Blood and Milk Progesterone in Pregnant and Nonpregnant Buffalo S. K, BATRA, R. C. A R O R A , N. K. BACHLAUS, and R. S. P A N D E Y Dairy Chemistry Division National Dairy Research Institute Karnal (india) 132001 ABSTRACT
terone in blood and milk of buffalo after insemination till early pregnancy.
Changes in progesterone concentration of blood and milk were measured by radioimmunoassay in 10 Murrah buffalo up to 40 days after insemination. Progesterone concentration in blood plasma at estrus was .1 ng/ml which rose to a peak of 3.6 ng/ml on day 13)It continued to increase in animals that conceived but dropped to .6 ng/ml on 3 days before next estrus in those that failed to conceive. The average concentration of progesterone in milk was .5 ng/ml at estrus; it increased to 18 ng/ml on day 15, and thereafter it declined to 4.4 ng/ml 3 days preceding next estrus in nonpregnant animals. In pregnant animals, it was maintained and elevated further to 24.8 ng/ml on day 37. Progesterone in milk was four to five times higher than in blood plasma.
M A T E R I A L S AND METHODS Sampling
INTRODUCTION
Progesterone concentration in blood and milk has been estimated by radioimmunoassay or competitive protein binding techniques. The concentration in milk is similar or higher than that of blood plasma (3, 9, 10). Progesterone serves as a valuable indication of the concentration of hormones reaching target organs. Concentration of progesterone in blood and milk at 20 to 24 days postbreeding has been used as a tool for an early estimate of pregnancy in cattle (5, 7) and buffalo (1). Although progesterone in milk is higher than in blood (4), changes in progesterone tend to reflect its concentration in blood. The study of hormones in the blood and milk of buffalo apparently has received little or no attention. Our aim was to estimate proges-
Received October 30, 1978. 1979 J Dairy Science 62:1390-1393
Ten lactating buffalo were selected from the herd maintained at the Institute. The animals were inseminated about 8 h after detection of estrus, and later they were classified into pregnant and nonpregnant groups depending upon their return to estrus. Blood samples (10 ml heparinized) were collected daily via jugular venipuncture from day 0 (day of insemination) to day 5, followed by collection on alternate days until day 17. Again the sampling was daily until day 25 or the animal's return to estrus, whichever occurred first. The animals which did not return to estrus were followed for blood collection on every 4th day until day 40 of pregnancy. Blood was collected rapidly in tubes packed in ice and centrifuged at 4 C within 1 h of collection, and plasma was stored at - 2 0 C pending analysis. Pooled milk samples were taken at evening milking as per schedule followed for blood collection. The samples were preserved with .01% formalin and stored at 4 C until analyzed. Progesterone Assay
Progesterone in blood plasma was measured by radioimmunoassay (1). Milk progesterone also was measured by similar procedure except that the extraction step was eliminated. Milk samples were kept at room temperature for 1 h, vortexed, and 50 ~1 in duplicate were diluted with 150 #1 of phosphate buffer saline (PBS) pH 7.0. At the same time a series of standard concentrations of progesterone were prepared containing 5, 10, 20, 40, 80, 160, 320, 640, 1280, 2560, and 5120 pg in 100 #1 of buffer and 50 til of hormone free milk. The assay tubes containing unknown samples and standards were combined with .1 ml mixture of
1390
