J. Anim. Sci. 2004. 82:2164-2168
© 2004 American Society of Animal Science
The reproductive performance and factors affecting on-farm application of low-dose intrauterine deposit of semen in sows
K. J. Rozeboom*,1,
D. L. Reicks
and
M. E. Wilson*
* Minitube of America, Inc., Verona, WI 53593 and
and
Swine Vet Center, St. Peter, MN 56082
 |
Abstract
|
|---|
The objective of this experiment was to determine the reproductive performance and factors that affect on-farm application of low-dose intrauterine insemination (IUI) in sows. Four hundred twenty-two sows were used in a simple arrangement of four treatments to determine the effect of spermatozoa per dose (0.5 x 109, 1 x 109, or 4 x 109 IUI, and 4 x 109 with a conventional catheter) on the main effects of conception, litter size, and farrowing rate. Following weaning at approximately 18 d after parturition, estrus detection was performed daily in the presence of a mature boar. At the time of estrus detection, sows were blocked for parity (1, 2, or 3+), weaning-to-estrus interval (WEI; 3, 4, or 5 d), and assigned randomly to be serviced twice with semen from the same boar(s). Treatment services were equally divided among three technicians. Delivery of acceptable numbers of spermatozoa per dose with either device (IUI or conventional) produced similar reproductive performances; however, farrowing rate, total pigs born, and total born alive decreased (P < 0.05) when suboptimal numbers (
1 x 109) of spermatozoa were used with IUI. Treatment interactions with parity were not detected and were removed from the final model. Treatment interactions with WEI on farrowing rate were detected (P < 0.05), and sows with WEI of 3 d had a markedly lower (P < 0.05) farrowing rate than all other treatment groups. The results from this experiment suggest that placement of semen at the beginning of the uterine horn with conventional volumes and spermatozoa numbers produces results similar to placement of semen in the cervical cavity with a conventional AI catheter. Although there is little published evidence of reproductive performances in a commercial setting with suboptimal numbers of spermatozoa, these results suggest that insemination beyond the cervix does not offset effects of suboptimal numbers of spermatozoa.
Key Words: Artificial Insemination • Intrauterine • Sow • Spermatozoa
|
Introduction
|
|---|
Sows and gilts receive 2.4 to 3.0 inseminations (doses) with 3 to 5 billion motile spermatozoa per dose 2.4 times per year. When a single AI occurs within 24 h before ovulation, fertility rates can exceed 91%, making it seem that multiple inseminations are unnecessary and contribute to economic inefficiency in swine reproduction (Soede et al., 2000
). Sperm per dose and doses per mating affect the efficiency of semen utilization because a reduction of sperm per dose would result in more doses produced per boar and a considerable economic savings (Levis et al., 2002). Decreasing the number of doses per mating would mean more available doses for more matings. In both cases, the semen from a boar could be used to service more females. Sows can be surgically inseminated with as few as 10 million sperm without a significant drop in fertility (Rath et al., 1999) and similar results can be achieved nonsurgically with specialized visual insemination equipment (Vazquez et al., 1999). Watson and Behan (2002) obtained similar results with 2 x 109 vs. 3 x 109 spermatozoa per insemination using a commercially available insemination device that deposits semen 10 to 14 cm beyond traditional cervical insemination practices. Using similar procedures, Gall (2002) found farrowing rates and litter sizes were comparable when sows were inseminated with 0.8 x 109 or 3 x 109 spermatozoa. Although low-dose delivery approaches were initially developed to achieve reasonable fertilization rates when using biotechnologies where larger numbers of spermatozoa were not available, increasing the number of semen doses from genetically valuable boars in a traditional AI system may be of considerable importance. Therefore, the objective of this experiment was to evaluate the reproductive factors that affect the success of low-dose commercial application of intrauterine insemination (IUI).
