http://protectmustangs.org/?p=8749

PZP — The Pesticide

Porcine zona pellucida (PZP aka ZonaStat-H or Native PZP) is an EPA-registered pesticide derived from the ovaries of slaughtered pigs. PZP is approved for use on wild horses “in areas where they have become a nuisance ….” [20]

Some persons argue that, because PZP does not kill the mare, it is not really a “pesticide.” Actually, PZP does kill. As will be documented in this report, its use is associated with stillborn foals. In the long term, PZP will weaken a herd immunologically, which could swiftly lead to its extinction. So, yes, PZP is a real pesticide.

PZP — an Anti-Vaccine

While touted as a “vaccine,” PZP is actually a perversion of what a true vaccine is supposed to be. Instead of preventing disease, PZP causes disease — auto-immune disease. Thus, PZP is an anti-vaccine.

PZP’s True Mode-of-Action

So how does PZP really work? PZP tricks the immune system into waging war on the ovaries. In a meta-analysis of ZP-type contraceptives, Kaur & Prabha (2014) reported that the infertility brought on by such products is ” … a consequence of ovarian dystrophy rather than inhibition of sperm-oocyte interaction.” Thus, PZP’s antibodies “work” not by blocking sperm attachment but by destroying the ovaries.

PZP → Endocrine Disruptor → Elevated Testosterone → Masculinizing Effects

Recall that PZP has endocrine-disrupting effects that result in lowered estrogen. Per the observed masculine behavior of treated mares,

Recent Stillbirths Correlated with PZP

There is recent evidence confirming Nettles’ finding of a correlation between PZP treatments and subsequent stillbirths.

Autoimmune Oophoritis and Risk of Other Autoimmune Diseases

A study by Varras et al. disclosed that, in humans, autoimmune oophoritis carries the risk of the patient developing other autoimmune diseases. [23]

Prolonged Delay in Recovery of Fertility

The same longitudinal study by Ransom et al. found that, after suspension of PZP, there was a delay lasting 411.3 days (1.13 years) per each year-of-treatment before mares recovered their fertility. What this means is that it takes that long, on average, for the ovaries to heal, to clear out all those cysts, and to regain some degree of normal hormonal function.