BLOOD AND MILK PROGESTERONE [1,2,6,73 H] progesterone and antiserum (dilution at 16,000). The resulting mixture of milk, labeled progesterone, and antiserum was incubated at 60 C for 10 min and at 30 C for 30 min before addition of .5 ml of 1% charcoal suspension to separate free steroids from antibody-bound progesterone. Contents of the tubes were mixed and allowed to equilibrate for 10 min and centrifuged at 3000 rpm for 5 min at 4 C. The supernatant was decanted into mini liquid scintillation counting (LSC) vials containing 5 ml of scintillation fluid [1 liter toluene, 4.5 g PPO (2,5 diphenyl oxazole) and .1 g POPOP (phenyl oxazolyl phenyl-oxazolylphenyl)]. Validity of the assay was determined by observing the recovery of known amounts of progesterone added in hormone-free (by charcoal treatment) 200 #1 blood plasma and 50 /21 of milk as in Table 1. The sensitivity of the method in limit of detection for blood and milk was 5 and 4.1 pg. Coefficients of intraand interassay variation of blood in the same as well as in four different assays of pooled female blood plasma was 14.6 and 15.1%. All estimations of progesterone in milk were in a single assay, and variation within assay was 12.8%. The specificity of the progesterone antiserum was reported by Arora et al. (1). RESULTS
Five of the ten buffalo were diagnosed pregnant by rectal palpation at 48 to 50 days after insemination. Mean concentrations of progesterone in plasma and milk are in Tables 2 and 3 for pregnant and nonpregnant animals, respectively. Since the period for return to estrus was not exactly the same length (19 to 26 days), the concentrations for the first 19
1391
days after insemination and 3 days preceding next estrus are in tables. P-rogesterone in blood plasma increased and decreased coinciding with the growth and regression of the corpus luteum, Progesterone was lowest on the day of insemination (day O) and remained low until 3 days when it began to increase, reaching a peak on day 13 in nonpregnant animals. Thereafter it declined gradually followed by a rapid fall on day 2, thereby attaining a low of .10 -+ .07 ng/ml at the onset of subsequent estrus. However, unlike nonpregnant buffalo, progesterone in pregnant animals did not drop after day 13 but was maintained and elevated a little to an average of 4.13 +-.73 ng/ml on day 25 after insemination. The pattern of change in milk progesterone of pregnant and nonpregnant buffalo was similar to progesterone in plasma. Over all days, the progesterone concentration in milk was approximately four to five times (7.67 and 9.19 ml) that in blood plasma of nonpregnant and pregnant (1.33 and 2.45 n g / m l ) b u f f a l o . The progesterone concentration in blood and milk were correlated in pregnant and nonpregnant (.98 and .99) animals. DISCUSSION
Progesterone concentrations of plasma in lactating buffalo were similar to those in buffalo heifers (2). Furthermore, progesterone concentration in milk was four to five times higher than that of blood plasma which agrees with (4) in cattle. In addition, the close correlation between progesterone concentrations in milk and blood plasma suggests that it may be useful to measure milk progesterone in clinical cases of reproductive abnormalities in buffalo. It is not clear whether the high progesterone
TABLE 1. Direct evaluation of radioimmunoassay of progesterone for accuracy. Number of replicate
Progesterone added (ng)
Progesterone recovered (ng) Blood plasma Milk Mean SE Mean SE
Percentage recovery Blood Plasma Milk
8 8 8 8
.25 .50 1.0 2.0
.28 .55 1.06 2.06
112 110 106 103
.04 .03 .06 .04
.27 .53 1.02 2.04
.04 .06 .05 .05
108 106 103 102
Journal of Dairy Science Vol. 62, No. 9, 1979
1392
BATRA ET AL.
TABLE 2. Progesterone concentration (ng/ml) in blood plasma and milk of n0npregnant buffalo,
TABLE 3. Progesterone concentration (ng/ml) in blood plasma and milk of pregnant buffalo.
Day of estrous cycle
Day of pregnancy
0a 1 2 3 4 5 7 9 11 13 15 17 18 19 3 --2 1 0
Blood plasma Mean SE .06 .08 .11 .29 .43 .51 1.4 2.2 2.9 3.8 3.7 3.0 2.4 1.8 .62 .42 .30 .10
.03 .07 .04 .15 .11 .14 .27 .64 .79 1.8 1.7 1.7 1.2 1.2 .16 .09 .08 .07
Milk Mean .38 .98 1.6 2.7 3.2 4.4 7.1 13.3 14.5 18.0 18.5 17.5 15.3 13.6 4.4 1.8 .53 .41
SE .12 .15 .14 .24 .31 .52 1.2 .71 1.4 1.5 1.4 .88 1.9 1.7 .13 .34 .13 .12
aDay 0 = Day of insemination.
