- Email: [email protected]
Effect of Nickel Supplementation on Production and Composition of Milk1
Effect of Nickel Supplementation on Production and Composition of Milk GLEN D. O'DELL, '~ W. J. MILLER, 3 W. A. KING, 2 J. C. ELLERS, 2 a~nd H. JURECEK4
Department of Dairy Science, Clemson University Clemson, South Carolina 2963] and Dairy Science Department, University of Georgia Athens 30601 Abstract
or sulfate for chicks (13), 1,100 ppm as the acetate for mice (14), but rats tolerated u 1) to 1,000 ppm as the carbonate or the metal without apparent toxicity (9,10). Generally plants contain less nickel (4,11), usually 0 to 5 ppm but often many times more (4). The normal nickel content in nfilk has not been established but conflicting reports have been published (2). Archibald (1) fed 145mg of elemental nickel daily as niekelous chloride to lactating dairy cows and failed to detect an inc.rease of nickel in milk. The objectives of this study were to ascertain the effect on animal performance and on nickel, fat, protein, and solids-not-fat of milk when lactating cows were fed nickel in amounts lower than those at which toxicity symptoms have been observed with monogastric animals (13,14) but greatly exceeding amounts used in a lactation experiment (1).
Three concentrations of nickel carbonate were fed to 3 groups of 5 lactating dairy cows each. Nickel carbonate was mixed in the concentrate ration at 0, 50 and 250 ppm of elemental nickel and concentrate fed at a ratio of lkg per 3kg of milk produced. Average daily consumption of supplemental nickel per cow was 0, 365 and 1,835mg, respectively. No significant effect on milk production, lnilk composition, animal health or feed consumption was observed. Within the detectable limits of the analytical procedure, feeding nickel did not increase nickel in milk and never exceeded that in plant processed milk. None of the milk samples from cows fed 250 ppm nickel contained as much as 0.1 ppm nickel, which was the lower reliability limit of the procedure. Less than 0.12% of the supplemental nickel appeared in the milk.
Experimental Procedures
Introduction
Knowledge relating to milk content of substances which are toxic or potentially toxic is highly desirable. Also a nmeh better understanding of the principles which regulate the transfer of many trace substances from feed into milk is needed. Nickel is toxic at 40 to 60 ppm for plants (4,5), 700 ppm as the acetate :Received for publication March 24, 1970. 1 Technical contribution no. 850, South Carolina Agricultural Experiment Station. Published by permission of the Director. University of Georgia, College of Agricultural Experiment Stations, Journal paper no. 753, College Station, Athens. 2 Department of Dairy Science, Clemson University. 3 Dairy Science Department, The University of Georgia. 4 Agricultural Chemical Services, Clemson University.
Fifteen multiparous, lactating dairy cows with daily production between 16.5 and 30.0kg were approximately equalized into groups of 3 on age, weight, milk production and stage of lactation. These were randomly allotted to each of 3 treatments. Niekelous carbonate (NiC03) was added to the concentrate to provide 0, 50, and 250 ppm of nickel on an as-fed basis. Nickel carbonate is relatively insoluble in water but was determined to be readily soluble in rumen fluid. One kilogram of concentrate was fed for each 3kg of milk produced and any concentrate not consumed after approximately 1 hour was weighed. The concentrate consisted of soybean meal, 25.0%; oats, 20.0%; shelled corn, 52.5%; defluorinated calcium phosphate, 1.5%; and trace mineralized salt, 1.0%. The trace mineralized salt was guaranteed to contain not less than: 0.228% Mn as manganous oxide, 0.160% Fe as ferrous carbonate, 0.033% Cu as copper oxide, 0.010% Co as cobalt oxide, 0.0075 I as calcium iodate, 0.005% Zn as zinc oxide; 97.8 to 98.8% NaC1 and technical white
1545
1546
O'D~LL ET AL.
