Contrac All-Weather Blox Rodenticide - Questions & Answers

The risk of secondary poisoning with Contrac Blox is very minimal. A mouse only consumes a very small amount of bait at a time and passes it very quickly only keeping a smaller amount in their liver until they succumb to the effects of the bait. A cat would have to actually eat 20-30 mice that have consumed the bait for it to have an effect. In most cases well fed domesticated animals will not actually eat a mouse or a rat that they come across. Instead they will play with it, chew it and then leave it behind.

Contrac Blox is an anti-coagulant which means once the mice eat this product they begin to bleed to death from the inside.  The mice first become sick, and then grow tired and weak and pass in their sleep.  It can take anywhere from a few hours to a few days depending on how much the mice have eaten.  They do not need water for the product to work.

The federal government has decided that certain types of rodenticides should not be sold in the same manner they have been after June 4, 2011.  These regulations were passed to try to prevent over the counter sales of rodenticides to homeowners and minimize secondary poisoning and misuse of rodenticides.  Unfortunately too many people have placed rodenticides in locations they should not be, such as easy to access places that children and pets can easily get to.  Basically all of the smaller quantities of rodent bait that you have been able to purchase over the counter will no longer be available.  You will only be able to purchase bait already inside a rodent station that is a one time use product.  It will come pre-baited in a sealed rodent station.  This will be the general rule for big box stores like Wal-Mart and Home Depot.  For a specialty store like ourselves, Do My Own Pest Control, we will no longer be able to sell certain rodent place packs, liquid rodenticides, or bait blox in smaller quantities than 16 pounds.  This was passed to discourage homeowners from purchasing rodenticides since they have to now purchase them in large quantities.  Most homeowners do not need 16 lbs worth of place packs.  We will be able to continue to sell the current stock that we have of currently labeled product while supplies last.  However, after June 4th, once we sell out of our current stock and start receiving newly manufactured bait, we will no longer be able to sell it in less than 16lb increments.  There will be some baits that we can continue to sell in smaller quantities but they will be very few and only the ones that have a minimal secondary poisoning risk.

Contrac Blox is usually preferred in homes with pets and/or children as there is a readily available antidote in the event of accidental ingestion and because of the reduced risk of secondary poisonings (if one of your dogs were to eat a poisoned mouse). Final Blox is used when a fast clean out is needed as it will kill the rodents a bit faster than the Contrac Blox. Final Blox does have a higher risk of secondary poisoning. We recommend that you use tamper resistant bait stations that will help stop accidental poisonings of non-target animals no matter which bait you select.

Contrac bait will not have any effect on insects. We recommend that you sprinkle a slug bait around the exterior of the bait stations to control the slugs before they enter the stations. We have several slug baits available including Hi Yield Snail and Slug Bait, Sluggo Plus Snail & Slug Killer and MotherEarth Granular Scatter Bait.

Each blox of Contrac is 28 grams which equal 2800mg. If your pet ate an actual blox, I wouldn't take the chance of figuring it out because the minimum amount could be lethal. It would be best to take your pet to the vet and have him/her take a look and/or administer the antidote which is Vitamin K1.

Yes. There is not a rodenticide on the market that stops a decomposing rodent from smelling after they die. There are a lot of "old wives tales" that suggest that there are rodenticides that will make a rodent exit the building after they eat the bait, leave in search of water or dry up immediately after death and leave no stench behind. Unfortunately, none of this is true. If a rodent dies, it will smell as it decomposes and the rodent will die wherever it succumbs to the poison which is likely to be is an inaccessible area where the rodent has been nesting. We recommend using glue boards, snap traps or multi-catch mouse traps indoors, so you will know exactly where the mouse has died and can remove it with ease.

Each 18 lb. pail contains about 288 blox

Contrac Blox should be used within about 1 year of the purchase date. The active ingredient within the product would most likely stay effective long after 1 year but the food ingredients or the attractants will start to degrade and will no longer be attractive to rodents. Just opening and closing the lid of the storage container would not cause the product to lose its efficacy, but storing the product without a lid could cause it to mold or otherwise degrade. Contrac Blox and Contrac Place paks are essentially the same product just in different shapes and packaging. Contrac Place Paks are very useful for treating mice that love to tear open and gnaw through packaging and the pellets are small enough for them to hold and consume, but the product would eliminate both rats or mice. Contrac Blox work well for both rats and mice by providing them with a large gnawing surface.

