Caprine immunoglobulin G,beta-lactoglobulin,alpha-lactalbumin and serum albumin in colostrum and milk during the early post partum period

Colostrum and milk samples from 20 goats were analysed for concentrations of immunoglobulin G (IgG), beta-lactoglobulin (beta-lg), alpha-lactalbumin (alpha-la) and serum albumin (CSA) throughout the first 14 milkings post partum (7 d of lactation) using single radial immunodiffusion assay. Concentrations (mg/ml, means +/- SD) at first milking were IgG 47.9 +/- 25.5, beta-lg 30.7 +/- 10.4, alpha-la 2.77 +/- 0.82 and CSA 2.97 +/- 2.46 mg/ml. Large variations were recorded for IgG concentrations (19.9-94.5 mg/ml) and beta-lg (9.3-49.8 mg/ml). Concentrations of IgG, beta-lg and CSA dropped abruptly in the subsequent milkings and alpha-la concentration decreased slowly. Mean IgG concentration was < 2 mg/ml after 7 milkings and < 1 mg/ml after 11 milkings. However, IgG concentration does not differ significantly, at the 1% level, from milkings 7-14. The contribution of beta-lg to the increase in whey proteins in early milks was greater than that of IgG from milkings 5 to 14. The results were tabulated to make it possible to calculate the excess of whey proteins that would be obtained if early milks were illegally added to milk supply.     

Camel (Camelus dromedarius) immunoglobulin G, alpha-lactalbumin, serum albumin and lactoferrin in colostrum and milk during the early post partum period

Colostrum and milk samples from twelve Tunisian camels were analysed for concentration of immunoglobulin G (IgG), alpha-lactalbumin (alpha-la), serum albumin (CSA) and lactoferrin throughout the first 14 milkings post partum (7 days of lactation) using single radial immunodiffusion assay. Concentrations (mg/ml, means+/-SD) at first milking were IgG, 100.7+/-60.4; alpha-la, 2.2+/-0.7; CSA, 8.5+/-3.6 and lactoferrin, 1.2+/-0.3. Large variations were recorded for IgG and CSA concentrations (11.8-211.1 mg/ml and 2.9-13.8 mg/ml respectively) Concentrations of IgG and CSA dropped abruptly in the subsequent milkings while alpha-la concentration increased until milking 5 and then decreased slowly. Lactoferrin dropped only from milking 7. Mean IgG concentrations were 3.6 and 2.5 mg/ml at milking 9 and 13 respectively. However, IgG concentration did not differ significantly, at the 1% level, from milkings 11 to 14. The contribution of CSA to the increase in whey proteins in early milks was greater than that described in the bovine and caprine species.     

Kinetics of heat-induced whey protein denaturation and aggregation in skim milks with adjusted whey protein concentration

Microfiltration and ultrafiltration were used to manufacture skim milks with an increased or reduced concentration of whey proteins, while keeping the casein and milk salts concentrations constant. The skim milks were heated on a pilot-scale UHT plant at 80, 90 and 120 degrees C. The heat-induced denaturation and aggregation of beta-lactoglobulin (beta-lg), alpha-lactalbumin (alpha-la) and bovine serum albumin (BSA) were quantified by polyacrylamide gel electrophoresis. Apparent rate constants and reaction orders were calculated for beta-lg, alpha-la and BSA denaturation. Rates of beta-lg, alpha-la and BSA denaturation increased with increasing whey protein concentration. The rate of alpha-la and BSA denaturation was affected to a greater extent than beta-lg by the change in whey protein concentration. After heating at 120 degrees C for 160 s, the concentration of beta-lg and alpha-la associated with the casein micelles increased as the initial concentration of whey proteins increased.     