mineral oil and iron oxide of unspecified amounts. All animals were fed corn silage ad libitum as one herd. On a dry matter basis, the concentrate contained 7.9% ash, 23.3% crude protein, 7.4% acid-detergent fiber, 3.1% ether extract, 0.78% calcium and 0.99% phosphorus. Corn silage, on a dry matter basis, analyzed 6.4% ash, 8.6% crude protein, 32.3% acid-detergent fiber, 2.0% ether extract, 0.24% calcium and 0.17% phosphorus. Every cow was examined and observed at least twice per week by an experienced veterinary clinician for indications of any abnormalities. Milk weights were recorded daily, and a 24-hour sample was taken from each animal at the end of a 1-week preliminalT, at 2-week intervals for 6 weeks during treatment, and at the end of 1-week post-treatment. Precautions were taken to prevent the milk from contacting any metal. The interior of the milk claw, the milk cock and underside of the milk pail cover were coated with an acrylic resin. After the walls of the pail had been moistened with water, a .008em polyethylene bag was inserted and the top folded around the pail opening and held in place by rubber restraints. The pail, with liner in place, was then slowly filled with water. This procedure forced trapped air to the top of the liner where it was evacuated by releasing the rubber restraints. With the trapped air evacuated, the polyethylene liner strongly adhered to the moistened side of the milk pail resisting being drawn by vacuum to the top of the pail. Samples of milk were removed from the pail by a "plastic" cup and were stored frozen in l-liter polyethylene bottles. F i f t y milliliter samples, in duplicate, from each cow during both the pretreatment period and at the end of 6 weeks' treatment were transferred to 125nfi Erlenmeyer flasks. Samples were dried in a vacumu oven and wet ashed with a sulfuric-perchloric-nitric (1:3:10) acid mixture. Reagent blanks containing the same quantity of acid mixture were prepared identically in duplicate and treated the same as the samples. The p H of the samples was adjusted to approximately 2.5 (recta cresol purple indicator, p H range 1.2-2.8) by putting them in a desiccator containing a small amount of NH4OH. The N t I 3 evolved from the N H 4 0 H was absorbed by the acidified milk samples. When the samples reached the end point, they were transferred to Babcock nfilk test bottles. The nickel in the original 50ml of milk was eomplexed into a 5nil organic phase which was raised into the neck of the Babcock bottle JOURNAL
OF D A I R Y SCIEI~¢E "V'oI~.53, :No. ii
with glass-distilled, deionized water. Aspiration was directly from this organic phase into an atomic absorption spectrophotometer 5 with a standard (10cm slot) burner head. A scale factor of I and slit width of 0.3mm were used. Range was the ultraviolet wavelength 2,320 A. A hollow cathode nickel lamp was used with lamp current at 25mamps. A stable flame was obtained with air flow at 6.0 and acetylene flow at 0.32kg/em 2. Milk was analyzed for fat by the method of Babcock (3), for protein by dye binding procedure (12), and for solids-not-fat by the Mojonnier method (7). Results and Discussion
No abnormality was observed in any cow during the experiment. I n Table 1 the animal performance data for the 3 treatments are presented. Concentrate consumption was comparable for each of the 3 treatment groups indicating no effect of nickel. Likewise, milk production, milk fat, solids-not-fat, and protein were unaffected by the treatments. Average daily milk production during the treatments with 0, 50 and 250 p p m groups, were 93, 93 and 97% of production during the 1 week period before nickel supplementation. A f t e r adjustment by covariance for differences between animals within a group during the pretreatment standardization period, average milk fat tests were 0.20, 0.30 and 0.11% higher for the 0, 50, and 250 p p m nickel groups during the treatments. Daily intakes of supplemental nickel up to 1.8g exerted no statistically significant influence on concentrate intake, milk production, or milk composition. I n earlier work nickel concentrations of 2 and 4 times that in this study rendered the feed much less palatable to dairy calves (8). The lower limit of reliable detectability of the nickel method was 0.1 ppm. Only 6 samples contained as much as 0.1 p p m nickel; all of these were collected during pretreatment. The milk nickel contents (Table 2) are of about the same magnitude as reported by Archibald (1), who concluded that the detected nickel resulted from contamination. Mean nickel contents were identical for each treatment and equal to or less than basal values. I f they were due to contamination, in spite of rigorous precautionary measures, it would indicate that the measures unintentionally improved with time and that very little nickel is secreted into 5Mocle] 303, Perkin-Ehner Corporation, ~orwalk, Conn.