in milk is due to t r a n s f e r o f p r o g e s t e r o n e f r o m b l o o d to milk or its possible s y n t h e s i s b y m a m m a r y tissue. Heap et al. (8) suggested p r o g e s t e r o n e in c o w s ' milk was a t t r i b u t e d to its diffusion against c o n c e n t r a t i o n g r a d i e n t f r o m b l o o d and c o n c l u d e d t h a t p r o g e s t e r o n e measured in milk was higher, p r o b a b l y as a result o f t h e lipid solubility o f t h e s t e r o i d . However, t h e r e is e v i d e n c e for synthesis o f p r o g e s t e r o n e in m a m m a r y tissue o f goat f r o m t h e infusion o f [3 H] p r e g n a n o l o n e (12) w h i c h indicates t h a t t h e m a m m a r y tissue has e n z y m e s to s y n t h e s i z e p r o g e s t e r o n e . P o p e et al. (11) o b s e r v e d average p r o g e s t e r o n e .86 n g / m l for w h o l e milk and .14 n g / m l for fat free milk. Similarly G i n t h e r et al. (5) f o u n d changes in fat c o n c e n t r a t i o n were closely parallel to p r o g e s t e r o n e c o n c e n t r a t i o n w h e n samples w e r e collected at d i f f e r e n t t i m e s o f t h e day. Thus, it appears t h a t higher milk p r o g e s t e r o n e in c o m p a r i s o n with cows m a y be i n f l u e n c e d b y t h e higher p e r c e n t a g e o f fat in b u f f a l o milk. It generally is agreed t h a t c o n c e n t r a t i o n s o f p r o g e s t e r o n e in b l o o d and milk provide estim a t e s o f luteal f u n c t i o n during t h e r e p r o d u c t i v e cycle. The m i d c y c l e rise o f p r o g e s t e r i n e in plasma and milk appears to result f r o m luteiniJournal of Dairy Science Vol. 62, No. 9, 1979
0a 1 2 3 4 5 7 9 11 13 15 17 18 19 20 21 22 23 24 25 29 33 37 4o
Blood plasma
Milk
Mean
SE
Mean
SE
.08 .07 .18 .34 .46 .57 1.02 2.2 3.0 3.3 2.9 3.7 3.0 3.4 4.0 3.3 3.1 3.4 3.5 4.1 3.9 3.0 3.4 3.2
.03 .01 .06 .09 .08 .10 .09 .98 1.0 .73 .81 .76 .58 .94 .79 .76 .82 1.1 .99 .73 .74 .67 .95 .88
.54 1.7 2.5 3.5 4.1 5.5 9.6 13.3 17.2 20.2 17.3 19.8 21.2 22.2 20.4 21.9 22.8 22.2 20.6 24.4 23.9 20.1 24.7 22.8
.09 .24 .29 .26 .27 .65 1.7 1.7 1.7 1.2 1.9 1.1 1.9 2.1 1.2 1.7 .93 .81 .81 .79 .68 1.8 1.6 .50
aDay 0 = Day of insemination.
zation after o v u l a t i o n and s u b s e q u e n t progest e r o n e secretion b y t h e c o r p u s l u t e u m . The m e a n results f r o m Tables 2 and 3 i n d i c a t e a d i f f e r e n c e in p r o g e s t e r o n e c o n c e n t r a t i o n bet w e e n day 20 t o 25, suggesting t h a t milk p r o g e s t e r o n e m a y provide a m o r e reliable t e s t for early p r e g n a n c y diagnosis in buffalo as in c o w s (11). ACKNOWLEDGMENTS We th~mk D. S u n d a r e s a n , Director, National Dairy Research Institute, for s h o w i n g keen i n t e r e s t in this s t u d y and providing necessary facilities. We also are i n d e b t e d t o B.J.A. Furr for t h e g e n e r o u s gift o f p r o g e s t e r o n e a n t i s e r u m used in assay o f p r o g e s t e r o n e . REFERENCES 1 Arora, R. C., N. K. Bachlaus, A. Prasad, and R. S. Pandey. 1979. Plasma progesterone level and early pregnancy diagnosis in buffaloes heifers. Ind.
