+ Positive Mitzvah
Redeem the first born male donkey with a lamb
“The first issue of a donkey you will redeem with a lamb” Shmos 34:20 and give the lamb to the Kohen.
As it says “Every first issue of the womb …. shall be Yours.” Bemidbar 18: 15
Kohanim and Leivim are exempt from this.
If no lamb is available to redeem it, you may redeem for its monetary value and give the money to the Kohen.
If you have a firstling donkey worth 10 selaim (silver coins) you can redeem it with a lamb worth a dinar (a smaller silver coin)
Kohen and Levi are exempt from this.
This is applicable in all places at all times for men and women.