SUPPLEMENTAL
NICKEL
1547
TABLE 1. Effect of supplemental nickel in concentrate on cow performance, a Supplemental nickel, ppm
Concentrate fed (kg/cow per day) Concentrate refused (kg/cow per day) Concentrate consumed (kg/cow per day) Supplemental nickel consumed (mg/cow per day) Body weight change (kg/cow per day) Milk produced Preliminary period (kg/cow per day) Treatment period (kg/cow per day) a F a t in milk Preliminary period (%) Treatment period ( % ) d Protein in milk Preliminary period ( % ) Treatment period (%) a Solids-not-fat in milk Preliminary period (%) Treatment period (%) a
0
50
250
7.76 c 0.45 7.31
7.76
7.76
0.67 24.2 22.0
0.46
0.41
7.30
7.35
365 0.83
1,835 0.83
23.8 22.0
SEb
23.4 23.1
0.68
3.60 3.80
3.36 3.66
3.52 3.63
0.09
3.85 3.95
3.87 3.90
3.75 3.85
0.05
8.75 8.63
8.70 8.55
8.48 8.46
0.10
a Average values for 5 cows per treatment. b Standard error of a treatment mean. c None of the measures in this table were significant at the 5% level of probability. d Adjusted by covariance for differences in milk and milk components during standardization period. milk by the cow. 7However, nickel, like cadmium (6), is not increased significantly in milk by feeding large supplemental amounts. During the last treatment week, the average nickel intake was 1,792mg for cows fed 250 ppm nickel in the concentrate. None of the samples contained as much as 0.1 ppm, the reliability limit of the method. A concentration of 0.1 ppm would represen~ the transfer of 2.ling of nickel into the milk; thus none of the ana-
lyzed milk samples of this group of animals could have contained a quantity of nickel that would have been present had 0.12% of the supplemental nickel been secreted into the milk. While our data failed to define more exactly the nickel content of milk, they add to an understanding of this subject. Milk from cows fed high nickel supplements contained no more ( < 0.1 ppm) and probably contains less nickel
TABLE 2. Nickel in milk from cows fed supplemental nickel in concentrate. Nickel supplementation in concentrate Animal number
0 ppm
50 ppm
Basal a
Treatment b
Basal
0.03 0.07 0.00 0.15 0.15
0.03 0.00 0.04 0.03 0.02
0.08
0.02
250 ppnl
Treatment
Basal
Treatment
0.11 0.19 0.12 0.09 0.20
0.01 0.01 0.02 0.02 0.05
0.01 0.02 0.08 0.00 0.00
0.05 0.01 0.03 0.00 0.00
0.14
0.02
0.02
0.02
(ppm) 1 2 3 4 5 Average
a Basal, concentrate without supplemental nickel. b Treatment, concentrate with supplemental nickel. JOURNAL OF DAIRY SCIENCE VOL, 53, NO. 11
1548
O ' D E L L ET AL.
t h a n milk processed t h r o u g h stainless steel e q u i p m e n t in a n y d a i r y p l a n t . Two samples of p a s t e u r i z e d , homogenized milk f r o m a v e n d ing machine were analyzed f o r nickel. N e i t h e r c o n t a i n e d as much as 0.1 p p m nickel. Nickel in c o n c e n t r a t e at 250 p p m g r e a t l y exceeds the a m o u n t t h a t a l a c t a t i n g cow would consume in feeds u n d e r a n y conceivable n o r m a l circumstances. Thus it is most unlikely t h a t nickel in the cow's diet would add m e a s u r a b l y to the nickel content of milk. References (1) Archibald, J. G. 1949. Nickel in cows' milk. J. Dairy Sci. 32: 877. (2) Archibald, J. G. 1958. Trace elements in milk: A review, p a r t 11. Dairy Sei. Abst. 20: 800. (3) Association of Official Agricultural Chemists. 1965. Official Methods of Analysis. 10th cd., Washington, D. C. (4) Chang, A. T., and G. D. Sherman. 1953. The nickel content of some Hawaiian soils and plants and the relation of nickel to plant growth. Hawaii Agr. Exp. Sta. Tech. Bull., 19. (5) Crookc, W. M., and A. H. Knight. ]955. The relationship between nickel toxicity symptoms and the absorption of iron and nickel. Ann. Appl. Biol. 43: 454. (6) Miller, W. J., Beverly Lampp, G. W.
