J. HAWAIIAN PACIFIC AGRIC. 13: (2006) A Survey of Breeding and Selection Practices among U.S. Pork Producers

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1 J. HAWAIIAN PACIFIC AGRIC. 13: (2006) A Survey of Breeding and Selection Practices among U.S. Pork Producers Erik R. Cleveland, College of Agriculture, Forestry and Natural Resource Management, University of Hawai i at Hilo, 200 W. Kawili St., Hilo, Hawaii Alton M. Okinaka, College of Arts & Sciences, University of Hawai i at Hilo, 200 W. Kawili St., Hilo, Hawaii Gilbert R. Hollis, Department of Animal Sciences, University of Illinois, 204 Animal Sciences Center, 1207 West Gregory Drive, Urbana, Illinois ABSTRACT In 1988 and 1989, commercial pork producers from across the U. S. were surveyed concerning their use of various breeding and selection practices. Questionnaires from 1613 pork producers were included in this study. The majority of the producers were using at least some home-raised replacement gilts. Rotational crossbreeding was the most popular crossing system used by these pork producers. Among these producers, the breeds most frequently used to produce crossbred sows were Yorkshire, Duroc, and Hampshire. The most popular sire breeds for market hog production were the Duroc, Hampshire, and Yorkshire breeds. Among these producers, the health status and health program were the most important criteria used in selecting breeding stock suppliers. A variety of boar selection criteria were probably used by the producers surveyed. However, growth rate, feet & legs, and feed conversion seemed to be the traits that received the most emphasis in the minds of these producers. Our results suggest that the majority of the producers surveyed preferred to buy performance tested boars. When performance tested boars were available, the majority of the producers surveyed indicated that they used performance records in making selection decisions. The vast majority of the producers surveyed indicated that some form of performance testing program should be emphasized to insure that genetic improvement occurred in the swine industry. Also, the vast majority of the producers felt that there was at least some need to verify the use of health, testing and selection practices among breeding stock suppliers. KEYWORDS: Swine, Survey, Breeds, Crossbreeding, Selection INTRODUCTION Animal geneticists have developed crossbreeding, performance testing, and genetic evaluation programs to assist pork producers. However, it is not known what proportion of the U.S. pork producers make use of the recommended breeding and selection practices. Because of this, it was decided to survey U. S. pork producers to assess their use of various breeding and selection practices. Another purpose of the survey was to assess the breeding stock needs of commercial pork producers. This survey was designed to provide information about U.S. pork producers at a given point in time. MATERIALS AND METHODS In the fall of 1987 and winter of 1988, commercial pork producers in five states were surveyed concerning the use of various breeding practices (Cleveland 1989a,b,c,d). After conducting the preliminary five-state survey, it was decided to modify the questionnaire for a more detailed survey among U. S. pork producers. In the fall of 1988, university extension swine specialists, county extension agents, and state pork producer association representatives were contacted to solicit their assistance in conducting this nationwide survey. For every state, at least one producer representative (university swine specialist, J. HAWAIIAN PACIFIC AGRIC. (2006) Page 43