Factors associated with colostral specific gravity in dairy cows

The objectives of this study were to identify factors associated with colostral specific gravity in dairy cows, as measured by a commercially available hydrometer (Colostrometer). Colostral specific gravity was measured in 1085 first-milking colostrum samples from 608 dairy cows of four breeds on a single farm during a 5-yr period. Effects of breed, lactation number, and month and year of calving on colostral specific gravity were determined, as were correlations between colostral specific gravity, nonlactating period length, and 305-d yields of milk, protein, and fat. For 75 multiparous Holstein cows, relationships between colostral specific gravity, colostral IgG1, protein, and fat concentrations, and season of calving were determined. Colostral specific gravity values were lower for Brown Swiss and Ayrshire cows than for Jersey and Holstein cows, and lower for cows entering first or second lactation than third or later lactations. Month of calving markedly affected colostral specific gravity values, with highest values occurring in autumn and lowest values in summer. In multiparous Holstein cows, colostral specific gravity was more strongly correlated with colostral protein concentration (r = 0.76) than IgG1 concentration (r = 0.53), and colostral protein concentration varied seasonally (higher in autumn than summer). Our results demonstrate that colostral specific gravity more closely reflects colostral protein concentration than IgG1 concentration and is markedly influenced by month of calving. These results highlight potential limitations of using colostral specific gravity as an indicator of IgG1 concentration.     

Prostaglandin in milk, days open, and estrus detection in dairy cows treated with prostaglandin F2 alpha

Prostaglandin F2 alpha was used to induce estrus in postpartum dairy cows to decrease calving interval and time spent on heat checks. The amount of prostaglandin residue in milk after treatment also was investigated. Twenty-two control cows, checked for heat twice daily, were bred at estrus after 55 days postpartum. Sixty-three cows checked on days 55 to 60 were either bred if in estrus or treated with 30 mg of prostaglandin F2 alpha injected intramuscularly on day 60 and bred at induced estrus or at 75 h posttreatment. Twelve cows were in heat between days 55 and 60 and were bred. Twenty-nine of 51 treated cows were seen in estrus; all of these were bred and 51.7% conceived at this time. Treated cows had fewer days to first service than did controls, but days open were not different, 105.7 versus 101.8. Fertility was similar. Controls required more heat checks than did treated cows (39 to 8.2). Milk from 17 cows at two milkings before and ten milkings after treatment had similar concentrations of prostaglandin (698 +/- 27 pg/ml) except for the first posttreatment milking when prostaglandin concentration almost doubled (1.293 +/- 143 pg/ml).     

Management and production factors influencing immunoglobulin G1 concentration in colostrum from Holstein cows

Immunoglobulin G1 concentration was measured in 919 first milking colostrums from Holstein cows during a 4-yr period on a commercial dairy farm. Sources of variation analyzed for effect on colostral IgG1 concentration were season of calving, lactation number, dry period length, intercalving interval, complete lactation milk and fat production, weight of first milking colostrum, and time from calving to first milking. Weight of first milking colostrum was the variable most highly correlated (negatively) with colostral IgG1 concentration (r = -.29). Weight of first milking colostrum and lactation number of the cow were the most significant discriminators between colostrum of low and high IgG1 concentration. The implications of these results for colostrum feeding management are discussed.     

Milking of cows in late pregnancy: milk production during this period and during the succeeding lactation.

Fifteen lactating cows were milked throughout pregnancy, and the effects on milk performance were studied during this period and during the succeeding lactation, relative to 11 conventionally managed cows (2 months dry before calving) as controls. During the last 2 months of pregnancy, only nine cows did not dry off spontaneously. Protein and fat concentrations in milk increased rapidly, but the concentration of lactose, corrected for milk yield, did not change. The ratios of individual caseins to total protein decreased with the quantity of milk produced, but only for yields below approximately 6 kg/d. The relative proportion of kappa-casein tended to decrease in the last milkings. During the succeeding lactation (first 15 weeks after calving and first 6 weeks of grazing) continuously milked cows yielded 4 kg milk/d less than the cows of the other group. The protein content of their milk was higher (2-3 g/kg depending on the period) than that of the control group, and the lactose content tended (P less than 0.10) to be lower. Changes in the relative proportions of nitrogenous fractions with time were not different in the two groups. Differences between the two groups in the concentration of protein in milk, and in the concentration of glucose and non-esterified fatty acids in the plasma, suggest a better energy balance for the continuously milked cows during the succeeding lactation.     

