calves compared with those fed the nonclotting milk replacer. The coefficients of digestibility of each amino acid were similar when measured by either fecal or ileal collection. Clotting had no effect on amino acid digestibility measured by both fecal and ileal collection. The data suggest that fecal collection might indicate higher digestibility as compared with ileal collection and that the absence of milk replacer clotting does not affect ileal flow and digestibility of milk replacer N and fat.

At weaning, 162 sows were assigned randomly to six treatments (27 in each treatment) according to a 2 X 3 factorial arrangement: two levels of supplementary folic acid (0 and 5 mg/kg of diet) and three treatments to stimulate ovulation (none, flushing and pregnant mare serum gonadotropin [PMSG] injection). All sows were mated twice within 7 d after weaning. Of the 162 animals originally selected, 123 sows were pregnant and used in this trial. The flushing treatment consisted of allowing sows ad libitum access to feed from the day after weaning through the 1st day of behavioral estrus, whereas control animals received 2.4 kg of feed daily. The hormonal treatment consisted of one i.m. injection of 1,250 IU of PMSG the day after weaning. The commercial-type diet used as the control was computed to contain .6 mg folates per kilogram. Folic acid supplementation elevated (P less than .001) serum folates between weaning and 30 d of gestation. Fetuses of sows fed the diet supplemented with folic acid had a higher (P less than .05) total protein concentration than fetuses of control sows, whereas RNA and DNA concentrations and protein:DNA ratio were not affected. The PMSG treatment elevated (P less than .05) ovulation rate, whereas the flushing or folic acid treatments had no effect on this trait. The addition of 5 mg/kg folic acid to the commercial-type diet improved (P less than .05) the survival rate of fetuses during early gestation and tended (P = .096) to increase the number of fetuses presumably living at 30 d of gestation when this treatment was associated with high ovulation rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Forty-eight 5-wk-old piglets were grouped into six blocks of eight pigs each. Each block comprised two pens of four pigs, two castrates and two females; one pen had a solid floor (free access to feces) while the other had a slatted floor (limited access to feces). Pigs were fed ad libitum a diet computed to meet NRC requirements for 18 wk. Every 14 d, each animal was weighed and a blood sample was taken for the determination of folates, vitamin B12, biotin, hemoglobin (Hb) and hematocrit (Ht) levels. There was no effect (P > 0.05) of floor type on serum folates or vitamin B12, nor on plasma biotin which averaged, respectively, 72.2 ± 2.9 ng mL−1, 246.0 ± 21.3 pg mL−1 and 1.34 ± 0.1 ng mL−1 at the end of the experiment. Biotin concentration was about 16-fold greater in the feces than in the diet, which was indicative of active bacterial synthesis of B-complex vitamins in the gut. Hb and Ht were about 4% higher (P < 0.05) in pigs on slatted floors than in those on solid floors. From 5 to 11 wk, pigs raised on slatted floors grew faster (P < 0.05) than those raised on solid floors, but growth rate was similar (P > 0.05) on both floor types from 11 to 23 wk. The results suggest that whatever the age of growing pigs, coprophagy is not an important way by which these animals meet their requirements in B-complex vitamins. Key words: Pigs, floor type, coprophagy, folates, vitamin B12, biotin

Two experiments involving 3- to 5-d-old dairy calves were carried out. In Experiment 1, lime-treated corn flour (Nixtamal) supplied 50 to 100% of carbohydrates in a milk substitute based on sodium caseinate, lard, and cerelose. In Experiment 2, partially hydrolyzed fish protein concentrate replaced 50% of 67% of proteins in milk substitutes based on skim milk powder, lard, and 35% Nixtamal. Increasing the proportion of carbohydrates supplied by Nixtamal was associated with a linear decrease of postprandial serum glucose and insulin. Postprandial fluctuations in blood glucose were less in calves fed Nixtamal than in controls. Nixtamal probably was trapped within the casein clot in the abomasum, leading to delayed rate of passage of Nixtamal carbohydrates into the intestine. Replacing skim milk protein with hydrolyzed fish protein in diets containing Nixtamal had no effect on blood glucose or insulin but elevated free essential amino acids, which promoted glucagon secretion. More uniform concentrations of blood essential amino acids and glucose were related to lower blood urea at 54 d in calves fed diets based on hydrolyzed fish protein and Nixtamal, than that of control calves. It is suggested that more uniform postprandial blood glucose concentrations might reduce amino acid degradation for energy purposes and stimulate protein synthesis. Young dairy calves may adapt to milk substitutes based on Nixtamal and hydrolyzed fish protein despite changes in the concentration patterns of several blood components.

Four Holstein male calves, each fitted with a simple duodenal cannula and a reentrant ileal cannula at 7 to 10 d of age, were fed a nonclotting milk replacer based on skim milk powder. The calves were divided into two groups and were infused with either saline (control) or a saline-glucose solution (treatment) according to a switchover design. Glucose infusion improved N retention and decreased plasma concentration of amino acids and urea. Insulin and triglycerides in plasma were not different between the two groups. Ileal flow and digestibility of dietary components were not affected by glucose infusion. The data suggest that additional energy as glucose is needed to optimize N utilization in preruminant calves fed a nonclotting milk replacer.