JOI~,NAL O]t I)JLIRY SOIENOZ ~OL. 53, NO. 11
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
Powell, C. A. Salotti, and D. M. Blackmon. 1967. Influence of a high level of dietary cadmium on cadmium content in milk, excretion, and cow performance. J. Dairy Sci. 50 : 1404. Mojonnier, T., and H. C. Troy. 1925. The Technical Control of Dairy Products. Mojonnier Bros. Co., Chicago, Ill. 2nd ed. pp. 122-131. O'De]], G. D., W. J. Miller, S. L. Moore, and W. A. King. 1970. Effect of nickel as the chloride and the carbonate on pa]atability of cattle feed. J. Dairy Sci., 53:1266. Phatak, S. S., and V. N. Patwardham. 1950. Toxicity of nickel. J. Sci. Ind. Res. 9b: 70. Phatak, S. S., and V. N. Patwardham. 1952. Toxicity of nickel; accumulation of nickel in rats on nickel-containlng diets and its elimination. J. Sci. Ind. Res., l l b : 172. Sehroeder, H. A., J. J. Balassa, and I. H. Tipton. 1962. Abnormal trace metals in man-nickel. J. Chron. Dis. 1 5 : 5 1 . ~anderzant, C., and W. R. Temmison. ]96]. Estimation of the protein content of milk by dye binding with buffalo black. Food Teeh., 15: 63. Weber, C. W., and B. L. Reid. 1968. Nickel toxicity in growing chicks. J. Nutrition 95: 612. Weber, C. W., and B. L. Reid. 1969. Nickel toxicity in young growing mice. J. Animal Sci., 28: 620.
Department of Dairy Science, Clemson University Clemson, South Carolina 2963] and Dairy Science Department, University of Georgia Athens 30601 Abstract
or sulfate for chicks (13), 1,100 ppm as the acetate for mice (14), but rats tolerated u 1) to 1,000 ppm as the carbonate or the metal without apparent toxicity (9,10). Generally plants contain less nickel (4,11), usually 0 to 5 ppm but often many times more (4). The normal nickel content in nfilk has not been established but conflicting reports have been published (2). Archibald (1) fed 145mg of elemental nickel daily as niekelous chloride to lactating dairy cows and failed to detect an inc.rease of nickel in milk. The objectives of this study were to ascertain the effect on animal performance and on nickel, fat, protein, and solids-not-fat of milk when lactating cows were fed nickel in amounts lower than those at which toxicity symptoms have been observed with monogastric animals (13,14) but greatly exceeding amounts used in a lactation experiment (1).
Three concentrations of nickel carbonate were fed to 3 groups of 5 lactating dairy cows each. Nickel carbonate was mixed in the concentrate ration at 0, 50 and 250 ppm of elemental nickel and concentrate fed at a ratio of lkg per 3kg of milk produced. Average daily consumption of supplemental nickel per cow was 0, 365 and 1,835mg, respectively. No significant effect on milk production, lnilk composition, animal health or feed consumption was observed. Within the detectable limits of the analytical procedure, feeding nickel did not increase nickel in milk and never exceeded that in plant processed milk. None of the milk samples from cows fed 250 ppm nickel contained as much as 0.1 ppm nickel, which was the lower reliability limit of the procedure. Less than 0.12% of the supplemental nickel appeared in the milk.