High pressure-induced denaturation of alpha-lactalbumin and beta-lactoglobulin in bovine milk and whey: a possible mechanism

In this study, high pressure (HP)-induced denaturation of alpha-lactalbumin (alpha-la) and beta-lactoglobulin (beta-lg) in dairy systems was examined. In both milk and whey, beta-lg was less baroresistant than alpha-la; both proteins were considerably more resistant to HP-induced denaturation in whey than in milk. HP-induced denaturation of alpha-la and beta-lg increased with increasing proportion of milk in mixtures of milk and whey. Addition of a sulphydryl-oxidising agent, KlO3, to milk or whey increased HP-induced denaturation of beta-lg, but reduced the denaturation of alpha-la. Denaturation of both alpha-la and beta-lg was prevented by adding a sulphydryl-blocking agent, N-ethylmaleimide, to milk or whey prior to HP treatment, highlighting the crucial role of sulphydryl-disulphide interchange reactions in HP-induced denaturation of alpha-la and beta-lg. Removal of colloidal calcium phosphate from milk also reduced HP-induced denaturation of alpha-la and beta-lg significantly. The higher level of HP-induced denaturation of alpha-la and beta-lg in milk than in whey may be the result of the abscence of the casein micelles and colloidal calcium phosphate from whey, which facilitate HP-induced denaturation of alpha-la and beta-lg in milk.     

Comparison of total and free cortisol in bovine serum and milk or colostrum

Total (free plus protein-bound) and free cortisol concentrations in paired samples of serum and skim milk or colostrum were determined by specific radioimmunoassay after extraction or ultrafiltration. For 11 cows in established lactation mean total cortisol concentrations +/- SE in serum and milk were 4.5 +/- .7 ng/ml and .35 +/- .06 ng/ml, respectively. Concentrations of free cortisol in serum and milk were about .3 ng/ml, which is at the lower limit of the present assay. Following 200 IU Synacthen injection to 5 cows, total cortisol in serum and milk rose to 67 +/- 6.0 ng/ml and 11.4 +/- 1.5 ng/ml by 8 h postinjection, while free concentrations increased to 4.3 +/- .7 ng/ml and 6.5 +/- .8 ng/ml in serum and milk, respectively. Eight additional cows were sampled at 1 to 2 d after parturition, and total cortisol in serum and colostrum was 16.6 +/- 1.6 ng/ml and 4.4 +/- 1.3 ng/ml, and free cortisol was 2.4 +/- .4 ng/ml and 1.8 +/- .5 ng/ml, respectively. Free cortisol concentrations in colostrum or in milk from cows in established lactation, before or after adrenal stimulation, are directly related to free cortisol concentrations in the blood, while the bound cortisol in milk is more related to these two stages of lactation rather than the bound hormone in the blood. Measurement of free cortisol in milk should allow the monitoring of changes in plasma free cortisol in studies of stress in dairy cows.     

Immunoglobulin isotype concentrations in milk as affected by stage of lactation and parity

Quarter milk samples were collected during lactation and analyzed for immunoglobulins from 32 first and 16 third lactation Holstein cows that were equally distributed progeny of sires selected for yield or merit. Variance component estimates indicated large variation for cow, quarter within cow, and stage of lactation. All immunoglobulin isotype concentrations were lowest at wk 21. Significant differences between first and third lactation cows were observed for milk immunoglobulin A (.012 and .018 mg/ml) and immunoglobulin M (.074 and .101 mg/ml). Quarters with cell counts above 1 X 10(6) cells/ml had higher concentrations of immunoglobulin G1, (.619 vs. .394 mg/ml) immunoglobulin G2 (.103 vs. .063 mg/ml), immunoglobulin A (.028 vs. .014 mg/ml), and immunoglobulin M (.117 vs. .087 mg/ml). There were no significant differences in immunoglobulin isotype concentrations due to genetic group (yield or merit), suggesting that selection for milk production has no significant effect on immunoglobulin concentration in milk. Degree of parity, however, must be considered when comparing immunoglobulin A and immunoglobulin M concentrations in milk.     

Short communication: Mammary gland tight junction permeability after parturition is greater in dairy cows with elevated circulating serotonin concentrations

