Ovarian activity and cervical mucus in a one month old calf

Keywords: ovary, Graafian, follicle, estrogen, spinnbarkheit

The reproductive tract of a one month old heifer. The tract appeared to be normal; the hymen already perforate.

Image size: 1813 x 1789 px

Although there were no macroscopically visible follicles in the ovaries, numerous small tertiary (Graafian) follicles were present (see inset).  There was also an accumulation of mucus in the cranial vagina showing spinnbarkheit similar to that seen in cows during estrus. This suggested that the follicles were steroidogenically active.

Note:
Postpartum ovarian weight in heifers increases from birth to about 4 months of age but does not increase much more than that until the onset of puberty. During this time, the rest of the reproductive tract also grows, apparently stimulated by the presence of ovarian steroids. Prepuberal (prepubertal) heifers as young as two weeks of age already show regular waves of FSH secretion preceding regular follicle waves; similar to those seen in adults. In fact, both FSH and LH reach substantial concentrations between birth and about two months of age. After that time, negative feedback from ovarian steroids appears to take effect and by three to four months of age the gonadotropins have been suppressed to baseline concentrations. The reason for this early prepuberal rise in gonadotropins is not known.

References:

N.C. Rawlings, N.C. et al. 2003 Antral follicle growth and endocrine changes in prepubertal cattle, sheep and goats. Anim. Reprod. Sci. 78:259–270

Metestrus 1: Metestral hemorrhage in bedding.

Keywords:  metestrus, bovine, management, cow, estrous, cycle, detection, hemorrhage

Image size:454 x 326px

This is seen in about 50 to 60% of cows and 75 to 85% of heifers.  It is usually seen in the first 48 hours after ovulation but because the vagina may slope downward at its cranial end (especially in older animals) vaginal mucus and metestral hemorrhage may be retained in the vagina for several days, being discharged several days after estrus. If metestrus is suspected, one should look at the rump of the animal and her dung and bedding where there is often evidence of hemorrhage.

Careful observation is warranted because hemorrhage may be difficult to spot:

Image size: 750 x 526 px

Metestrus 2: Metestral hemorrhage on the tail

Keywords:  metestrus, bovine, management, cow, estrous, cycle, detection, hemorrhage

Image size: 1584 x 2816px

This is seen in about 50 to 60% of cows and 75 to 85% of heifers.  It is usually seen in the first 48 hours after ovulation but because the vagina may slope downward at its cranial end (especially in older animals) vaginal mucus and metestral hemorrhage may be retained in the vagina for several days, being discharged several days after estrus. If metestrus is suspected, one should look at the rump of the animal and her dung and bedding where there is often evidence of hemorrhage.

Metestrus 3: Metestral hemorrhage on the tail 

Typical metestral hemorrhage; seen on the tail of a cow.

Image size: 1584 x 2816px

This is seen in about 50 to 60% of cows and 75 to 85% of heifers.  It is usually seen in the first 48 hours after ovulation but because the vagina may slope downward at its cranial end (especially in older animals) vaginal mucus and metestral hemorrhage may be retained in the vagina for several days, being discharged several days after estrus. If metestrus is suspected, one should look at the rump of the animal and her dung and bedding where there is often evidence of hemorrhage.

Metestrus 4. Hemorrhage seen in bedding 

Typical metestral hemorrhage; seen on the bedding of a cow.

This is seen in about 50 to 60% of cows and 75 to 85% of heifers.  It is usually seen in the first 48 hours after ovulation but because the vagina may slope downward at its cranial end (especially in older animals) vaginal mucus and metestral hemorrhage may be retained in the vagina for several days, being discharged several days after estrus. If metestrus is suspected, one should look at the rump of the animal and her dung and bedding where there is often evidence of hemorrhage.

Metestrus 5. Hemorrhage seen in bedding

Keywords:  metestrus, bovine, management, cow, estrous, cycle, detection, hemorrhage

Image size:1164 x 774px

This is seen in about 50 to 60% of cows and 75 to 85% of heifers.  It is usually seen in the first 48 hours after ovulation but because the vagina may slope downward at its cranial end (especially in older animals) vaginal mucus and metestral hemorrhage may be retained in the vagina for several days, being discharged several days after estrus. If metestrus is suspected, one should look at the rump of the animal and her dung and bedding where there is often evidence of hemorrhage.

Metestrus 7. Hemorrhage on the rump of a cow.

Keywords:  metestrus, bovine, management, cow, estrous, cycle, detection, hemorrhage

Image size:1584 x 2816px

Typical metestral hemorrhage; seen on the rump of a cow that was recently in heat. This is seen in about 50 to 60% of cows and 75 to 85% of heifers.  Metestral hemorrhage is usually seen in the first 48 hours after ovulation but because the vagina may slope downward at its cranial end (especially in older animals) vaginal mucus and metestral hemorrhage may be retained in the vagina for several days, being discharged several days after estrus. If metestrus is suspected, one should look at the rump of the animal and her dung and bedding where there is often evidence of hemorrhage.

Cattle are the only domestic animals that show hemorrhage as a result of estrogen withdrawal.