Experimental Procedures
Introduction
Knowledge relating to milk content of substances which are toxic or potentially toxic is highly desirable. Also a nmeh better understanding of the principles which regulate the transfer of many trace substances from feed into milk is needed. Nickel is toxic at 40 to 60 ppm for plants (4,5), 700 ppm as the acetate :Received for publication March 24, 1970. 1 Technical contribution no. 850, South Carolina Agricultural Experiment Station. Published by permission of the Director. University of Georgia, College of Agricultural Experiment Stations, Journal paper no. 753, College Station, Athens. 2 Department of Dairy Science, Clemson University. 3 Dairy Science Department, The University of Georgia. 4 Agricultural Chemical Services, Clemson University.
Fifteen multiparous, lactating dairy cows with daily production between 16.5 and 30.0kg were approximately equalized into groups of 3 on age, weight, milk production and stage of lactation. These were randomly allotted to each of 3 treatments. Niekelous carbonate (NiC03) was added to the concentrate to provide 0, 50, and 250 ppm of nickel on an as-fed basis. Nickel carbonate is relatively insoluble in water but was determined to be readily soluble in rumen fluid. One kilogram of concentrate was fed for each 3kg of milk produced and any concentrate not consumed after approximately 1 hour was weighed. The concentrate consisted of soybean meal, 25.0%; oats, 20.0%; shelled corn, 52.5%; defluorinated calcium phosphate, 1.5%; and trace mineralized salt, 1.0%. The trace mineralized salt was guaranteed to contain not less than: 0.228% Mn as manganous oxide, 0.160% Fe as ferrous carbonate, 0.033% Cu as copper oxide, 0.010% Co as cobalt oxide, 0.0075 I as calcium iodate, 0.005% Zn as zinc oxide; 97.8 to 98.8% NaC1 and technical white
1545
1546
O'D~LL ET AL.
mineral oil and iron oxide of unspecified amounts. All animals were fed corn silage ad libitum as one herd. On a dry matter basis, the concentrate contained 7.9% ash, 23.3% crude protein, 7.4% acid-detergent fiber, 3.1% ether extract, 0.78% calcium and 0.99% phosphorus. Corn silage, on a dry matter basis, analyzed 6.4% ash, 8.6% crude protein, 32.3% acid-detergent fiber, 2.0% ether extract, 0.24% calcium and 0.17% phosphorus. Every cow was examined and observed at least twice per week by an experienced veterinary clinician for indications of any abnormalities. Milk weights were recorded daily, and a 24-hour sample was taken from each animal at the end of a 1-week preliminalT, at 2-week intervals for 6 weeks during treatment, and at the end of 1-week post-treatment. Precautions were taken to prevent the milk from contacting any metal. The interior of the milk claw, the milk cock and underside of the milk pail cover were coated with an acrylic resin. After the walls of the pail had been moistened with water, a .008em polyethylene bag was inserted and the top folded around the pail opening and held in place by rubber restraints. The pail, with liner in place, was then slowly filled with water. This procedure forced trapped air to the top of the liner where it was evacuated by releasing the rubber restraints. With the trapped air evacuated, the polyethylene liner strongly adhered to the moistened side of the milk pail resisting being drawn by vacuum to the top of the pail. Samples of milk were removed from the pail by a "plastic" cup and were stored frozen in l-liter polyethylene bottles. F i f t y milliliter samples, in duplicate, from each cow during both the pretreatment period and at the end of 6 weeks' treatment were transferred to 125nfi Erlenmeyer flasks. Samples were dried in a vacumu oven and wet ashed with a sulfuric-perchloric-nitric (1:3:10) acid mixture. Reagent blanks containing the same quantity of acid mixture were prepared identically in duplicate and treated the same as the samples. The p H of the samples was adjusted to approximately 2.5 (recta cresol purple indicator, p H range 1.2-2.8) by putting them in a desiccator containing a small amount of NH4OH. The N t I 3 evolved from the N H 4 0 H was absorbed by the acidified milk samples. When the samples reached the end point, they were transferred to Babcock nfilk test bottles. The nickel in the original 50ml of milk was eomplexed into a 5nil organic phase which was raised into the neck of the Babcock bottle JOURNAL
OF D A I R Y SCIEI~¢E "V'oI~.53, :No. ii