|
Materials and Methods
|
|---|
Animals and Treatments
Four hundred twenty-two sows from a pool of 3,600 multiparous Yorkshire x Landrace sows on a single sow farm were used for this study from July 2001 through December 2001. Gilts were not used because IUI could not be consistently performed with the equipment used (Minitube of America, Verona, WI). Sows were housed in 0.61 x 2.13 m crates in a mechanically ventilated confinement breeding facility and fed a standard corn–soybean meal (14% CP; as-fed basis) gestation diet. All nutrients met or exceeded NRC (1988) recommended levels. A simple arrangement of four treatments was used to determine the effect of spermatozoa number per dose with IUI on the main effects of litter size and farrowing rate. Following weaning, sows were blocked for parity, and wean-to-estrus interval (WEI; 3, 4, or 5 d), and examined for standing estrus daily. After estrus was detected, each sow was randomly assigned to one of the following four treatment groups: 1) IUI with 0.5 x 109 spermatozoa using an IUI catheter (n = 106; Minitube of America); 2) IUI with 1 x 109 spermatozoa (n = 106); 3) IUI with 4 x 109 spermatozoa (n = 106); or 4) conventional cervical deposit (n = 104) using a conventional FoamTip catheter (Minitube of America) with 4 x 109 spermatozoa in approximately 85 mL of semen extender.
Treatment Preparation
Semen was collected alternately but equally as needed from three pools (i.e., Pool A consisted of Boars 1, 2, 3, and 4; Pool B consisted of Boars 5, 6, 7, and 8; and Pool C consisted of Boars 9, 10, 11, and 12) of the same four boars (PIC U.S.A., Franklin KY) with known fertility using the gloved-hand technique and brought to the laboratory for evaluation of spermatozoa concentration with an SDM4 (Minitube of America) and subjective visual motility assessment under a light microscope. To be accepted for breeding, the gross ejaculate motility needed to exceed 80% and gross normal morphology (heads, tails, and droplets) needed to exceed 80%. Each ejaculate was fully diluted with Androhep PLUS semen extender (Minitube of America) to a concentration of 0.047 x 109/mL, and the four ejaculates were mixed. Approximately half the pool was removed and further diluted to either 0.011 or 0.0058 x 109/mL to form doses containing 1 or 0.5 x 109 sperm/85-mL dose of semen. The semen extender contained active gentamicin (350 mg/L of extender) to minimize bacterial growth. All samples were used within 72 h of production or discarded. Prepared doses were cooled to 16°C and transported to the farm, where they were stored in a semen storage unit (Minitube of America) until insemination.
Estrus Detection and Insemination
Sows used for breeding were weaned at 18 ± 5 d after farrowing. Estrus detection was performed daily at 0800 beginning on the third day after weaning. Sows were given nose-to-nose contact with a mature boar in conjunction with backpressure. Those exhibiting a standing reflex to these stimuli were considered to be in estrus. Sows were inseminated 12 h after estrus detection and 24 h later with semen from the same boar(s) by one of three technicians who were rotating with each service. The same technician performed both matings for each service. Females were allowed nose-to-nose contact while they were inseminated using a Minitube FoamTip catheter (conventional AI) or an IUI catheter (Minitube of America). Before insertion, the FoamTips used for both conventional and IUI catheters were lubricated with a nonspermicidal, sterile lubricating jelly (Priority Care, First Priority, Inc., Gilberts, IL). During insemination, backpressure was applied and the insemination fluid was allowed to flow into the uterus by gravity. For IUI treatments, the FoamTip was placed in the cervix in the same manner as with the conventional AI, and the inner tubing was gently pushed through the FoamTip catheter shaft, passed through the cervix, and situated presumably in the uterine lumen or uterine body. Immediately following insemination, an AI quality score (blood presence = yes or no; catheter passage = yes or no) was recorded for each procedure.
Data Collection
At the first insemination, the sow identification, parity, WEI, technician, and semen age were recorded. After each breeding, technicians recorded the incidence of blood on the catheter when it was removed from the sow and any incidences when the catheter could not be passed through the cervix. Conception rates were determined by transcutaneous real-time ultrasound (Real McCoy, E.I. Medical, Loveland, CO), 28 to 35 d after breeding. Farrowing rate was calculated once farrowing or return to estrus had occurred in each female. The total number born (including mummified fetuses) and total number born alive were counted at farrowing.
