Reaction profile

The FDA adverse-event record for decreased number of spermatozoa

Name: Decreased number of spermatozoa - FDA Animal Adverse Reaction
Creator: PlainBreed
License: https://open.fda.gov/license/

33 FDA reports name decreased number of spermatozoa, a lower-volume reaction in the CVM extract (VeDDRA 2129). Plate stamps and neighbourhood peers follow.

#1936 of 2,481
by report volume (all reactions): 33
reports citing this reaction: 6.1%
death-coded share: Dog
most-affected species

Compiled by PlainBreed

Verify with FDA CVM →

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Decreased number of spermatozoa has 33 reports now versus 33 in that prior snapshot: 0 the same number of (0.0%).

Report change: +0
Death-coded reports: +0
Death-coded share: +0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Decreased number of spermatozoa changes

FDA AER · VeDDRA plate

Code 2129 VOL-TRACE

VOL-TRACE · DEATH-PAR · LOWER-Q · PHOTO-FINISH · SPECIES-DOG · DRUG-LEAD · DESK-WIDE · BOOK-FULL

VOL-TRACE 33 reports
DEATH-PAR 6.1%
LOWER-Q #1936/2481
PHOTO-FINISH Abnormal dexamethason…
SPECIES-DOG Dog · 27
DRUG-LEAD Fluralaner Chew T… · 13
DESK-WIDE 20 breeds
BOOK-FULL 8/8 fields

Nearest volume peer: Abnormal dexamethasone suppression test (±0 reports)

Instrument codes from this reaction’s FDA CVM adverse-event extract: volume band, death-coded share, corpus rank, photo-finish peer, lead species, lead drug, breed desk, and book completeness. Not a clinical diagnosis.

Lower-volume neighbourhood around Decreased number of spermatozoa

Lower-third volume poles plus nearest peers, not a full reaction corpus board reprint.

FDA AER report volume · neighbourhood around Decreased number of spermatozoa

Decreased number of spermatozoa: low death-coded share in the FDA AER plate

Signature read: 2 death-coded reports is a thin tail count for Decreased number of spermatozoa in the CVM extract. Report volume is lower-third scale: 33 named reports in the openFDA extract. Death-coded share is lower-third: 2 of 33 reports (6.1% of named reports). Nearest volume peer: Abnormal dexamethasone suppression test (±0 reports). Lead species Dog (27). Lead co-reported drug Fluralaner Chew Tablets (13).

Read these counts as reporting volume, not risk: per our methodology, Lead co-reported drug Fluralaner Chew Tablets appears in filings alongside this reaction; that is association, not causation. Browse the full reactions index or the about page for how PlainBreed frames FDA CVM extracts.

Species Most Affected

Dog 27

Cattle 3

Horse 2

Goat 1

Breeds Most Affected

Retriever - Labrador 7

Bulldog - French 4

Dog (unknown) 2

Terrier - Scottish 2

Samoyed 2

Quarter Horse 2

Terrier - Airedale 1

Crossbred Bovine/Cattle 1

Siberian Husky 1

Terrier - Irish Soft-coated Wheaten 1

Associated Drugs

Fluralaner Chew Tablets 13

Oclacitinib Maleate 4

Milbemycin Oxime + Spinosad 3

Spinosad 2

Afoxolaner 2

Melengestrol Acetate 2

Ivermectin 1

Afoxolaner 136 Mg Chewable Tablets 1

Levothyroxine 1

Da2Ppv+L*4 (Orig S-P Us) Lv+Kb 1

Rabies In Hhh Adj Pfizer Kv 1

Tulathromycin 1

Clodronate Disodium 1

Sarolaner 1

Gonadotropin Releasing Factor (Gnrf) - Diphtheria Toxoid Conjugate 1

Grapiprant 1

Milbemycin Oxime + Praziquantel 1

What to do with this reaction

Read how death-coded share differs from a mortality rate before drawing conclusions. Understanding adverse events
Browse the full reaction directory to compare report counts across reaction types. All reactions

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Decreased number of spermatozoa (#1936 of 2,481 by report volume); death-coded 6.1%. PlainBreed reaction plate · death-coded report count stamp 2 · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →