Reproduction

Publish Date: June 15, 2022

Porcine reproductive and respiratory syndrome virus (PRRSv) is one of the most costly and difficult to manage diseases within the swine industry. In breeding herds, it causes reproductive losses such as substantially increased incidence of abortions and mummies, and infertility. Downstream, in pigs of all ages, it causes pneumonia with clinical signs such as thumping and coughing, and impacts production by reducing growth and increased mortality. The control, elimination and prevention of PRRS is an integral part of modern swine management, especially in breeding herds.

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 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: 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: 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.

Publish Date: July 31, 2007

Detection of estrus or standing heat is one of the most critical components of a successful swine breeding program. The widespread adoption of artificial insemination (AI) in the swine industry has shifted the responsibility of detecting estrus from boar to breeding technician. Accurate and consistent detection of estrus is necessary to ensure insemination occurs near the time of ovulation and to identify open females. Errors in detection of estrus reduce reproductive performance and increase herd non-productive days. Since accurate heat checks are so vital, all individuals involved must know the typical signs that females approaching estrus in their herd exhibit and how to best use a boar to stimulate females to express estrus. Reviewed: April 2021

Publish Date: June 3, 2006

Daily care and management of sires in an artificial insemination (AI) center can have a large influence on semen quality and sperm output. A typical boar produces from 1100 to 1200 doses of semen per year (22 doses/wk x 52 wks) and therefore, semen quality of a single sire influences a large number of matings and services per year. A rule of thumb is that each female inventoried will require about six doses of semen on an annual basis (2.2 L/S/Y x 2.2 matings per service x 80% FR x 10% semen wastage (unused doses) . Therefore, each sire inventoried in the boar stud could meet the semen needs for 150 to 200 females inventoried on the breeding farm. The following are some important points to consider for optimal management of sires maintained in a commercial AI center.

Publish Date: June 3, 2006

Herd boars influence the swine breeding program in two important ways. One, they provide a source of genetic improvement and two, they have an effect on farrowing rate and litter size. In addition, replacement boars can be a potential source for the introduction of disease into a herd. The following guidelines provide information to help make decisions when purchasing new boars, acclimating them to their new environment and managing them for productive service as mature boars. This article is based on PIH-1 (12/93).

Publish Date: June 3, 2006

Boars generally show an interest in mounting stationary objects. Therefore, an estrous female is not required when collecting semen to be used for artificial insemination (AI). Adjustable height mounting dummies can easily be made or purchased from a supplier of AI equipment. Basic requirements for a good mounting dummy include appropriate height for mounting and straddling of the boar’s forequarters, structural stability, and durability. Good footing around the dummy is essential to aid the boar in mounting and thrusting, and in the semen collection process. Rubber matting material with openings is a popular choice because it provides for good footing, resiliency to constant use, non-absorbency, and ease of cleaning between uses.

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)].