Rob Knox University of Illinois

Publish Date: April 17, 2012

Replacement gilts are essential for maintaining the productivity of the sow breeding herd. Loss of sows from the breeding herd will result from failure to breed, to become pregnant, poor productivity, and structural problems with feet and legs. Producers must plan for current herd specific replacement rates that may average 50%. Managing females to meet replacement needs requires planning for the correct numbers of fertile, mature replacement gilts to breed at the same time as weaned sow groups.

Publish Date: April 17, 2012

Evaluation of boar semen for measures of fertility is an important component to success with artificial insemination (AI). While measures of semen fertility are not highly related to fertility outcomes such as farrowing rate and litter size, use of poor quality semen with poor motility and increased abnormalities is associated with reduced fertility. As a result, the essentials for semen quality includes the basics for overall assessment of the ejaculate and the more specific measures for sperm cell concentration, motility, and percentage of normal sperm cells. It is these measures that are used to determine the number of fertile sperm cells that go into a dose of semen.

Publish Date: June 3, 2006

Sows that fail to establish and maintain pregnancy fail to cover costs associated with their daily maintenance and housing. Pregnancy diagnosis can help to: 1) minimize costs associated with nonproductive days (NPDs), 2) maintain correct number of sows for farrowing crates, 3) identify open females for rebreeding or culling, 4) prevent unintended culling of pregnant sows, 5) identify the timing and extent of reproductive failure, and 6) help predict future pig flow [(1)].

Publish Date: June 3, 2006

Non-pregnant, non-lactating females decrease the reproductive efficiency of swine operations. They generate production costs and occupy space in breeding and gestation facilities, yet they do not participate actively in the production of piglets. As a result, producers invest time and money with essentially no opportunity for return each day that these females remain in the herd.

Publish Date: April 17, 2012

A foreign animal disease is one that does not occur in the United States and needs to be identified with the help of your veterinarian as quickly as possible.

Publish Date: April 19, 2011

Productive sow days are those days when a sow or gilt is either pregnant or lactating. Therefore, a non-productive day (NPD) is any day that a sow, or a gilt once entered into the breeding herd, is neither pregnant nor nursing a litter. The number of NPD is calculated as 365 days – ([gestation days + lactation days] x litters/sow/yr). The primary significance of NPD is that they reduce the number of possible productive days and, therefore, they limit the potential number of litters per year. Assuming maximum sow inventory, limiting the number of litters produced will adversely affect the efficiency of facility utilization. The economic impact of fewer litters will depend on the value of the finished product. The number of NPD influences the ideal sow inventory since with high NPD, more sows will be needed to maintain consistent weaned pig output. If there are excessive NPD (e.g. 85 days), then there are only 280 remaining productive sow days left in the year. Further, if gestation days and lactation days are combined (e.g., 114 + 21 days = 135 days), then the maximum number of litters possible per sow is 2.07 (280 days/135 days). If there are fewer NPD (e.g. 35 days), then there will be 330 productive sow days in the year, and the potential number of litters is 2.44 (330 days/135 days). In each of these scenarios, if the number of pigs weaned equaled 10 pigs, then the effect of the 50 extra NPD between the two scenarios (85 days– 35 days) would result in 3.7 fewer pigs produced each year for each sow (24.4 – 20.7 pigs/sow/year). Put another way, each NPD is worth 0.074 pigs (3.7 pigs/50 days), or more if weaned litter sizes are larger than 10 pigs. However, the true significance of this will depend on whether pork production is profitable or not.

Publish Date: November 12, 2010

Gilt litters can represent as much as 22% of all litters farrowed on a commercial sow farm. Therefore, improvements in gilt productivity will impact the overall reproductive performance of the entire sow herd. Prior to entering the breeding phase, gilts will need to be appropriately managed in a gilt development program that ensures proper growth and body composition, health, and pubertal maturation. The establishment of a management program to effectively stimulate puberty attainment from a smaller pool of replacement gilts is economically beneficial to a sow farm. Effective management of gilts improves the utilization of floor space, labor and flow of service-eligible gilts within the gilt facility. The single most important factor to stimulate early puberty in gilts is boar exposure. The Swine Research and Technology Center at the University of Alberta has designed an area in the gilt development unit called the BEAR (Boar Exposure Area). A schematic drawing of the BEAR is indicated in Figure 1.

Publish Date: November 9, 2010

Hygiene is defined as the science of the establishment and maintenance of health, or the conditions or practices as of cleanliness conducive to health (Merriam-Webster Collegiate Dictionary: www.m-w.com). Providing a clean, disease free environment for the boars will enhance sperm production and prevent disease spread to the sow units it serves. Bacterial contamination of extended boar semen can originate from the ejaculate itself as well as from the environment. While contamination of the ejaculate from the boar is considered normal, it is not desirable and may reduce fertility in sows (Althouse, et. al., 2000; Rillo, et. al., 1998). Indications of bacterial contamination of extended boar semen range from sperm cell agglutination and decreased storage life to reduced fertility and vaginal discharges in mated sows (Althouse, et. al., 1998). In extreme cases with high levels of contamination, endometritis may occur in mated sows, which could result in culling and even sow death (Payne et al., 2008). Find out more about hygiene and sanitation in the board stud in this Factsheet.

Publish Date: April 9, 2010

By definition, anestrus is a condition in swine during which females do not exhibit estrous cycles. During anestrus, the ovaries are relatively inactive and neither large follicles (ovarian structures that contain an ovum or egg, and that secrete large quantities of estrogen; Figure 1) or functional corpora lutea (ovarian structures that secrete progesterone; Figure 2) are present. Anestrus usually results from insufficient secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamic area of the brain. In cycling gilts and sows, GnRH travels by blood to the anterior pituitary gland, a pea-sized organ located near the base of the brain, where it causes secretion of the gonadotropins, luteinizing hormone (LH) and folliclestimulating hormone (FSH). The LH and FSH in turn, stimulate growth of ovarian follicles, ovulation and in the case of LH, normal function of corpora lutea.