BLOOD AND MILK PROGESTERONE
J. Exp. Biol. 17:124. 2 Bachlaus, N. K., R. C. Arora, A. Prasad, and R. S. Pandey. 1979. Plasma level o f gonadal h o r m o n e s in cycling buffalo heifers. Ind. J. Exp. Biol. (In press). 3 Darling, J.A.B., R. W. Killey, A. tt. Laing, and R. A. Harkners. 1972. The isolation and identification of progesterone obtained from cow's milk during pregnancy. J. Endocrinol. 54: 347. 4 Ginther, O. J., L. C. Nuti, B. C. Wentworth, and W. J. Tyler. 1974. Progesterone concentration in milk and blood during pregnancy in cows. Proc. Soc. Exp. Biol. Med. 146: 354. 5 Ginther, O. J., L. C. Nuti, M. C. Garcia, B. C. Wentworth, and W. J. Tyler. 1976. Factors affecting progesterone concentration in cow's milk and dairy products. J. Anita. Sci. 42:155. 6 Gunzler, O., L. Korndorfer, H. Lohoff, R. Hamburger, and B. Hoffman. 1975. Practical experience in the determination of progesterone in milk as an indicator of fertility of cows. Tieraztliche Umschaw. 30;III. 7 Heap, R. B., M. Gwyn, J. A. Laing, and D. E.
8
9
10
11
12
1393
Wahers. 1973. Pregnancy diagnosis in cows: Changes in milk progesterone concentration measured during estrous cycle, pregnancy measured by rapid radioimmunoassay. J. Agr. Res. 81:151. Heap, R. B., A. Henville, and J. L. Linzell. 1975. Metabolic clearance rate, production rate and m a m m a r y uptake and metabolism of progesterone in cows. J. Endocrinol. 66:239. Hoffman, B., and R. Hamburger. 1973. Progesterone in milk: Determination by m e a n s of R[A: relationship between CL function and fat concentration. Zuchthygiene 8:154. Laingh, J. A., and R. B. Heap. 1971. The concentration of progesterone in the milk of cow during reproductive cycle. Brit. Vet. J. 127:XIX. Pope, G. S., I. Majzlik, P.J.H. Nail, and J. D. Leaver. 1976. Use of progesterone concentration in plasma and milk in the diagnosis of pregnancy in domestic cattle. Brit. Vet. J. 132:497. Slotin, C. A., R. B. Heap, J. M. Christiansen, and J. A. Linzell. 1970. Synthesis of progesterone by m a m m a r y gland of goat. Nature (London) 225:385.
Journal of Dairy Science Vol. 62, No. 9, 1979
terone in blood and milk of buffalo after insemination till early pregnancy.
Changes in progesterone concentration of blood and milk were measured by radioimmunoassay in 10 Murrah buffalo up to 40 days after insemination. Progesterone concentration in blood plasma at estrus was .1 ng/ml which rose to a peak of 3.6 ng/ml on day 13)It continued to increase in animals that conceived but dropped to .6 ng/ml on 3 days before next estrus in those that failed to conceive. The average concentration of progesterone in milk was .5 ng/ml at estrus; it increased to 18 ng/ml on day 15, and thereafter it declined to 4.4 ng/ml 3 days preceding next estrus in nonpregnant animals. In pregnant animals, it was maintained and elevated further to 24.8 ng/ml on day 37. Progesterone in milk was four to five times higher than in blood plasma.