Do you know if they ate the Contrac blox that you put down the burrows?  Did the rodents die from those blocks and never went in the stations? Typically, if none of the blocks are eaten then there is a food competition issue.  If there is other food accessible that is more attractive to the rodents then they will eat the other food first.  This could be pet food, bird seed, food in a garden, etc...  Do any of these situations exist?  Also, placement of the bait stations are critical.  Were the station placed along the foundation or along edges with holes against the wall?

You can use any of our rodenticides such as Contrac Blox to eliminate pack rats. You should place the Contrac Blox inside of tamper resistant stations to secure the blox so that the rats can not carry them away to unsecured locations. Be sure to place plenty of stations out as this type of rat can be territorial and will stop other rats from visiting certain stations.

While we are not the manufacturer of the Contrac blox we do carry another product that is for use in areas where secondary poisoning of predatory birds are an issue.  Terad3 rodenticide is usually used in areas where secondary poisoning is a concern because it has a reduced risk of secondary poisoning.

It is a poison so if it is injested, it is likely to harm whatever is injesting it.

Below is a few helpful hints for baiting Mice.

• Always use fresh bait. Rodents will avoid old, moldy, or insect-ridden baits.

• When baiting for mice, a good measure for distance between placements is 8 to 12 feet apart for light to moderate infestations. Heavy or severe infestations may require placements of 4 to 8 feet.
  
  

• As a rule, many bait placements containing smaller amounts of bait are more effective in mouse control than a few placements containing a lot of bait.
  
  

• For heavy infestations, use the maximum number of bait placements indicated by the label.
  
  

• Bait stations should be placed where mice are likely to encounter them during their routine travels, between harborages and food sources.
  
  

• Corners are "hot spots" for bait placements since mice tend to spend a lot of time in darkened corners.
  
  

• Attempt to locate "favorite feeding locations" (indicated by a high concentration of rodent signs-droppings, tracks, odors, shredded paper, etc.) and replace existing food sources with bait stations in these locations.
  
  

• Always use mouse-sized bait stations, not the larger stations designed for rats.
  
  

• Mice often live above or below their food sources, in attics or basements, so bait placements should not be limited to a single level of the infested structure.
  
  

• Mice develop preferences for certain types of foods and baits. If there appears to be bait avoidance, try placing 3 or 4 different bait formulations (pellets, place packs, bait blocks, liquid bait) to see if the mice will prefer one formulation over another.
  
  

• If a bait placement remains unvisited upon inspection, try moving the placement five feet in another direction.

Contrac Blox is a single feed rodenticide. Single feed means a rodent can consume a lethal dose of Bromadiolone in 1 feeding therefore resulting in death within 1-5 days. The number of rodents that 1 block will treat is undeterminable. Place 3 to 16 Contrac Blox (usually at intervals of 15 to 30 feet) per placement. Maintain an uninterrupted supply of fresh bait for at least 10 days or until signs of rat activity cease. Replace contaminated or spoiled bait immediately. Collect and dispose of all dead animals and leftover bait properly. To prevent reinfestation, limit sources of rodent food, water, and harborage as much as possible. If reinfestation does occur, repeat treatment. Where a continuous source of infestation is present, establish permanent bait stations and replenish as needed. 

We recommend that you call your veterinarian immediately. We have linked the Contrac Blox product label and the Contrac Blox MSDS for you in our answer so that you may print them out and provide them to your vet.

After a rodent consumes a lethal dose of the Contrac Blox it can take about a week for the rodent to die. You should keep replacing the bait until you do not have any more activity at the bait station because you could have more rodents than you realize, as is often the case.

Horses and rats are both mammals and the bait will have the same effect on both of them. Of course a horse weighs a lot more so it would need to consume more of the bait to receive a lethal dose. We are not sure if horses would be attracted to the bait because it has not been tested for horses. Bait should never be tossed into spaces because of a rats tendency to move it around. In the future you should use piano wire to string the bait onto and then nail the wire down so the rats can not take off with the bait (for spaces that inaccessible to non-target animals and children only). For places that are accessible to children and non-target animals the bait should be placed in tamper resistant bait stations which will also prevent the rat from removing the bait.