Changes in the economics of swine production, and occasionally family and personal changes in the lives of producers, may require that they evaluate their swine enterprise as a component of their livelihood. This evaluation process is not always straightforward and simple. Often it cannot be based solely on economic considerations because emotions, lifestyle, and family ties may be involved.
Whatever decisions are rendered, the ultimate objective of this process is to enhance the producer's personal welfare and to increase profits from the swine production enterprise.
Factors to Consider:
One step in evaluating your swine enterprise is to describe its current status. The following list of descriptive categories can be used to evaluate the current status of a swine production enterprise. There may be other considerations in addition to those listed below.
Four Basic Options: Which Suits You?
Four basic options for swine production enterprises are described below. Characteristics of producers and swine operations that may fit each option are included.
Who to Contact for Further Assistance
The North Carolina Cooperative Extension Service has a center in each North Carolina county. For further assistance, contact your local extension agent in your county North Carolina Cooperative Extension Service Center. In addition to their own expertise, extension agents can contact a variety of specialists and use other resources to respond to your request.
Currently genotypes that produce leaner carcasses are being selected and utilized in commercial pork production. These leaner genotypes are typically longer, leaner and have larger loin muscle areas; however, they also can contain as much as 50% less intramuscular fat, have a higher shear force meat (tougher) and are paler in color. In addition, research has shown that dietary protein content does have a significant impact on carcass composition. If the pig has the genetic potential, feeding high level of protein in the early growing phase(s) can increase carcass leanness.
Researchers K.F. Goerl, S.J. Eilert, R.W. Mandigo, H.Y. Chen and P.S. Miller, at the University of Nebraska, recently reported research results (J. Anim. Sci. 73:3621) from a trial that evaluated the effects of genetic line and crude protein on carcass characteristics. Two genotypes were evaluated: a low lean growth potential line (GP) that has been selected for only reproductive traits for 20 years and a leaner Hampshire (HAMP) line. Treatments (10, 13, 16, 19, 22 and 25% crude protein) were randomly assigned across pens of each genotype. The gilts were fed the assigned diets from 60 to 230 lbs.
The results of the project presented in Table 1 indicated that the HAMP gilts had larger loins and less backfat than the GP gilts. Backfat decreased linearly with increased crude protein and the response of loin area to crude protein was quadratic.
The longissimus muscle of the GP line had greater water-holding capacity than the HAMP line, suggesting a decreased meat quality. Cooking yields of chops from the GP line were greater than cooking yields of chops from the HAMP line. This is another indication of the greater water-holding capacity of the GP line as compared to the HAMP line. No differences in cooking yield were observed in response to the protein treatments.
The shear values indicated a more tender meat from the HAMP line than the GP line, which is not in agreement with previous research. Tenderness was also shown to decrease with increasing levels of dietary crude protein, but had the greatest impact in the 10% crude protein diet, which was a deficiency.
Ham yields of the HAMP line were greater than those of the GP line. Ham lean yields also increased with increasing levels of dietary crude protein. No significant differences were reported for the additional traits of moisture, fat, protein, ash or pH values between the two populations.
This study characterized lean tissue composition, color, tenderness, and water-holding capacity as affected by protein level and two genetic lines. However, feeding only one dietary crude protein level during the grow-finish period is not the most economical nutrition program and staged diets may have an affect on carcass composition and meat quality characteristics. Gilts selected for increased lean deposition exhibited greater protein accretion, lower shear force, and lower water-holding capacity than gilts that received no selection for carcass leanness. However, pork from leaner genetic lines was more tender, likely due to increased protein turnover at the time of slaughter. Dietary crude protein level dramatically altered composition and changed tenderness, especially when deficiencies in dietary crude protein occurred. To improve the quality and consistency of pork products through genetics and nutrition more research will be required.
|Genetic Population||Dietary Crude Protein Level(%)|
|Carcass backfat, in.||1.12||1.63||P<.01||1.46||1.47||1.43||1.25||1.31||1.33||linear|
|Carcass loin muscle area, sq. in.||5.32||4.00||P<.01||3.71||4.71||5.05||4.64||4.88||4.98||quadratic|
|Warner Bratzler peak force||30.78||35.01||P<.01||29.19||32.19||33.09||35.38||35.83||31.69||quadratic|
|Ham lean yield %||56.26||51.97||P<.01||50.56||52.33||54.34||55.44||55.85||56.16||linear|
|Cook yield %||71.02||74.28||P<.01||71.89||73.64||72.69||72.86||71.69||73.16||NS|
If a sow is bred three times in two days, which mating contributed the most number of pigs to the litter when she farrows? This question has always been important, but it takes on new significance with the use of combination matings (natural followed by A.I.). If there is a difference with mating time, then the genetic merit of the sires used for both natural service and for artificial insemination needs to be taken into account.
Dr. Billy Flowers, reproductive physiologist at North Carolina State University, recently released data from an experiment which he designed and conducted to answer this specific question, i.e., what is the influence of timing of matings during estrus on the paternity of individual pigs in the litter. He used 40 multiparous sows and 17 mature boars in an experiment, where estrus was checked twice daily and each female was bred three times at 12 hour intervals beginning at the first detected estrus. Thirty-five of the sows received combination matings with a single different boar used for each mating. Matings were arranged so that every possible combination of matings from boars occurred an equal number of times. Blood samples were obtained from all piglets in the experimental litters ten days after farrowing. These blood samples were submitted to DNA extraction and analysis to establish piglet parentage.
The proportion of piglets sired by the first, second and third boar in the breeding sequence is presented in Table 1. In those litters with piglets from two different sires, the second and third boar used in the breeding sequence sired more (p <.05) piglets than the first boar (boar 1, 23.7 ± 2.3; boar 2, 45.0 ± 3.4; boar 3, 31.3 ± 4.5%). Also, in litters containing piglets from all three sires, the second and third boars in the breeding sequence sired more (p < .05) piglets than the first boar, even though the distribution tended to be more uniform than in litters with two sires. Overall, 25.7 ± 2.3, 41.5 ± 3.7 and 32.8 ± 4.5% were sired by the first, second and third boars in the sequence, respectively.
According to Dr. Flowers, the results demonstrate that the majority of the pigs in a litter are the result of a single mating. Further, this mating usually is not the first one the sow receives during estrus. In this experiment, approximately 75% of the pigs farrowed were the product of the A.I. matings. Consequentlx, Dr. Flowers emphasizes that the genetic merit of the A.I. sires used in combination matings is very important.
|Variable||First Sire||Second Sire||Third Sire|
|Litters with 2 sires||23.7 ± 2.3x||45.0 ± 3.4y||31.3 ± 4.5z|
|Litters with 3 sires||27.7 ± 3.5x||37.0 ± 4.0y||35.3 ± 4.7y|
|All litters||25.7 ± 3.3x||41.5 ± 3.7y||32.8 ± 4.5y|
|x,y,z Means with different superscripts within rows are different (p < .05).|