After parturition, the start of copious milk production in dairy cows requires the closure of tight junctions (TJ) to form the blood–milk barrier and prevent paracellular transfer of blood constituents into milk [e.g., lactate dehydrogenase (LDH) and serum albumin (SA)] and vice versa [e.g., appearance of α-lactalbumin (α-LA) in blood]. Serotonin (5-HT) has been demonstrated to alter tight junction permeability in the mammary gland. The present study investigated individual differences of TJ permeability of mammary epithelium at the beginning of lactation in relation to circulating 5-HT in dairy cows. Blood and milk samples were obtained from 11 multiparous Holstein dairy cows for the first time at 4 h after parturition, at the following 5 milkings, and at the evening milkings on d 5, 8, 10, and 14 of lactation. Retrospectively, cows were split into 2 groups according to their calculated areas under the curve of serum 5-HT during the entire experimental period: a high-serum 5-HT (HSS) group (5 cows) and a low-serum 5-HT (LSS) group (6 cows). The areas under the curve of serum 5-HT concentrations over the 324-h experimental period were 62 ± 2 × 10³ ng/mL in HSS and 25 ± 5 × 10³ ng/mL in LSS. Plasma α-LA concentration was greater in LSS than in HSS cows at the first milking, but no difference between groups was found from the second to sixth milking. Yield of α-LA in milk was lower in HSS than in LSS during the first 6 milkings postpartum, especially in colostrum. Concentrations of α-LA, IgG₁, and IgG₂ in milk did not differ between groups during the entire experiment except for higher IgG observed in LSS than in HSS at the second milking and for higher IgG₂ found in HSS compared with LSS on d 5. In contrast, SA concentrations and LDH activity in milk were lower in LSS compared with HSS cows during the first 6 milkings postpartum, particularly in colostrum. Milk somatic cell count was higher in HSS than in LSS throughout the study. Higher circulating 5-HT concentrations were associated with an increased transfer of the paracellularly transported SA, LDH, and somatic cell count, especially at the first milking, suggesting that 5-HT affects TJ permeability during closure of the blood–milk barrier at the onset of lactation. Furthermore, higher serum 5-HT concentrations were associated with a lower α-LA yield in milk. A consistent relationship with serum 5-HT concentrations was neither observed for the transfer of IgG₂ nor the primarily transcellular transport of IgG₁ during the first milkings after parturition.     

Failure of cortisol injected prior to milking to inhibit milk ejection in dairy cattle

To test the potential for cortisol to inhibit milk ejection directly, 18 Holstein cows were divided equally into control and treatment groups based on milk yields. For treated animals, a single injection of cortisol was made into the saphenous vein 15 min before milkings. Increasing amounts of cortisol (0, 25, 50, and 100 mg) were injected for one morning and one evening milking, with the exception that the treated cows received only one 100 mg injection. Control animals received injections of 0.9% (w/v) NaCl. Cortisol injections had no effect on milk yields. However, a potential inhibitory mechanism might involve a delay, perhaps due to the necessity of synthesizing a regulatory protein. Therefore, to test the potential for increased cortisol over a period of hours to inhibit milk ejection, six of the nine cows in the treatment group were injected with 100 mg of cortisol at 3.25, 2.25, 1.25 and 0.25 h before sequential morning and evening milkings. In blood samples taken 1 min before and after injections, base-line cortisol concentrations averaged 10.2 mg/ml; after injection they were 984.1 ng/ml, and before subsequent injections they were 37.6 ng/ml. Again cortisol injections had no effect on milk yields.     

Hormonal induction of lactation: estrogen and progesterone in milk

Estrogen and progesterone in milk during the first 21 days of induced and postpartum lactation in Holstein cows and heifers were estimated by assay procedures. Lactation was induced with estradiol-17 beta and progesterone treatment for 7 days. Estrogen and progesterone in induced lactations differed from concentrations in postpartum lactations. In early lactation estrogen was higher in postpartum milk (521 +/- 103 pg/ml on day 1) than in induced milk (336 +/- 46 pg/ml on day 1), but after day 7 the reverse was true (192 +/- 33 pg/ml and 233 +/- 32 pg/ml on day 7). Progesterone remained higher in induced lactation through the first 21 days than in postpartum lactation with the exception of day 19. Progesterone in postpartum milk increased from 4 +/- 1 ng/ml on day 1 to 11 +/- 2 ng/ml on day 21. Progesterone in induced milk showed greater fluctuation (11 +/- 3 ng/ml on day 1 and 22 +/- 9 ng/ml on day 3) but gradually decreased to 12 +/- 2 ng/ml on day 21 (11 +/- 2 ng/ml on day 21 of postpartum lactation).     

