Introduction

Successful herd reproductive performance depends heavily on the management of the breeding female population. Because a single infertile sow or gilt cannot influence overall reproductive to the extent that an infertile boar will, it's not common to overlook the reproductive problems with the breeding female. From a physiological perspective, management considerations in optimizing female reproductive performance include genetics, nutrition, environment, health, stress and of course, breeding. However, reaching and maintaining reproductive performance targets extends beyond these factors to include: Production scheduling, choice of a mating system, good record keeping, breeding barn design and skilled, proven personal. The intent here is to focus not on common mistakes that occur when managing breeding females, but more specifically, the oversights that may occur in the five general areas of sow management that I have noted. Although each management factor listed here could in itself be addressed in much more detail, the following will briefly address a specific oversight in each area that should pertain to all swine farms.

Genetics

Perhaps the most common management mistake related to genetics is in assuming that all females, regardless of genetics, have similar reproductive behaviors. Genetics can influence feed intake, growth, health, longevity (culling rates) and all aspects fertility. The genetic merit of the breeding stock that you choose in your operation should be documented and made available for you. Along with merit, the information provided should include some estimation of key behavior characteristics that indirectly effect reproduction, which is commonly overlooked. Some examples of these behaviors include: 1) Age of puberty for determining when to move gilts, induce estrus (PG600), and breed, 2) estimate of lactation feed intake under optimal conditions and 3) some estimate of estrus length for gilts and sows in establishing insemination strategy. It is important to remember that farm-to-farm differences will exist and therefore validation of characteristics that indirectly affect reproductive performance will improve the management level of breeding females and the consistency of reproductive performance.

Nutrition

Perhaps the most influential nutritional affect on reproduction is the relationships between lactation feed intake and return to estrus interval (Reviewed by Einarsson and Rojkittikhun, 1993). Failure to recognize this relationship will result in increase non-productive sow days and inefficient pig flow through gestation and breeding. Reduced feed intake during lactation generally results in an increase in return to estrus interval. Increasing feeding frequency, avoiding excessive energy intake during gestation, high farrowing room temperatures and water restrictions are key management factors to consider when attempting to optimize lactation feed intakes.

Environment

Environment, social status, and stress have all been shown to interact with reproduction. In principle, any management strategies that can reduced stress and allow for some social interaction with other animals will enhance the well being of animals and consequently, reproductive performance. Importantly, stress prior to, during, and following breeding can result in higher incidences of embryo mortality. One of the most common mistakes in management is a failure to recognize that during breeding and gestation, females are also susceptible to heat stress when temperatures reach and exceed 80 -85°F for short or extended periods of time (Flowers, 1997). Heat stress has its most detrimental effect on reproductive performance during two critical stages of the gestation period, the first 30 days and the last 30 days. Increasing ventilation rates, installing cooling systems such as drip cooling, geothermal cooling or evaporative cooling systems are popular methods in alleviating heat related suppression of lactation feed intake.

Health

Identifying ways to reducing operational costs is generally considered a good managerial characteristic. However, the price for overlooking the complexity of herd health and its reproductive success can be high. Failure to work with a veterinary on herd health maintenance is a common management error. Recognize that a good swine vet should pay for themselves in the sense that disease and heath issues are complex and there are management areas that you should be addressing. You still must be able to recognize and communicate potential health problems, your veterinarian and determine the frequency of veterinary use. Veterinarians are useful resources in evaluating breeding herd records, determining vaccination programming, periodic farm review, and training farm labor (injections, material handling, observations). It is important to remember that the relationship between health and reproduction is crucial, but the next biggest mistake in this area of management assuming that all in reproductive performance are associated with a disease or health status. A drop in reproductive performance or failing to achieve targets can be influence by all of the areas discussed in this paper. Consider all the factors that influence the performance measure that is failing.

Breeding

The three direct areas of female management in the breeding process are heat detection, quality of insemination, and frequency and timing of inseminations. One of the most common mistakes in managing these processes is in assuming that this is required to perform these tasks are easily learned. Dr. Billy Flowers conducted an evaluation of six different technicians' skills, as measured by experience, in 1995. The results from this evaluation showed that herd reproductive performance (as measured by the number of piglets produced from 230 matings) can vary significantly between breeding technicians, irregardless experience. Regardless of how many times a person has either supervised or performed a natural service or artificial insemination, some technicians will not succeed in producing a consistently high number of offspring from these matings. Therefore, careful supervising and evaluation of breeding barn personal, even the experienced technicians, is a must. Obviously, apples must be compared to apples, and therefore each individual technician should have equal opportunities in number of matings at similar times and under similar conditions to be fairly evaluated. Not everyone, regardless of their personality, experience and knowledge, will succeed in this area of reproductive management of females.

The use of AI can allow for a higher degree of quality control than natural service, specifically, semen quality and genetic improvements. AI users however, are totally responsible for fertile semen that is deposited into the uterus, which is unlike natural service where the boar controls these occurrences. Accurately timing multiple inseminations can be difficult and , is the fundamental in the success of AI. Missed timed inseminations leads to lower fertility and many of the problems associated with farrowing rate and litter size can be attributed to poorly timed and performed inseminations. Rozeboom et al., (1997) showed that when the last of multiple inseminations is performed during late estrus, lowered farrowing rates and litter size will occur. A common mistake in many operations is a failure to ensure that female are actually in standing heat while performing what is considered to be the last AI. Direct female-to -male contact (at least nose-to-nose) at every heat check and breeding is a key components in effectively using multiple inseminations. Even though insemination frequency improves reproductive performance, breeding the sow when she's not longer in estrus does not. Become familiar of herd estrual behavior, implement an AI schedule and do not assume that it's correct for each female!

Take-Home Message

Outlined in this proceeding are a few of the oversees in the five major areas of sow reproductive management. The most common mistakes in managing breeding females generally occurs when one becomes too comfortable with normal routines and fails to recognize that in the biological process of reproduction, routine occurs and adjustments must be make to accommodate these changes. Genetics, nutrition, health, environmental factors and to a lessor degree, breeding strategies, all have major influences on the reproductive dynamics, behaviors and reproductive performance of the breeding herd. The reason that very few farms consistently reach and maintain a high level of reproductive performance is because management fails to understand how changes in these management areas described here can impact reproductive process.

Suggested Reading

Einarsson, S. and T. Rojkittikhun. 1993. Effects of nutrition on pregnant and lactating sows. J. Reprod. Fert. (Suppl. 48):229-239.

Flowers, W. L. 1995. Optimizing management of natural and artificial matings in swine. Proc. North Am. Vet. Conf. 9:519-521.

Flowers, W. L. 1997. Artificial Insemination in Swine. In. Current Therapies in Theriogenology. pp.678-683.

Rozeboom K. J., M. H. T. Troedsson, G. C. Shurson, J. D. Hawton, and B. G. Crabo. 1997. Late estrus or metestrus insemination subsequent to estrual inseminations decreases farrowing rate and litter size in swine. J. Anim. Sci. 75:2323-2327.