Changes in serum progesterone patterns during the short luteal cycles initiated after calving and relationship to conception in buffalo-cows

By

Noseir,W.M.B.

Faculty of Veterinary Medicine, Alexandria University, Edfina, Behaira, Egypt

Abstract:

Serum progesterone patterns were assessed in 10 parturient buffalo-cows during the early postpartum period (27-55 days) preceding and succeeding 1st estrus after calving, and their relation to conception. Blood samples were collected from all cows twice weekly for 4 weeks. Estrus was observed in all cows twice daily (late evening and at dawn), and were considered to be in estrus when they stood to be mounted by other cows. A fertile buffalo-bull was left free with cows for natural service. 20% of cows had no estrus cycles. Two (20%) cows showed the first postpartum estrus at day 37 postpartum. 60% of cows (n=6) exhibited 2 heats with interestrus interval ranging between 10 and 11 days indicating occurrence of short luteal periods. 60% of cows had a transient increase in progesterone 3-4 days before the 2nd postpartum estrus. All estrus cows were bred at 1st and 2nd heat, and 60% conceived at the latter estrus. All cows that had a transient increase in progesterone before estrus became pregnant. 40% of cows had no transient progesterone increase before estrus. It could be concluded that the transient increase in progesterone before the 2nd postpartum estrus, increases conception rate and reduces calving-conception interval.

Introduction:

To maintain an optimum 365 days calving interval, cows must reinitiate estrus cycles and conceive by 85 days postpartum (Morrow, 1980). The long postpartum anestrum or days open (> 100 days) results in prolonged calving interval. Many reports have postulated presence of high incidence of prolonged postpartum anestrum (> 4-10 months) in parturient buffalo-heifers and cows (Ref). Werth et.al. (1996) showed that when initiation of the 1st postpartum estrus after calving was preceded by a transient increase in progesterone result in successful breeding. Many authors believed that the development of a short-lived corpus luteum followed by estrus may be necessary for resumption of estrus cycles of typical duration after calving (Odde, et.al., 1980; Romirez-Godinez, et.al., 1981; and Pratt, et.al., 1982). Anderson and Day (1998) concluded that feeding Melengestrol acetate and injection of progesterone during early postpartum period are capable of inducing fertile estrus after calving in cows. Therefore, the influence of transient increase in progesterone and/or presence of short luteal phase on resumption of the 1st postpartum manifested estrus and relationship to conception in buffalo-cows has not been evaluated. The aim of this study is to access the changes in serum progesterone patterns during early postpartum period preceding and succeeding 1st estrus after calving and their relation to conception when breeding occurred at this estrus.

Materials and Methods:

Serum progesterone patterns associated with the initiation of the first manifested estrus after calving were assessed in 10 parturient buffalo-cows (3 primiparous and 7 pleuriparous buffalo-cows). Age range varied between 3-6 years. All cows were in early postpartum period between 27 and 55 days (4 weeks) post calving. Parturitions were between December and March. All cows gave a normal births with normal live calves. Calves were allowed for free suckling program with their mothers. Milk production varied between 3-5 kg/day. Feeding depended mainly on barseem and/or hay, together with mineral supplement. Blood samples were collected by jugular venipuncture twice weekly for 4 weeks starting form day 27 to day 55 postpartum. Serum was separated and stored at -20 c until analyzed for progesterone assay using RIA kits (Diagnostic Products Corporation, USA).

All buffalo-cows were subjected to thorough estrus observation twice daily (late evening and dawn) by well-trained observers. Cows were considered to be in estrus when they stood to be mounted by other cows. A fertile previously tested buffalo-bull was left free with parturient cows for natural service. Pregnancy diagnosis was carried out rectally, 60 days post service.

 

 

Table [1]: Serum progesterone patterns and incidence of estrus in parturient buffalo-cows

Days postpartum

Serum progesterone

(ng/ml)

Cows in estrus

No.

%

27

0.11

--

--

30

0.65

--

--

34

0.89

--

--

37

0.71

2

20

41

0.97

2

20

44

0.99

3

30

48

1.20

2

20

51

1.03

3

30

55

1.03

3

30

 

 

Table [2]: The incidence of postpartum short luteal cycles in buffalo-cows

No. of cows

Cows having short cycles

Interestrus interval (days)

Pregnancy rate

1 cycle

2 cycles

Non

No.

%

No.

%

No.

%

No.

%

10

2

20

6

60

2

20

10-11

6

60

Mean serum progesterone concentration (ng/ml)

1.01 0.67

0.62 0.48

1.35 0.64

 

 

 

 

 

 

Table [3]: The incidence of transient increase in progesterone previous to estrus in parturient buffalo-cows

No. of cows

Cows showed transient progesterone increase

Level of transient progesterone increase (ng/ml)

Onset of the increase (days postpartum)

Days of increase before estrus

No.

