The attached poster is the second in a series of three pictorial displays developed to help pork producers more effectively screen replacement gilt candidates before placing them in their breeding herds.
In addition to poor conformation and structural soundness (see Poster 1, Jan. 15, 2005, National Hog Farmer), feet and leg disorders or injuries can adversely affect gilt soundness. Whether purchasing replacement gilts or utilizing your own internal multiplication program, the poster inserted here provides examples of feet and leg problems that should be avoided when selecting replacement gilts.
Some feet and leg injuries or disorders, if left untreated or ignored, can adversely affect a sow's lifetime performance in the breeding herd. Identifying and culling replacement gilts that have one or more of the conditions illustrated in the poster may be one of the keys to lowering breeding herd replacement and/or mortality rates.
Injury and Disorder Causes
The feet and leg disorders shown on the poster can have genetic, health and environmental causes.
Traits that are genetically influenced include toe size, swollen joints (caused by structural and/or conformational defects like post-legged animals) and others. These traits have been shown to be heritable and can be improved through genetic selection. Therefore, it is important to remember that traits that contribute to structural soundness (or unsoundness) in a parent will also have an impact on their offspring.
For example, if animals with structural deficiencies (uneven toe size, swollen joints, etc.) are retained for breeding purposes, we would expect a significant number of their offspring to have the condition, too. Unsound animals do not perform as well as their more sound counterparts.
Many environmental factors also influence feet and leg disorders and injuries. For example, pitted concrete surfaces can result in more cracked hooves; sharp edges on new slats can cause more abrasions of the pads of the foot and result in abscesses.
Similarly, many penning materials are attached to the floor with the bolt sticking up, where an animal could step on it or injure other parts of the legs or body. Cutting excessively long bolts flush with the nuts could help reduce these injuries. Equipment with sharp or rough edges can result in similar injuries. These types of issues can be easily corrected by adhering to a routine maintenance schedule.
Dealing with Swollen Joints
Many health problems can cause pigs to have swollen joints. Both the degree and duration of joint swelling can vary. When the animals recover from the disease, the swelling can disappear. However, long-term damage may have occurred.
Gilts with swollen joints should be avoided when selecting breeding herd replacements. The swollen joints are indicative of either a disease or structural problem.
Animals with swollen joints, uneven toes and cracked hooves are also more likely to pose problems during transportation and lairage at harvest facilities. They may require additional trimming in the slaughter plant.
The organizers of this series of three posters, which present guidelines for more effective replacement gilt screening, had to visit only three operations to find the vast array of structural, feet and leg and reproductive trait imperfections presented. This reinforces how common many of these conditions are, and that no operation is free of all of these challenges.
It should be noted that not all animals have perfect structural and reproductive soundness. Any selection program must evaluate and prioritize the importance of numerous traits. Compromises must often be made.
Ask yourself: Should a gilt with a minor structural defect be culled at the expense of leaving a farrowing crate empty? Probably not. But recognize the consequences of retaining these suspect animals in the breeding herd.
Try to anticipate how a defect will affect an individual's productivity in the farrowing crate. Will the defect be passed on to their offspring? How will it impact their performance?
The third in this series of posters, focusing on reproductive trait soundness (underlines and external genitalia), will be inserted in the March 15, 2005 edition of National Hog Farmer.
To Order More Posters
This series of posters was produced through the cooperative efforts of Pork Checkoff, National Swine Registry, National Hog Farmer and Iowa State University Swine Extension.
The complete set of three posters will be available free to U.S. producers and agricultural educators after March 15. Non-producer and foreign poster orders are available for 50¢ each. Contact Pork Checkoff at 800-456-PORK or view the Pork Checkoff catalogue at www.porkboard.org.