with glass-distilled, deionized water. Aspiration was directly from this organic phase into an atomic absorption spectrophotometer 5 with a standard (10cm slot) burner head. A scale factor of I and slit width of 0.3mm were used. Range was the ultraviolet wavelength 2,320 A. A hollow cathode nickel lamp was used with lamp current at 25mamps. A stable flame was obtained with air flow at 6.0 and acetylene flow at 0.32kg/em 2. Milk was analyzed for fat by the method of Babcock (3), for protein by dye binding procedure (12), and for solids-not-fat by the Mojonnier method (7). Results and Discussion
No abnormality was observed in any cow during the experiment. I n Table 1 the animal performance data for the 3 treatments are presented. Concentrate consumption was comparable for each of the 3 treatment groups indicating no effect of nickel. Likewise, milk production, milk fat, solids-not-fat, and protein were unaffected by the treatments. Average daily milk production during the treatments with 0, 50 and 250 p p m groups, were 93, 93 and 97% of production during the 1 week period before nickel supplementation. A f t e r adjustment by covariance for differences between animals within a group during the pretreatment standardization period, average milk fat tests were 0.20, 0.30 and 0.11% higher for the 0, 50, and 250 p p m nickel groups during the treatments. Daily intakes of supplemental nickel up to 1.8g exerted no statistically significant influence on concentrate intake, milk production, or milk composition. I n earlier work nickel concentrations of 2 and 4 times that in this study rendered the feed much less palatable to dairy calves (8). The lower limit of reliable detectability of the nickel method was 0.1 ppm. Only 6 samples contained as much as 0.1 p p m nickel; all of these were collected during pretreatment. The milk nickel contents (Table 2) are of about the same magnitude as reported by Archibald (1), who concluded that the detected nickel resulted from contamination. Mean nickel contents were identical for each treatment and equal to or less than basal values. I f they were due to contamination, in spite of rigorous precautionary measures, it would indicate that the measures unintentionally improved with time and that very little nickel is secreted into 5Mocle] 303, Perkin-Ehner Corporation, ~orwalk, Conn.
SUPPLEMENTAL
NICKEL
1547
TABLE 1. Effect of supplemental nickel in concentrate on cow performance, a Supplemental nickel, ppm
Concentrate fed (kg/cow per day) Concentrate refused (kg/cow per day) Concentrate consumed (kg/cow per day) Supplemental nickel consumed (mg/cow per day) Body weight change (kg/cow per day) Milk produced Preliminary period (kg/cow per day) Treatment period (kg/cow per day) a F a t in milk Preliminary period (%) Treatment period ( % ) d Protein in milk Preliminary period ( % ) Treatment period (%) a Solids-not-fat in milk Preliminary period (%) Treatment period (%) a
0
50
250
7.76 c 0.45 7.31
7.76
7.76
0.67 24.2 22.0
0.46
0.41
7.30
7.35
365 0.83
1,835 0.83
23.8 22.0
SEb
23.4 23.1
0.68
3.60 3.80
3.36 3.66
3.52 3.63
0.09
3.85 3.95
3.87 3.90
3.75 3.85
0.05
8.75 8.63
8.70 8.55
8.48 8.46
0.10
a Average values for 5 cows per treatment. b Standard error of a treatment mean. c None of the measures in this table were significant at the 5% level of probability. d Adjusted by covariance for differences in milk and milk components during standardization period. milk by the cow. 7However, nickel, like cadmium (6), is not increased significantly in milk by feeding large supplemental amounts. During the last treatment week, the average nickel intake was 1,792mg for cows fed 250 ppm nickel in the concentrate. None of the samples contained as much as 0.1 ppm, the reliability limit of the method. A concentration of 0.1 ppm would represen~ the transfer of 2.ling of nickel into the milk; thus none of the ana-
lyzed milk samples of this group of animals could have contained a quantity of nickel that would have been present had 0.12% of the supplemental nickel been secreted into the milk. While our data failed to define more exactly the nickel content of milk, they add to an understanding of this subject. Milk from cows fed high nickel supplements contained no more ( < 0.1 ppm) and probably contains less nickel
TABLE 2. Nickel in milk from cows fed supplemental nickel in concentrate. Nickel supplementation in concentrate Animal number
0 ppm
50 ppm
Basal a
Treatment b
Basal
0.03 0.07 0.00 0.15 0.15
0.03 0.00 0.04 0.03 0.02
0.08
0.02
250 ppnl
Treatment
Basal
Treatment
0.11 0.19 0.12 0.09 0.20
0.01 0.01 0.02 0.02 0.05
0.01 0.02 0.08 0.00 0.00
0.05 0.01 0.03 0.00 0.00
0.14
0.02
0.02
0.02
(ppm) 1 2 3 4 5 Average
a Basal, concentrate without supplemental nickel. b Treatment, concentrate with supplemental nickel. JOURNAL OF DAIRY SCIENCE VOL, 53, NO. 11
1548
O ' D E L L ET AL.