Statistical Analysis
Analysis of variance using the GLM procedure of SAS (SAS Inst., Inc., Cary, NC) was used to determine the effects of treatment, parity, WEI, and their interactions on the main effects of conception, farrowing rates, and litter sizes. The presence of blood on the catheter and passage of the catheter and their interactions with the main variables on the main effects were initially included as covariates, but later removed because of lack of significance. Bonferroni’s comparison of group means was used to compare variance between group mean differences for conception rate, farrowing rate, and litter size x treatment. All data were analyzed with SAS software.
|
Results and Discussion
|
|---|
During the trial, 422 sows were artificially inseminated. Of these, 318 were serviced using an intrauterine semen delivery device, and 104 sows were serviced with a conventional AI catheter. Of the 636 IUI services performed, 38 (6%) were not completed due to failure of the catheter to pass through the cervix, and 25 (4%) of the IUI services resulted in the presence of blood on the catheter. When either of these events occurred, theses sows were not rebred with a control dose and were not moved into the control group, but rather remained in the treatment to which they were originally assigned. Neither failure to pass the IUI catheter or the presence of blood on the catheter had an effect on the main effects of conception (P = 0.46 and P = 0.24, respectively), farrowing rate (P = 0.75 and P = 0.39, respectively), total born (P = 0.89 and P = 0.08, respectively), or litter size (P = 0.80 and P = 0.07, respectively). A decrease (P < 0.05; Table 1) in farrowing rate occurred in sows bred with lower numbers of spermatozoa per dose using the IUI delivery device. The farrowing rate of sows inseminated with 0.5 x 109 spermatozoa was lower (P < 0.05) than the farrowing rate of sows inseminated with an industry standard number (4 x 109) of spermatozoa using the IUI delivery system. There was, however, no difference between low spermatozoa IUI and the insemination of 4 x 109 spermatozoa with a conventional catheter. In contrast to farrowing rates, total pigs born and total pigs born alive were markedly lower (P < 0.05; Table 2) in the 0.5 x 109 and the 1 x 109 IUI treatments compared with the conventional control mating group. Similar litter sizes were achieved with acceptable spermatozoa numbers in both the conventional catheter and IUI catheter groups.
View this table:
[in this window]
[in a new window]
|
Table 1. The 28-d conception and farrowing rates of sows inseminated with 0.5, 1, or 4 x 109 viable sperm cells with an intrauterine catheter (IUI) or 4 x 109 viable sperm cells using a conventional (Conv) cervical cathetera
|
|
View this table:
[in this window]
[in a new window]
|
Table 2. Total pigs born and born alive from sows inseminated with 0.5, 1, or 4 x 109 viable sperm cells with an intrauterine catheter (IUI) or 4 x 109 viable sperm cells using a conventional (Conv) cervical cathetera
|
|
Treatment interactions with parity were not detected and were therefore removed from the final model. Three technicians with varying levels of reproductive experience were chosen for this study. Technician A was proficient in the application of conventional AI and had more than 5 yr of experience. Technician B was not as proficient with conventional AI, but was very experienced in the use of an IUI catheter, having performed more than 500 IUI treatments. Technician C had no experience using either insemination methodology.
A treatment interaction with WEI on the main effect of farrowing rate was detected. The farrowing rate of sows with a three-dimensional WEI that were bred with suboptimal numbers of spermatozoa was lower (P < 0.05; Table 3) than in all other groups.
View this table:
[in this window]
[in a new window]
|
Table 3. Conception (CR), farrowing rate (FR), total born (TB), and piglets born alive (BA) from sows inseminated with 0.5, 1, or 4 ± 109 viable sperm cells using an intrauterine catheter (IUI) or 4 ± 109 viable sperm cells using a conventional (Conv) catheter following a 3-, 4-, or 5-d weaning-to-estrus intervala
|
|
Although technician experience differed, the effects of technician or interactions thereof were included in the model, and summary data of the results of technician on farrowing rate and litter size are presented in Table 4. However, one should consider that, based on the highly variable results from other investigations with AI and IUI, it is evident that considerable farm-to-farm and technician variation may still exist in a commercial environment with either AI or IUI.
View this table:
[in this window]
[in a new window]
|
Table 4. Influence of technician (n = 3) on farrowing rate (FR), total piglets born/sow farrowing (TB), and total pigs born alive/sow farrowing (BA) from sows inseminated with 0.5, 1, or 4 x 109 viable sperm cells with an intra-uterine catheter (IUI) or 4 x 109 viable sperm cells using a conventional cervical cathetera
|
|
Investigators have shown that fertility rates can be maintained using 2 to 5 billion spermatozoa per dose (Baker et al., 1968; Colenbrander, 1991; Soede et al., 1995a,b). Conditions such as aged spermatozoa, improper semen handling, improper AI technique, and inadequate sanitation can cause inconsistencies in reproductive performance after infrequent insemination (less than 2x) with low numbers of spermatozoa (Baker et al., 1968; Steverink et al., 1997).
