A recently neutered male dog may potentially impregnate a receptive female for as long as one month after surgery. Sperm is produced in the testicles then mixes with seminal fluid in the prostate. It is possible for those sperm to survive for as long as a month after the testes, which replenish the supply, are removed.
Can a male dog still impregnate after being neutered?
Neutered dogs can technically impregnate a female dog up to six weeks after their neutering procedure due to dormant sperm. However, after a male dog loses its testicular sacks, it will no longer produce sperm, and therefore will be unable to sire future litters.