t h a n milk processed t h r o u g h stainless steel e q u i p m e n t in a n y d a i r y p l a n t . Two samples of p a s t e u r i z e d , homogenized milk f r o m a v e n d ing machine were analyzed f o r nickel. N e i t h e r c o n t a i n e d as much as 0.1 p p m nickel. Nickel in c o n c e n t r a t e at 250 p p m g r e a t l y exceeds the a m o u n t t h a t a l a c t a t i n g cow would consume in feeds u n d e r a n y conceivable n o r m a l circumstances. Thus it is most unlikely t h a t nickel in the cow's diet would add m e a s u r a b l y to the nickel content of milk. References (1) Archibald, J. G. 1949. Nickel in cows' milk. J. Dairy Sci. 32: 877. (2) Archibald, J. G. 1958. Trace elements in milk: A review, p a r t 11. Dairy Sei. Abst. 20: 800. (3) Association of Official Agricultural Chemists. 1965. Official Methods of Analysis. 10th cd., Washington, D. C. (4) Chang, A. T., and G. D. Sherman. 1953. The nickel content of some Hawaiian soils and plants and the relation of nickel to plant growth. Hawaii Agr. Exp. Sta. Tech. Bull., 19. (5) Crookc, W. M., and A. H. Knight. ]955. The relationship between nickel toxicity symptoms and the absorption of iron and nickel. Ann. Appl. Biol. 43: 454. (6) Miller, W. J., Beverly Lampp, G. W.
JOI~,NAL O]t I)JLIRY SOIENOZ ~OL. 53, NO. 11
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
Powell, C. A. Salotti, and D. M. Blackmon. 1967. Influence of a high level of dietary cadmium on cadmium content in milk, excretion, and cow performance. J. Dairy Sci. 50 : 1404. Mojonnier, T., and H. C. Troy. 1925. The Technical Control of Dairy Products. Mojonnier Bros. Co., Chicago, Ill. 2nd ed. pp. 122-131. O'De]], G. D., W. J. Miller, S. L. Moore, and W. A. King. 1970. Effect of nickel as the chloride and the carbonate on pa]atability of cattle feed. J. Dairy Sci., 53:1266. Phatak, S. S., and V. N. Patwardham. 1950. Toxicity of nickel. J. Sci. Ind. Res. 9b: 70. Phatak, S. S., and V. N. Patwardham. 1952. Toxicity of nickel; accumulation of nickel in rats on nickel-containlng diets and its elimination. J. Sci. Ind. Res., l l b : 172. Sehroeder, H. A., J. J. Balassa, and I. H. Tipton. 1962. Abnormal trace metals in man-nickel. J. Chron. Dis. 1 5 : 5 1 . ~anderzant, C., and W. R. Temmison. ]96]. Estimation of the protein content of milk by dye binding with buffalo black. Food Teeh., 15: 63. Weber, C. W., and B. L. Reid. 1968. Nickel toxicity in growing chicks. J. Nutrition 95: 612. Weber, C. W., and B. L. Reid. 1969. Nickel toxicity in young growing mice. J. Animal Sci., 28: 620.