M A T E R I A L S AND METHODS Sampling
INTRODUCTION
Progesterone concentration in blood and milk has been estimated by radioimmunoassay or competitive protein binding techniques. The concentration in milk is similar or higher than that of blood plasma (3, 9, 10). Progesterone serves as a valuable indication of the concentration of hormones reaching target organs. Concentration of progesterone in blood and milk at 20 to 24 days postbreeding has been used as a tool for an early estimate of pregnancy in cattle (5, 7) and buffalo (1). Although progesterone in milk is higher than in blood (4), changes in progesterone tend to reflect its concentration in blood. The study of hormones in the blood and milk of buffalo apparently has received little or no attention. Our aim was to estimate proges-
Received October 30, 1978. 1979 J Dairy Science 62:1390-1393
Ten lactating buffalo were selected from the herd maintained at the Institute. The animals were inseminated about 8 h after detection of estrus, and later they were classified into pregnant and nonpregnant groups depending upon their return to estrus. Blood samples (10 ml heparinized) were collected daily via jugular venipuncture from day 0 (day of insemination) to day 5, followed by collection on alternate days until day 17. Again the sampling was daily until day 25 or the animal's return to estrus, whichever occurred first. The animals which did not return to estrus were followed for blood collection on every 4th day until day 40 of pregnancy. Blood was collected rapidly in tubes packed in ice and centrifuged at 4 C within 1 h of collection, and plasma was stored at - 2 0 C pending analysis. Pooled milk samples were taken at evening milking as per schedule followed for blood collection. The samples were preserved with .01% formalin and stored at 4 C until analyzed. Progesterone Assay
Progesterone in blood plasma was measured by radioimmunoassay (1). Milk progesterone also was measured by similar procedure except that the extraction step was eliminated. Milk samples were kept at room temperature for 1 h, vortexed, and 50 ~1 in duplicate were diluted with 150 #1 of phosphate buffer saline (PBS) pH 7.0. At the same time a series of standard concentrations of progesterone were prepared containing 5, 10, 20, 40, 80, 160, 320, 640, 1280, 2560, and 5120 pg in 100 #1 of buffer and 50 til of hormone free milk. The assay tubes containing unknown samples and standards were combined with .1 ml mixture of
1390
BLOOD AND MILK PROGESTERONE [1,2,6,73 H] progesterone and antiserum (dilution at 16,000). The resulting mixture of milk, labeled progesterone, and antiserum was incubated at 60 C for 10 min and at 30 C for 30 min before addition of .5 ml of 1% charcoal suspension to separate free steroids from antibody-bound progesterone. Contents of the tubes were mixed and allowed to equilibrate for 10 min and centrifuged at 3000 rpm for 5 min at 4 C. The supernatant was decanted into mini liquid scintillation counting (LSC) vials containing 5 ml of scintillation fluid [1 liter toluene, 4.5 g PPO (2,5 diphenyl oxazole) and .1 g POPOP (phenyl oxazolyl phenyl-oxazolylphenyl)]. Validity of the assay was determined by observing the recovery of known amounts of progesterone added in hormone-free (by charcoal treatment) 200 #1 blood plasma and 50 /21 of milk as in Table 1. The sensitivity of the method in limit of detection for blood and milk was 5 and 4.1 pg. Coefficients of intraand interassay variation of blood in the same as well as in four different assays of pooled female blood plasma was 14.6 and 15.1%. All estimations of progesterone in milk were in a single assay, and variation within assay was 12.8%. The specificity of the progesterone antiserum was reported by Arora et al. (1). RESULTS
Five of the ten buffalo were diagnosed pregnant by rectal palpation at 48 to 50 days after insemination. Mean concentrations of progesterone in plasma and milk are in Tables 2 and 3 for pregnant and nonpregnant animals, respectively. Since the period for return to estrus was not exactly the same length (19 to 26 days), the concentrations for the first 19
1391
days after insemination and 3 days preceding next estrus are in tables. P-rogesterone in blood plasma increased and decreased coinciding with the growth and regression of the corpus luteum, Progesterone was lowest on the day of insemination (day O) and remained low until 3 days when it began to increase, reaching a peak on day 13 in nonpregnant animals. Thereafter it declined gradually followed by a rapid fall on day 2, thereby attaining a low of .10 -+ .07 ng/ml at the onset of subsequent estrus. However, unlike nonpregnant buffalo, progesterone in pregnant animals did not drop after day 13 but was maintained and elevated a little to an average of 4.13 +-.73 ng/ml on day 25 after insemination. The pattern of change in milk progesterone of pregnant and nonpregnant buffalo was similar to progesterone in plasma. Over all days, the progesterone concentration in milk was approximately four to five times (7.67 and 9.19 ml) that in blood plasma of nonpregnant and pregnant (1.33 and 2.45 n g / m l ) b u f f a l o . The progesterone concentration in blood and milk were correlated in pregnant and nonpregnant (.98 and .99) animals. DISCUSSION
Progesterone concentrations of plasma in lactating buffalo were similar to those in buffalo heifers (2). Furthermore, progesterone concentration in milk was four to five times higher than that of blood plasma which agrees with (4) in cattle. In addition, the close correlation between progesterone concentrations in milk and blood plasma suggests that it may be useful to measure milk progesterone in clinical cases of reproductive abnormalities in buffalo. It is not clear whether the high progesterone
TABLE 1. Direct evaluation of radioimmunoassay of progesterone for accuracy. Number of replicate
Progesterone added (ng)
Progesterone recovered (ng) Blood plasma Milk Mean SE Mean SE
Percentage recovery Blood Plasma Milk
8 8 8 8
.25 .50 1.0 2.0
.28 .55 1.06 2.06
112 110 106 103
.04 .03 .06 .04
.27 .53 1.02 2.04
.04 .06 .05 .05
108 106 103 102
Journal of Dairy Science Vol. 62, No. 9, 1979
1392
BATRA ET AL.