2 county extension agent, or state pork producer association representative) was contacted so that their state would be represented in the survey. These individuals were asked to distribute the questionnaires to pork producers in their state. In some states the producer representatives mailed the questionnaires to their pork producers. In other states the producer representatives distributed the questionnaires to pork producers attending swine meetings. Questionnaires were collected in 1988 and 1989 from every region of the U.S. A total of 1613 questionnaires were processed using a survey analysis program (MicroCase, 1987). The response rate for this survey was not calculated since it was not possible to determine how many pork producers received the questionnaires. RESULTS AND DISCUSSION Survey results are summarized in Tables 1 through 7. Overall results as well as results by geographical region are presented. For the analysis, a response of a given percentage represents the proportion of respondents selecting that answer. For several questions, more than one answer could be selected per question. Description of the Herds For the 1613 producers surveyed, 27.7% had herds of 1 to 50 sows, 30.0% had herds of 51 to 100 sows, 32.0% had herds of 101 to 300 sows, and 10.2% had herds of over 300 sows (Table 1). In the Northeast, South and West, over 40% of the producers had herds of 1 to 50 sows. For the Midwest, only 22.9% of the producers had herds of 1 to 50 sows. The Midwest appeared to have a lower percentage of small swine operations than the other regions. Less than 15% of those surveyed were using purchased gilts as their only source of replacement females (Table 1). Most producers were using at least some home-raised gilts as replacement females (Table 1). These results are not surprising since purchased gilts are usually more expensive and often pose a greater health risk than home-raised females. Crossbreeding Systems Crossbreeding Systems This survey examined the use of various crossbreeding systems (rotational, terminal, and rota-terminal). With the rotational crossbreeding system the producer rotates the use of various breeds of sires while saving replacement gilts from within the herd. For the terminal cross, terminal sires are mated to crossbred females with all resulting pigs being sent to market. The rota-terminal crossbreeding system makes use of both the rotational system and the terminal cross. With this system, the rotation is used in part of the herd as a way to produce replacement females for the entire operation. For the rest of the herd, terminal sires are used with all resulting pigs being sent to market. Overall, 48.5% of the producers were using the rotational crossbreeding system (Table 1). For every region the rotational crossbreeding program was the most popular crossing system among pork producers (Table 1). The popularity of the rotational system may be related to several factors. One advantage of the rotational crossbreeding system is that all replacement females are produced from within the herd. With rotational crossbreeding, producers can use either the rotation in time or the spatial rotation (Bourdan, 2000). With the rotation in time a second advantage is that only one breed of sire would be needed at a given point in time which would simplify the management of the system (Bourdan, 2000). Overall 22.7% of the producers surveyed were using the terminal cross and 19.3% were using the rota-terminal crossbreeding system. Page 44 J. HAWAIIAN PACIFIC AGRIC. (2006)

3 Breeds Found in the Pedigree of Crossbred Sows Pork producers were asked to list breeds found in the ancestry of their crossbred sows (Table 2). For this question, more than one breed could be selected as an answer. Crossbred sows will have two or more breeds in their ancestry. Of the producers surveyed, 63.5% had some sows with Yorkshire breeding. The percentage of producers with Yorkshire crossbred sows varied from a low of 60.1% in the Midwest to a high of 79.3% in the South. The Yorkshire breed was by far the most popular breed in every region. The popularity of this breed may be related to its reputation of having excellent maternal performance (Briggs, 1983). Yorkshire crossbred sows have ranked very well in regards to maternal traits (Johnson, 1980). Overall 48.1% and 46.5% of the producers had some sows with Hampshire and Duroc breeding, respectively. The Hampshire and Duroc breeds were the second and third most frequently found breeds in the ancestry of crossbred sows. The percentage of producers with Hampshire breeding in their sows varied from a low of 42.3% (for the Northeast) to a high of 51.1% (for the West). For Durocs the percentage varied from a low of 37.2% (for the Northeast and South) to a high of 48.9% (for the West). Several other breeds were used by a sizable proportion of respondents in producing crossbred sows (Table 2). Of the producers surveyed, 33%, 25.8% and 20% had some crossbred sows with Landrace, Large White and Chester White breeding, respectively. The moderate use of Landrace, Large White and Chester White crossbred sows may be due to their reputation of having excellent maternal performance (Briggs, 1983; Zeller, 1964). In crossbreeding studies Landrace crossbred sows have ranked very well in regards to maternal traits (Johnson, 1980). Breeds of Sire for Market Hogs Producers were asked to list which breeds of boars were used to sire their market hogs (Table 3). For this question, more than one breed could be selected as an answer since some herds use more than one breed of sire at a given time. Duroc, Hampshire and Yorkshire boars were used by 37.3%, 35.5% and 33.3% of the producers, respectively. According to Briggs (1983), these three breeds have a good reputation for use in commercial pork production. Johnson (1980) reported that Duroc crossbred pigs excel in growth rate while Hampshire crossbred pigs excel in leanness. Apparently, many producers recognize the relative value of Duroc and Hampshire boars as sires of market hog. The use of Duroc boars varied from a low of 0% in the Northeast to a high of 51.8% in the West. For the Hampshire breed, the proportions varied from 31.6% in the Northeast to 49.6% in the West. The use of Yorkshire boars varied from 28.4% in the Midwest to 58.6% in the South. This variation in the use of these breeds among regions may be related to several factors including the availability of breeding stock. Overall, hybrid, Duroc-Hampshire, Chester White, and Large White boars were used by 24.3%, 17.4%, 11.7% and 10.7% of the respondents, respectively. With the development and promotion of commercial breeding companies, it is not surprising that some producers were using hybrid or Duroc-Hampshire crossbred boars at that point in time. Source of Boars Pork producers were asked to list the sources of their herd sires (Table 4). For this question, producers could select more than one answer since they might have purchased boars from more than one J. HAWAIIAN PACIFIC AGRIC. (2006) Page 45