%

10

6

60

1.27-1.40

44-55

3-4

 

 

 

 

Fig.[1]: Mean serum progesterone concentration in parturient buffalo-cows (n=6) with 2 short luteal cycles

 

Results and Discussion:

Serum progesterone concentrations during 27 to 55 days postpartum, are presented in table [1]. The concentration varies between 0.11 ng/ml at day 27 postpartum, to 1.03 ng/ml at day 55. Two (20%) out of 10 cows showed the first postpartum estrus at day 37 postpartum. 60% of cows (n=6) exhibited 2 heats with interestrus interval ranging between 10 and 11 days (table, 2 & Fig. 1) indicating occurrence of short luteal periods. 60% of cows had a transit increase in progesterone (1.27-1.40 ng/ml) 3-4 days before estrus (table, 3). All estrus cows were bred at 1st and 2nd heat (after short interestrus interval) and 60% conceived at the latter estrus. All cows that had a transient increase in progesterone before estrus became pregnant, this transient increase in progesterone was first shown at 44-55 days postpartum (table, 3). 40% of cows had no transient progesterone increase before estrus.

The source of the transient increase in progesterone is possibly due to the presence of short-lived corpus luteum or luteinized ovarian follicle. Similar postulates were reported by Donaldson et.al. (1970), Corah et.al. (1979) and Werth et.al. (1996). Yelich et.al. (1997) suggested presence of a persistent dominant luteinized follicle during early postpartum period after calving. Anderson and Day (1998) concluded that administration of progesterone during early postpartum period induced acute increase in progesterone before resumption of the first postpartum fertile estrus. The transient increase in progesterone that occurred before 1st estrus after calving and its relation to conception may possibly have a role in preparation of the reproductive tract of buffalo-cows for pregnancy. Similar findings were reported by Werth et.al. (1996). Kinder et.al. (1995) found similar increase in progesterone preceding pubertal estrus of heifers and hypothesized that this increase serve for providing a more desirable uterine environment that made conception positive as a result of mating at the pubertal estrus.

It is possible to say that this transient increase in progesterone prior to 1st postpartum fertile service increases conception rate and in turn reduces the calving-conception interval.

References:

Anderson, L.H., and Day, M.L. (1998): Development of progestin-based estrus synchronization program: 1. Reproductive response of cows fed melengestrol acetate for 20 days with an injection of progesterone. J. Anim. Sci., 76(5): 1267.

Corach, L.R., Quealy, A.P., Dunn, T.G., and Kaltenbach (1974): Prepartum and postpartum levels of progesterone and estradiol in beef heifers fed two levels of energy. J. Anim. Sci., 39: 380.

Donaldson, L.E., Bassett, J.M., and Thorburn, G.D. (1970): Peripheral plasma progesterone concentration of cows during puberty and the effects of under nutrition or exogenous oxytocin on progesterone concentration. J. Endocrinol. 48: 599.

Kesler, D.J., Faulkner, D.B., Shirley, R.B., Dyson, T.S., Ireland, F.A., and Ott, R.S. (1996): Effect of interval from melengestrol acetate to prostaglandin F2 alpha on timed and synchronized pregnancy rates of beef heifers and cows. J. Anim. Sci., 74(12): 2885.

Kinder, J.E., Bergfeld, E.G.M., Wehrman, M.E., Peters, K.E., and Kojima, F.K. (1995): Endocrine basis of puberty in heifers and ewes. Reproduction in Domestic Ruminants III. J. Reprod. Fert. Suppl. 49, 393.

Morrow, D.A. (1980): Current Therapy in Theriogenology. W.B. Saunders Company, London.

Odde, K.G., Ward, H.S., Kiracofe, G.H., McKee, R.M., and Kittok, R.J. (1980): Short estrus cycles and associated serum progesterone levels in beef cows. Theriogenology, 14, 102.

Patterson, D.J., Hall, J.B., Bradley, N.W., Schillo, K.K., Woods, B.L., and Kearnan, J.M. (1995): Improved synchrony, conception rate and fecundity in postpartum suckled beef cows fed melengestrol acetate prior to PGF2a . J. Anim. Sci., 73(4): 954.

Pratt, B.R., Berardinelli, J.G., Stevens, L.P., and Inskeep, E.K. (1982): Induced corpora lutea in the postpartum beef cow. I. Comparison of GnRH and HCG and effects of progesterone and estrogen. J. Anim. Sci., 54: 822.

Romirez-Godinez, J.A., Kiracofe, G.H., McKee, R.M., Schalles, R.R., and Kittok, R.J. (1981): Reducing the incidence of short luteal cycles in beef cows with Norgestomet. Theriogenology, 15: 613.

Troxel, T.R., Cruz, L.C., Ott, R.S., and Kesler, D.J. (1993): Norgestomet and GnRH enhance corpus luteum function and fertility of postpartum suckled beef cows. J. Anim. Sci., 71: 2579.

Werth, L.A., Whittier, J.C., Azzam, S.M., Deutscher, G.H. and Kinder, J.E. (1996): Relationship between circulating progesterone and conception at first postpartum estrus in young primiparous beef cows. J. Anim. Sci., 74: 616.

Yelich, J.V., Geisert, R.D., Schmitt, R.A., Morgan, G.L., and McCann, J.P. (1997): Persistence of the dominant follicle during melengestrol acetate administration and its regression by estrogen treatment in beef cattle. J. Anim. Sci., 75(3): 745.