The results from the current study suggest that reproductive performance, as measured by farrowing rates and litter sizes, cannot be maintained when suboptimal IUI semen dose concentrations are used. However, the results from the farm in this study may not necessarily reflect similar procedures on other farms. Martinez et al. (2001, 2002) showed similar farrowing rates among sows inseminated with 3 x 109 and those inseminated with a much smaller number of spermatozoa (<1 x 109). In contrast to the results of the current study, the catheter-placement procedure (fiber-optic endoscope) approached the uterine tubule junction, and a much smaller (5 mL) volume of semen was used. It is difficult to predict how this type of system may be applied on a commercial sow farm because specialized skill is required to transverse the uterine body to deposit semen in this location. Nevertheless, Watson and Behan (2002) achieved similar results when decreasing spermatozoa numbers per dose between 2 and 3 x 109 sperm. In their report, delivery of a decreased number of spermatozoa (from 3 to 2 x 109) by IUI produced similar results, whereas a reduction of spermatozoa to 1 x 109 using a conventional delivery mechanism produced significantly lower reproductive performance. In a different study (Roca et al., 2003), further application of this breeding technique (IUI) was shown to also be beneficial for the deposit of frozen-thawed semen. In that report, no differences were detected in either farrowing rates or litter sizes between IUI-delivered frozen-thawed doses containing 1 x 109 sperm, IUI-delivered fresh doses with 0.150 x 109 sperm, or conventionally delivered fresh doses with 6 x 109sperm (Roca et al., 2003). Unfortunately, a repetition of this experiment using only the two IUI treatments was conducted, and the results from the follow-up trial showed a considerable decrease in the farrowing rate with frozen-thawed semen, even though litter size remained comparable. Based on these reports and others (Gall, 2002), it seems possible to use an IUI delivery of suboptimal sperm numbers and still achieve acceptable reproductive performance.
A sufficient population of spermatozoa is presumed to be present in the oviduct within 20 to 30 min after insemination (Hunter, 1990). However, these spermatozoa must first transverse the uterus to reach the apparent security of the utero-tubule junction (UTJ). The uterus seems to serve not only as a transport vehicle for spermatozoa, but also as a defense mechanism, with a local immune system that does not support a sustenance function in maintaining spermatozoa viability (Rozeboom et al., 2000).
According to Weitze et al. (1994), sows can be classified into three categories based on WEI: early, regular, and late. Sows returning early tend to have longer estrous periods than do sows returning later following weaning. Because ovulation generally occurs during the latter third of estrus, the first insemination of sows returning early (i.e., 3 to 4 d) should be delayed by 24 h because they most often have long standing estrus lengths. The consequences of variations in the intervals between insemination and ovulation on fertilization were reviewed by Kemp and Soede (1997). Results from three experiments show that variation in intervals (i.e., more than 24 h) from insemination to ovulation results in partial or no fertilization. It may be suggested that a threshold for a minimum number of spermatozoa in the inseminate was reached in females with short WEI using the IUI catheter. In this case, insemination with 0.5 x 109 spermatozoa may be insufficient to overcome a longer insemination-to-ovulation interval. This is perhaps best exemplified in the current study when suboptimal spermatozoa numbers were used in conjunction with a seemingly increased insemination-to-ovulation interval.
From the present results, there were at least two limitations to using a low-dose insemination (<1 billion spermatozoa) on the farm with IUI: 1) spermatozoa transport is highly inefficient in the pig and seems to require specialized spermatozoa placement equipment (Martinez et al., 2002) to transport the spermatozoa from the uterine body to the UTJ, and 2) optimal insemination timing and technique are consistently required but seldom achieved.
1 Correspondence: 419 Venture Ct. (phone: 800-646-4882; e-mail: krozeboom{at}minitube.com).
Received for publication May 28, 2003.
Accepted for publication March 26, 2004.
|
Literature Cited
|
|---|
Baker, R. D., P. J. Dziuk, and H. W. Norton. 1968. Effect of volume of semen, number of sperm and drugs on transport of sperm in artificially inseminated gilts. J. Animal Sci. 27:88. (Abst.)[Abstract/Free Full Text]
Colenbrander, B. 1991. Commercial use of swine AI worldwide: A roundtable. Reprod. Domest. Anim. 25:184–190.