4 source. For example, a producer might have purchased some boars from a breeder selling only purebreds as well as purchasing some boars from a breeder selling both purebred and crossbred boars. Of the producers surveyed, 47.1% were obtaining some of their boars from breeders selling only purebred stock. Overall 41.5% of the producers were buying some boars from breeders selling a combination of purebred and crossbred animals. Both of these breeder categories can fit into the category of the private seedstock producer. Before the development of commercial breeding companies, private seedstock producers were undoubtedly the main source of outside breeding stock for most commercial producers. For the producers surveyed, 23.5% were using some boars from breeding companies while 20.2% were using some home-raised boars. Criteria used in Selecting Breeding Stock Suppliers Producers were asked to rate the degree of importance for various criteria that might be used in selecting breeding stock suppliers (Table 5). For this question the following rating scale was used: 1 = not important, 2 = slightly important, 3 = somewhat important, 4 = important and 5 = very important. The health status and health program of the breeder s herd received the highest scores 4.7. These results suggest that pork producers feel that these health factors are important criteria for selecting breeding stock suppliers. Furthermore, these results are not surprising since the purchase of unhealthy breeding stock can dramatically affect the health status of the producer s herd and their net income. Apparently, commercial producers seek out breeding stock producers with healthy animals. Criteria that might be used to judge the genetic merit of breeding stock herds received scores varying from 3.1 for test station ranking, 3.7 for farm testing program, 3.9 for selection program, and 4.2 for reputation. These factors are important to a degree but buying healthy breeding stock is apparently more important in the mind of these commercial producers. Other criteria had scores of 2.7 for location, 3.0 for the supply of animals, 3.3 for prices, and 4.0 for the breeds & lines available. Apparently, commercial producers considered the selection program, reputation, and breeds & lines available as important factors in selecting seedstock suppliers. Criteria used in Selecting Boars Criteria used in Selecting Boars In the survey producers were asked to rate the degree of importance of various traits that might be used in selecting boars (Table 6). For this question, the following rating scale was used: 1 = not important, 2 = slightly important, 3 = somewhat important, 4 = important and 5 = very important. According to the respondents, all the traits were at least somewhat important. Growth rate, feet & legs, and feed conversion received the highest mean scores of 4.6, 4.5 and 4.4, respectively. Traits receiving scores of 4.0 to 4.1 included backfat, loineye, litter size, conformation, and visual reproductive traits. Index score and litter weight received scores of 3.5 and 3.6, respectively. These results might be expected due to the economic importance of various traits and the ease of which different traits are measured. Feet and leg structure is very important in the mind of commercial producers. This trait can be easily evaluated and it is an important trait since it affects the animal s ability to move around. Growth rate is an economically important trait since fast growing hogs reach market weights in fewer days. Growth rate is relatively easy to measure if a scale is available. Feed efficiency is an economically important trait since efficient hogs require less feed per pound of gain. It takes special facilities and extra work to measure feed efficiency. During the time of this survey, it is likely that most private breeding stock producers were not measuring feed efficiency for selection Page 46 J. HAWAIIAN PACIFIC AGRIC. (2006)