TABLE 2. Progesterone concentration (ng/ml) in blood plasma and milk of n0npregnant buffalo,
TABLE 3. Progesterone concentration (ng/ml) in blood plasma and milk of pregnant buffalo.
Day of estrous cycle
Day of pregnancy
0a 1 2 3 4 5 7 9 11 13 15 17 18 19 3 --2 1 0
Blood plasma Mean SE .06 .08 .11 .29 .43 .51 1.4 2.2 2.9 3.8 3.7 3.0 2.4 1.8 .62 .42 .30 .10
.03 .07 .04 .15 .11 .14 .27 .64 .79 1.8 1.7 1.7 1.2 1.2 .16 .09 .08 .07
Milk Mean .38 .98 1.6 2.7 3.2 4.4 7.1 13.3 14.5 18.0 18.5 17.5 15.3 13.6 4.4 1.8 .53 .41
SE .12 .15 .14 .24 .31 .52 1.2 .71 1.4 1.5 1.4 .88 1.9 1.7 .13 .34 .13 .12
aDay 0 = Day of insemination.
in milk is due to t r a n s f e r o f p r o g e s t e r o n e f r o m b l o o d to milk or its possible s y n t h e s i s b y m a m m a r y tissue. Heap et al. (8) suggested p r o g e s t e r o n e in c o w s ' milk was a t t r i b u t e d to its diffusion against c o n c e n t r a t i o n g r a d i e n t f r o m b l o o d and c o n c l u d e d t h a t p r o g e s t e r o n e measured in milk was higher, p r o b a b l y as a result o f t h e lipid solubility o f t h e s t e r o i d . However, t h e r e is e v i d e n c e for synthesis o f p r o g e s t e r o n e in m a m m a r y tissue o f goat f r o m t h e infusion o f [3 H] p r e g n a n o l o n e (12) w h i c h indicates t h a t t h e m a m m a r y tissue has e n z y m e s to s y n t h e s i z e p r o g e s t e r o n e . P o p e et al. (11) o b s e r v e d average p r o g e s t e r o n e .86 n g / m l for w h o l e milk and .14 n g / m l for fat free milk. Similarly G i n t h e r et al. (5) f o u n d changes in fat c o n c e n t r a t i o n were closely parallel to p r o g e s t e r o n e c o n c e n t r a t i o n w h e n samples w e r e collected at d i f f e r e n t t i m e s o f t h e day. Thus, it appears t h a t higher milk p r o g e s t e r o n e in c o m p a r i s o n with cows m a y be i n f l u e n c e d b y t h e higher p e r c e n t a g e o f fat in b u f f a l o milk. It generally is agreed t h a t c o n c e n t r a t i o n s o f p r o g e s t e r o n e in b l o o d and milk provide estim a t e s o f luteal f u n c t i o n during t h e r e p r o d u c t i v e cycle. The m i d c y c l e rise o f p r o g e s t e r i n e in plasma and milk appears to result f r o m luteiniJournal of Dairy Science Vol. 62, No. 9, 1979
0a 1 2 3 4 5 7 9 11 13 15 17 18 19 20 21 22 23 24 25 29 33 37 4o
Blood plasma
Milk
Mean
SE
Mean
SE
.08 .07 .18 .34 .46 .57 1.02 2.2 3.0 3.3 2.9 3.7 3.0 3.4 4.0 3.3 3.1 3.4 3.5 4.1 3.9 3.0 3.4 3.2
.03 .01 .06 .09 .08 .10 .09 .98 1.0 .73 .81 .76 .58 .94 .79 .76 .82 1.1 .99 .73 .74 .67 .95 .88
.54 1.7 2.5 3.5 4.1 5.5 9.6 13.3 17.2 20.2 17.3 19.8 21.2 22.2 20.4 21.9 22.8 22.2 20.6 24.4 23.9 20.1 24.7 22.8
.09 .24 .29 .26 .27 .65 1.7 1.7 1.7 1.2 1.9 1.1 1.9 2.1 1.2 1.7 .93 .81 .81 .79 .68 1.8 1.6 .50
aDay 0 = Day of insemination.