Gall, T. 2002. Fertlity of intra-uterine vs. intra-cervical insemination of semen in swine. J. Anim. Sci. 80(Suppl 2):46. (Abstr.)
Hunter, R. H. F. 1990. Fertilization of pig eggs in vivo and in vitro. J. Reprod. Fertil. 40(Suppl.):211–226.
Kemp, B., and N. M. Soede. 1997. Consequences of variation in interval from insemination to ovulation on fertilization in pigs. J. Reprod. Fertil. 52(Suppl.):79–89.
Levis, D. G., S. Burroughs, and S. Williams. 2002. Use of intra-uterine insemination of pigs: Pros, cons & economics. Pages 39–62 in Proc. American Assoc. of Swine Vet. Kansas City, MO.
Martinez, E. A., J. M. Vazquez, J. Roca, X. Lucas, M. A. Gil, I. Parrilla, J. L. Vazquez, and B. N. Day. 2001. Minimum number of spermatozoa required for normal fertility after deep intrauterine insemination in non-sedated sows. Reproduction 122:289–296.[Abstract]
Martinez, E. A., J. M. Vazquez, J. Roca, X. Lucas, M. A. Gil, I. Parrilla, J. L. Vazquez, and B. N. Day. 2002. Successful non-surgical deep intrauterine insemination with small numbers of spermatozoa in sows. Reproduction 123:163–170.[Abstract]
Rath, D., C. Kruger, and L. A. Johnson. 1999. Low dose insemination technique: How many sperm do we need for successful insemination? Page 13 in Proc. IVth Int. Conf. Boar Semen Preservation, Beltsville, MD. (Abstr.)
Roca, J., G. Carvajal, X. Lucas, J. M. Vazquez, and A. Martinez. 2003. Fertility of weaned sows after deep intrauterine insemination with a reduced number of frozen-thawed spermatozoa. Theriogenology 60:77–87.[Medline]
Rozeboom, K. J., M. H. T. Troedsson, and B. G. Crabo. 2000. AI in Swine: The impact of inseminations on the uterine environment. Pages 177–184 in Boar Semen Preservation IV. L. A. Johnson and H. D. Guthrie, ed. Allen Press, Inc., Lawrence, KS.
Soede, N. M., D. W. B. Steverink, P. Langendijk, and B. Kemp. 2000. Optimized insemination strategies in swine AI. Pages 185–192 in Boar Semen Preservation IV. L. A. Johnson and H. D. Guthrie, ed. Allen Press, Inc., Lawrence, KS.
Soede, N. M., C. C. H. Wetzels, W. Zondag, W. Hazeleger, and B. Kemp. 1995b. Effects of a second insemination after ovulation on fertilization rate and accessory sperm count in sow. J. Reprod. Fertil. 105:135–140.[Abstract/Free Full Text]
Soede, N. M., C. C. H. Wetzels, W. Zondag, M. A. I. De Koning, and B. Kemp. 1995a. Effects of time of insemination relative to ovulation, as determined by ultrasonography, on fertilization rate and accessory sperm count in sows. J. Reprod. Fertil. 104:99–106.[Abstract/Free Full Text]
Steverink, D. W. B., E. G. Bouwman, N. M. Soede, and B. Kemp. 1997. The effect of semen backflow on fertilisation results in sows. Page 94 in Proc. 5th Int. Conf. Pig Reprod., Kerkrade, The Netherlands.
Vazquez, J. L., E. A. Martinez, J. M. Vazquez, X. Lucas, M. A. Gil, I. Parrilla, and J. Roca. 1999. Development of a non-surgical deep intrauterine insemination technique. Page 35 in Proc. IVth Int. Conf. Boar Semen Preservation, Beltsville, MD.
Watson, P. F., and J. Behan. 2002. Intrauterine insemination of sows with reduced sperm numbers; results from a commercially based field trial. Theriogenlogy 57:1683–1693.
Weitze, K. F., H. Wagner-Rietschel, D. Waberski, L. Richter, and J. Krieter. 1994. The onset of heat after weaning, heat duration, and ovulation as major factors in AI timing in sows. Reprod. Domest. Anim. 29:433–443.
Top
Abstract
Introduction