5 purposes. It is likely that most of the surveyed producers were not able to actually select boars based on feed conversion ratios unless they were buying boars from central test stations. At the time of the survey, central test stations were probably supplying boars to only a small percentage of the U. S. pork producers. Feed efficiency was probably an important trait in the mind of pork producers even if they were not able to use it as a selection criterion. Role of Performance Testing Producers were asked whether they were using performance tested boars (Tables 4). Of the producers surveyed, 45.4% were using performance tested boars. Overall 31% of the producers were using untested boars but had a preference for tested animals. Only 23.6% of the producers were using untested boars and had no preference for tested individuals. These results suggest that the majority of the pork producers preferred to buy performance tested boars. Pork producers were also asked whether they used performance records in selection when performance tested boars were available (Table 7). When tested boars were available, 82% of the producers indicated that they used performance records in making selection decisions. These results suggest that the majority of these commercial producers recognized the value of performance records in making wise selection decisions. Producers were asked whether central testing, farm testing, or hog shows should be emphasized to insure that genetic improvement occurred in the swine industry (Table 7). The vast majority of the producers felt that some form of a performance testing program (either central testing or farm testing) should be emphasized. Less than 5% of the producers felt that hog shows should be emphasized. Finally, the survey tried to assess the producers attitudes toward verifying health, testing, and selection practices among breeding stock suppliers (Table 7). Overall 98% of the producers felt there was at least some need to verify the use of health, testing, and selection practices among breeding stock suppliers. Based on these results, the breed associations should consider developing programs that verified the use of health, testing, and selection practices among breeding stock herds. The use of such a program would serve as an incentive for breeding stock producers to improve the genetic merit and health status of their herds. The publication of program results would provide useful information that could be used by pork producers in selecting breeding stock suppliers. CONCLUSIONS Among those surveyed during the years of 1988 and 1989, the majority of the pork producers were using at least some home-raised replacement gilts. Rotational crossbreeding was the most popular crossing system used by these pork producers. The breeds most frequently used to produce crossbred sows among these producers were Yorkshire, Duroc, and Hampshire. The most popular breeds of sires for market hog production were the Duroc, Hampshire, and Yorkshire breeds. Among these producers, the health status and health program were the most important criteria used in selecting breeding stock suppliers. A variety of boar selection criteria were probably used by the surveyed producers. However, growth rate, feet & legs, and feed conversion seemed to be the traits that received the most emphasis in the minds of these producers. Our results suggest that the majority of the producers surveyed preferred to buy performance tested boars. When performance tested boars were available, the majority of the surveyed producers indicated that they used performance records in making selection decisions. The vast majority of the surveyed producers indicated that that some form of performance testing program should be emphasized J. HAWAIIAN PACIFIC AGRIC. (2006) Page 47