Season and treatment effects on serum prolactin and milk yield during induced lactation

Nineteen nonpregnant, nonlactating dairy cows were allotted to three treatments to induce lactation during winter, 1976, or spring, 1977. All groups received 17 beta-estradiol (.1 mg/kg) days 1 to 7. Groups 2 and 3 also received progesterone (.25 mg/kg) days 1 to 7. Groups 1 and 2 were given reserpine (5 mg intramuscular) on days 8, 10, 12, and 14. Group 3 received reserpine (5 mg intramuscular) on days 2, 5, 8, 11, and 14. Blood samples were collected for prolactin analysis just prior to and 3 h after reserpine injection. Mean daily temperatures were 11.9 C for spring group and -6.5 C for winter group. Comparisons of spring with winter for basal prolactin concentrations, reserpine-stimulated prolactin concentrations, and 100-day milk yields were 44 with 10 ng/ml, 482 with 199 ng/ml, and 1991 with 862 kg. Differences in prolactin concentrations and milk yields among hormone and reserpine treatments could not be detected, but cows on treatment 3 in the spring gave the largest yield of milk. Prolactin concentrations were correlated with milk yields among cows and among cows within seasons. Seasonal differences demonstrate the critical role of prolactin in the treatment to induce lactation.     

Milk trypsin-inhibitor capacity as an indicator of bovine mastitis--a novel principle which can be automated

As mastitis is associated with leakage of small molecular weight plasma proteins, such as alpha 1-antitrypsin, into milk, this antitrypsin can be used as an indicator of mastitis. A colorimetric procedure was developed for large scale monitoring of milk antitrypsin activity, using microtitration plates and the Multiskan system. The effect of stage of lactation and age of the cow on the antitrypsin concentration and its interrelationship with other mastitis indicators (bovine serum albumin (BSA), somatic cell count) was analysed by computer programs on 1029 cows. Milk antitrypsin activity was high after parturition owing to colostral inhibitors. After the first month of lactation the assay measures only blood-derived antitrypsin and is a good indicator for detecting an increased permeability between blood and milk due to mastitis. Increasing lactation number only slightly affected the antitrypsin and BSA concentrations whereas somatic cell content was markedly affected.     

Effect of dietary energy and previous bovine somatotropin on milk yield, mastitis, and reproduction in dairy cows.

Thirty multiparous lactating Holstein cows were blocked according to time of calving and assigned to a 2 x 3 factorial arrangement of treatments in a randomized complete block design to evaluate the effects of two dietary energy concentrations either without or with bST (20.6 mg/d per cow) administered to cows that had not or had received bST during the preceding lactation. Subcutaneous injection of bST began 28 to 35 d postpartum and continued for 39 wk. The dietary energy concentration x bST interaction was not significant for any response variable. Compared with DMI of control cows, DMI was higher for cows receiving bST, being 1.6 and 2.4 kg/d higher for cows receiving bST for one and two lactations, respectively. Milk, fat, and protein yields were higher for cows receiving bST than for controls. Those receiving bST for a second lactation also produced more milk than controls until wk 20; thereafter, milk yields were similar to those of controls. Somatotropin administration had no adverse effect on udder health. Cows receiving bST tended to ovulate less regularly than controls, which may be attributed to their higher milk yield. However, BW gains during lactation were similar for all treatments, indicating that bST-treated cows built energy reserves for the subsequent lactation. Although energy concentrations of the diets had no significant impact on yield, the higher energy diet tended to depress milk fat concentration. Administration of bST to dairy cows for a second, consecutive lactation yielded responses similar for the first 20 wk of the study to those receiving bST for the first time. However, after wk 20, milk yield was less than that by cows receiving bST for the first lactation but similar to that of control cows.     

Short communication: Circulating serotonin is related to the metabolic status and lactational performance at the onset of lactation in dairy cows

