Changes to standard animal weights could affect Pa. producers


HARRISBURG, Pa. — The Pennsylvania Department of Agriculture is reminding livestock producers to review changes made to standard animal weights that take effect in 2019.

These new weights could reclassify some livestock farms as Concentrated Animal Operations (CAOs) or Concentrated Animal Feeding Operations (CAFOs), requiring those farms to adopt new levels of compliance with nutrient management laws.

Nutrient Management Act

Pennsylvania passed Act 38, the Nutrient Management Act in 1993, but Pennsylvania’s Nutrient Management Program (NMP) went into effect in 1997, said Frank Schneider, director of the nutrient and odor management programs at the Pennsylvania Department of Agriculture.

The act states that concentrated animal operations will be required to develop and maintain a nutrient management plan.

Pennsylvania’s NMP regulations include a list of standard animal weights used to calculate whether a livestock operation qualifies as a CAO. The weights are periodically adjusted to reflect trends in contemporary production agriculture.

“We have a history of making changes as the industry changes,” said Schneider. “The industry wants a leaner pig (today) and dairy cow weights have increased.”

All species have either increased or decreased weight standards or made grouping changes, he added.

Pa Animal Weights
Source: Pennsylvania Department of Agriculture

Revised weights

The revised weights, approved in May 2017, take effect on Oct. 1, 2019.

“We are giving almost three years to come into compliance with these new regulations,” said Schneider.

Farmers have the option to use other average animal weights instead of the standard weights if there is sufficient documentation to support their use.

Schneider added that factors have also been taken into consideration if livestock is not kept on a yearly basis, such as hogs and broilers.


CAOs are operations that have more than 2,000 pounds of animal weight (Animal Equivalent Units or AEUs) per acre of ground available for manure application.

See also: NRCS, Animal Feeding Operations

CAFOs are operations that have greater than 1,000 AEUs, or CAOs with greater than 300 AEUs, or an operation that meets a specific head count as defined by the Environmental Protection Agency, regardless of the amount of acres available to spread manure.

“If you have over 2,000 pounds (of animal weight) per acre suitable for manure application, then you probably have more manure than you have land — you need to get a nutrient management plan,” said Schneider.

Operations that become newly classified as CAOs or CAFOs due to the new standard animal weights must have their nutrient management plan approved before Oct. 1, 2019.

Current operations classified as CAOs or CAFOs must amend their nutrient management plans with the new standard animal weights within the three-year lifespan of their nutrient management plan.

“Right now, we have roughly 1,000 CAOs (in Pennsylvania). We would expect that we would get an increase,” said Schneider, who added they have not done a farm analysis to know the exact number of producers this would affect.

Get the details

Specific details for Pennsylvania livestock producers regarding these changes is available at county conservation districts or with private consultants, and at the Nutrient Management Program (Act 38) website; search either “standard animal weights” or “agronomy facts 54.”


The Ohio Department of Agriculture has a similar type of manure and nutrient production estimates based on different sizes and species, Ohio Department of Agriculture Communications Director Mark Bruce said in an email.  

“However, in Ohio, the vast majority (estimated 95 percent) of permits use actual data from the facility or a similar type of facility instead of manure and nutrient production values.”

“Right now, the department doesn’t foresee making changes,” Bruce said.


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