6 to insure that genetic improvement occurred in the swine industry. Also, the vast majority of the producers felt that there was at least some need to verify the use of health, testing and selection practices among breeding stock suppliers. The results reported in this study apply to the years of 1988 and It is possible that the attitudes of U.S. pork producers and the use of various swine breeding practices have changed since Our study provided some historical survey data that might serve as a resource for pork producers and as a guide for future surveys on swine breeding and selection practices. ACKNOWLEDGMENTS The authors would like to thank the university extension swine specialists, county extension agents, and state pork producer association representatives that collected the data for this survey. Without their involvement, it would have been difficult to conduct this survey. Thanks are also due to the pork producers who took time to answer this questionnaire. Last but not least, thanks are due to the students who were involved in helping with this study. LITERATURE CITED Bourdon, R.M Understanding animal breeding. Prentice Hall. Upper Saddle River, NJ. Briggs, H.M International pig breed encyclopedia. Elanco, Indianapolis, IN. Cleveland, E.R. 1989a. Selection and crossbreeding practices used in commercial pork production in five states. J. Anim. Sci. 67(Suppl. 1):611. Cleveland, E.R. 1989b. The use of crossbreeding and selection practices in the swine industry. I. An analysis among Indiana commercial producers. J. Haw. Pac. Agri. 2: Cleveland, E.R. 1989c. The use of crossbreeding and selection practices in the swine industry. II. An analysis among Missouri and Wisconsin commercial producers. J. Haw. Pac. Agri. 2: Cleveland, E.R. 1989d. The use of crossbreeding and selection practices in the swine industry. III. An analysis among Hawaii commercial producers. J. Haw. Pac. Agri. 2: Johnson, R.K Heterosis and breed effects in swine. North Central Regional Research Publication. No MicroCase MicroCase: User s Guide. Cognitive Development, Inc. Seattle, WA. Zeller, J.H Breeds of swine. Farmers Bulletin No United States Department of Agriculture. Page 48 J. HAWAIIAN PACIFIC AGRIC. (2006)

7 Table 1. Herd statistics of the respondents by region. Item Percentage of respondents Number of sows in the herd Overall Midwest Northeast South West Over Source of replacement gilts Home-raised Purchased Combination Crossbreeding system used Unplanned Rotational Terminal Rota-terminal J. HAWAIIAN PACIFIC AGRIC. (2006) Page 49

8 Table 2. Percentage of respondents by region having various breeds represented in the ancestry of their crossbred sows. Breed or line Percentage of respondents Overall Midwest Northeast South West Berkshire Chester White Duroc Hampshire Landrace Large White Poland Spotted Yorkshire Hybrid Other Page 50 J. HAWAIIAN PACIFIC AGRIC. (2006)

9 Table 3. Percentage of respondents by region having various breeds of boars used to sires market hogs. Breed or line Percentage of respondents Overall Midwest Northeast South West Berkshire Chester White Duroc Hampshire Landrace Large White Poland Spotted Yorkshire Hybrid Other Duroc-Hampshire J. HAWAIIAN PACIFIC AGRIC. (2006) Page 51

10 Table 4. The backgrounds and source of boars for respondents by region. Item Percentage of respondents Producers using Overall Midwest Northeast South West Tested boars Untested boars Untested boars but prefer tested animals Source of boars Home-raised Breeders selling purebred animals Breeders selling purebred & crossbred animals Companies Other sources Table 5. Mean scores for respondents by region for various criteria that might be used in selecting breeding stock suppliers.* Criteria Overall Midwest Northeast South West Selection program Test station ranking Supply of animals Location Price Farm testing program Breeds & lines available Health status Health program Reputation *A given values represents the mean ± standard deviation. A 1 to 5 scale was used in rating the various criteria with 1 = not important, 2 = slightly important, 3 = somewhat important, 4 = important, and 5 = very important. Page 52 J. HAWAIIAN PACIFIC AGRIC. (2006)

11 Table 6. Mean scores for respondents by region for the various criteria that might be used in selecting boars.* Criteria Overall Midwest Northeast South West Backfat Growth rate Feed conversion Loineye Litter size Litter weight Index Conformation Feet & legs Visual reproductive *A given values represents the mean ± standard deviation. A 1 to 5 scale was used in rating the various criteria with 1 = not important, 2 = slightly important, 3 = somewhat important, 4 = important, and 5 = very important. J. HAWAIIAN PACIFIC AGRIC. (2006) Page 53

12 Table 7. An assessment of the attitudes of the respondents by region. Item Percentage of respondents Overall Midwest Northeast South West When tested boars are available, do you use the performance records in selecting among boars within a group? Yes No Which one practice should be given the most attention to insure that genetic improvement occurs in the swine industry? Farm testing Central testing Hog shows Is there a need to verify health, testing, and selection practices used by breeding stock producers? Large need Some need No need Page 54 J. HAWAIIAN PACIFIC AGRIC. (2006)