zation after o v u l a t i o n and s u b s e q u e n t progest e r o n e secretion b y t h e c o r p u s l u t e u m . The m e a n results f r o m Tables 2 and 3 i n d i c a t e a d i f f e r e n c e in p r o g e s t e r o n e c o n c e n t r a t i o n bet w e e n day 20 t o 25, suggesting t h a t milk p r o g e s t e r o n e m a y provide a m o r e reliable t e s t for early p r e g n a n c y diagnosis in buffalo as in c o w s (11). ACKNOWLEDGMENTS We th~mk D. S u n d a r e s a n , Director, National Dairy Research Institute, for s h o w i n g keen i n t e r e s t in this s t u d y and providing necessary facilities. We also are i n d e b t e d t o B.J.A. Furr for t h e g e n e r o u s gift o f p r o g e s t e r o n e a n t i s e r u m used in assay o f p r o g e s t e r o n e . REFERENCES 1 Arora, R. C., N. K. Bachlaus, A. Prasad, and R. S. Pandey. 1979. Plasma progesterone level and early pregnancy diagnosis in buffaloes heifers. Ind.
BLOOD AND MILK PROGESTERONE
J. Exp. Biol. 17:124. 2 Bachlaus, N. K., R. C. Arora, A. Prasad, and R. S. Pandey. 1979. Plasma level o f gonadal h o r m o n e s in cycling buffalo heifers. Ind. J. Exp. Biol. (In press). 3 Darling, J.A.B., R. W. Killey, A. tt. Laing, and R. A. Harkners. 1972. The isolation and identification of progesterone obtained from cow's milk during pregnancy. J. Endocrinol. 54: 347. 4 Ginther, O. J., L. C. Nuti, B. C. Wentworth, and W. J. Tyler. 1974. Progesterone concentration in milk and blood during pregnancy in cows. Proc. Soc. Exp. Biol. Med. 146: 354. 5 Ginther, O. J., L. C. Nuti, M. C. Garcia, B. C. Wentworth, and W. J. Tyler. 1976. Factors affecting progesterone concentration in cow's milk and dairy products. J. Anita. Sci. 42:155. 6 Gunzler, O., L. Korndorfer, H. Lohoff, R. Hamburger, and B. Hoffman. 1975. Practical experience in the determination of progesterone in milk as an indicator of fertility of cows. Tieraztliche Umschaw. 30;III. 7 Heap, R. B., M. Gwyn, J. A. Laing, and D. E.
8
9
10
11
12
1393
Wahers. 1973. Pregnancy diagnosis in cows: Changes in milk progesterone concentration measured during estrous cycle, pregnancy measured by rapid radioimmunoassay. J. Agr. Res. 81:151. Heap, R. B., A. Henville, and J. L. Linzell. 1975. Metabolic clearance rate, production rate and m a m m a r y uptake and metabolism of progesterone in cows. J. Endocrinol. 66:239. Hoffman, B., and R. Hamburger. 1973. Progesterone in milk: Determination by m e a n s of R[A: relationship between CL function and fat concentration. Zuchthygiene 8:154. Laingh, J. A., and R. B. Heap. 1971. The concentration of progesterone in the milk of cow during reproductive cycle. Brit. Vet. J. 127:XIX. Pope, G. S., I. Majzlik, P.J.H. Nail, and J. D. Leaver. 1976. Use of progesterone concentration in plasma and milk in the diagnosis of pregnancy in domestic cattle. Brit. Vet. J. 132:497. Slotin, C. A., R. B. Heap, J. M. Christiansen, and J. A. Linzell. 1970. Synthesis of progesterone by m a m m a r y gland of goat. Nature (London) 225:385.
Journal of Dairy Science Vol. 62, No. 9, 1979