Serotonin (5-hydroxytryptamine, 5-HT) affects many physiological functions because it is involved in glucose and lipid metabolism, calcium homeostasis, and regulation of lactation in dairy cows. This study aimed to examine physiological differences in serum 5-HT concentrations (high vs. low) and their association with metabolic status and milk production at the onset of lactation. Twelve multiparous Holstein dairy cows were milked within 4 h of calving, and blood and milk samples were collected at the first 6 subsequent milkings after parturition and at the evening milkings on d 5, 8, 10, and 14. Cows were retrospectively divided into 2 groups (6 cows/group): low serum 5-HT (LSS) and high serum 5-HT (HSS) according to their calculated areas under the curve (AUC) for serum 5-HT for the entire experimental period (cut-off: 46,000 ng/mL × 324 h). Concentrations of 5-HT, free fatty acids (FFA), β-hydroxybutyrate (BHB), glucose, calcium, and IGF-1 were measured in blood. Milk was analyzed for fat, protein, lactose, and 5-HT concentrations. Milk yield was recorded at each milking and energy-corrected milk yield was calculated. Serum 5-HT concentrations were higher in HSS than in LSS [AUC (ng/mL × 324 h): 57,830 ± 4,810 vs. 25,005 ± 5,930]. The amount of energy-corrected milk was lower in HSS than in LSS. The HSS group produced less colostrum and had decreased milk yield, specifically during the first 6 milkings. Concentrations of FFA, BHB, and glucose in plasma did not differ between groups. Concentrations of IGF-1 in serum were elevated in HSS compared with LSS throughout the experiment. Total circulating calcium concentrations in serum tended to be higher in HSS than in LSS. Milk fat and protein yields were decreased in HSS compared with LSS. Milk 5-HT decreased overall during the experimental period, with LSS maintaining higher 5-HT concentrations than HSS until d 14 of lactation. In conclusion, cows with high serum 5-HT concentrations showed a reduced metabolic load at the onset of lactation, concomitantly lower milk yield, and a reduced energy output via milk.     

Effect of ACTH and oxytocin treatment on lactoferrin and citrate in cows' milk

Six dairy cows were treated before milkings with either oxytocin (Pitocin, 20 i.u.) or ACTH (Synacthen, 150 i.u.), principally to determine their effect on the ratio of citrate: lactoferrin concentrations in the milk. With ACTH treatment, after 3 d milk yield and citrate concentration decreased significantly, lactoferrin and bovine serum albumin (BSA) concentrations increased significantly. Somatic cell counts (SCC) increased temporarily in the milk of three of the cows which previously had greater than 100 000 cells/ml. Lactoferrin yield remained fairly constant but citrate yield was significantly reduced. The citrate: lactoferrin molar ratio decreased from 1373 to 606. With oxytocin treatment, after 4 d milk yield first increased and then significantly decreased, citrate concentration decreased significantly while there were no significant changes in lactoferrin or BSA concentration or in the yield of any other milk constituents. The citrate: lactoferrin molar ratio decreased from 1621 to 1301. There were no significant changes in SCC either during treatment or 4 d after treatment but there was a significant rise at 16 d after treatment. It was concluded that in lactating cows both hormones affected citrate and lactoferrin concentrations in the direction that would improve the antibacterial properties of milk, but that this was accompanied by adverse effects on milk secretion. The extent of the change was not sufficient to be likely to produce inhibition of coliform bacteria.     

Goats' milk of defective alpha(s1)-casein genotype decreases intestinal and systemic sensitization to beta-lactoglobulin in guinea pigs

Contradictory results have been reported on the use of goats' milk in cows' milk allergy. In this study the hypothesis was tested, using a guinea pig model of cows' milk allergy, that these discrepancies could be due to the high genetic polymorphism of goats' milk proteins. Forty guinea pigs were fed over a 20 d period with pelleted diets containing one of the following: soyabean proteins (group S), cows' milk proteins (group CM), goats' milk proteins with high (group GM1) or low (group GM2) alpha(s1)-casein content. Parenteral sensitization to GM1 and GM2 proteins as also assessed. The sensitization was measured (1) by systemic IgG1 antibodies directed against bovine or caprine beta-lactoglobulin (beta-lg), alpha-lactalbumin (alpha-la) and whole caseins, and (2) by intestinal anaphylaxis measured in vitro in Ussing chambers, by the rise in short-circuit current (delta Isc) in response to milk proteins. Guinea pigs fed on CM and GM1 developed high titres (> 1500) of anti-beta-lg IgG1, with an important cross reactivity between goat and cow beta-lg. However, in guinea pigs fed on GM2, anti-goat beta-lg IgG1 antibodies were significantly decreased compared with GM1 guinea pigs (mean IgG1 titres were 546 and 2046 respectively), and the intestinal anaphylaxis was significantly decreased (3.5+/-4.5 microA/cm2) compared with that observed in GM1 guinea pigs (8.3+/-7.6 microA/cm2). Animals receiving GM1 or GM2 proteins via the parenteral route developed a marked sensitization. These results suggest that the discrepancies observed in the use of goats milk in cows' milk allergy could be due, at least in part, to the high genetic polymorphism of goats' milk proteins.