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Mounting efficiencies, courtship behavior and mate preference of boars under multi-sire mating
Abstract
The mating behavior of boars toward a herd of sows in a mating pen was observed for 72 h at a commercial swine farm. Mating pens consisted of two to four purebred boars and eight crossbred sows. The observation was conducted on a total of four pens during summer 1987. Boars often mounted sows in estrus, but rarely attempted to mount anestrous sows. Total numbers of mounting events varied among boars in a pen. Mounting efficiencies (number of copulations per number of mounting events) were < 10% for most boars. There was a diurnal pattern in mounting events and the peak occurred at around 03.00 h. The observed courtship behavior of boars was broken down into seven categories: sniffing, head to head, nosing, following, chin resting, mounting and copulation. Sequence analysis was used to determine the pattern of the boars' preliminary courtship behavior before mating. The most frequently observed transition was from “head to head” to “nosing”, and “nosing” was located in the center of the courtship behavior pattern. It is likely that preferential mating exists between boars and sows in estrus.
... multi-sire mating system the sows are placed in large service paddocks at weaning together with a group of boars. This system differs in several aspects compared to the service system based on artificial insemination or supervised natural mating, where one boar is placed in a small pen with one estrus sow [4][5][6][7]. In a multi-sire mating system, there is no control of the individual mating, because the copulations take place with no or very little supervision. ...
... The observations began at dawn and continued until dark. One exception was the first observations period (July), when the observations were carried out 24 h/day, because we expected some sexual activity during darkness due to the relatively high temperatures in the daytime as previously observed in a Japanese study [4]. When necessary, an electric torch was used to identify animals The number of boars and sows in the group could vary between days because some animals were able to crawl under the fence and move from one paddock to another. ...
... The sow collapsed under the weight of the boar a [4,5]. b [9]. ...
An important aim of organic animal production is to allow natural animal behaviour. Regarding reproduction techniques, artificial insemination is permitted but natural mating is preferred. The outdoor multi-sire system, where the sows are placed in large paddocks with a group of boars, is one example of a service system, which complies well with the organic ideals of facilitating natural animal behavior. However, very little knowledge is available about such system. Seven groups of in total of 47 sows and 31 boars were observed to study the mating behavior in an outdoor multi-sire mating system and the subsequent reproduction results. The time of start of courtship, behavior and the cause of disruption if the courtship was terminated, were recorded each time a boar courted a sow. All aggressive interactions between the boars were also recorded to estimate the boar ranking order. The observations revealed numerous poor quality matings, a huge variation in the number of times sows are mated, and overworked boars. Only 35% of all copulations lasted 2min or more and 63% of all copulations were disrupted, mainly by competitor boars. The higher social status of the boar, the more copulations did it disrupt (p<0.05). The outcome was an unacceptable variation in reproduction results. Only 71% of all estrus sows conceived, corresponding to a pregnancy rate of 77% of all mated sows. A large inter-group variation in reproduction performance was observed, indicating scope for improvements. In some groups all sows showed estrus and all sows conceived. Recommendations for improvement of the system are proposed.
... The number of mounts, number of matings, number of mounts per mating, and mating efficiency when pen-mating four females per pen(Tanida et al., 1989). Mating behavior was observed for 72 continuous hours. ...
... The number of mounts, number of matings received per female, mating efficiency, and proportion of females mated during a 72-hour period of pen-mating(Tanida et al., 1989).All sixteen females were in estrus. b Number of matings divided by number of mounts x 100. ...
The master control switch of a pork production enterprise is weaning day. Pork production managers have little or no control concerning when a weaned female will cycle or how long she will be in estrus after weaning. When females are pen-mated, the producer needs to use management procedures to: (1) prevent an excessive number of estrous females from expressing the standing response at the same time in the same pen, (2) ensure estrous females are bred at the proper time, (3) maintain an adequate level of fertility in boars, (4) evaluate boars for semen quality, (5) evaluate boars for level of sexual behavior and mating dexterity before and during the mating period, and (6) heat-check gestating females. Regardless of the boar-to-female ratio used or the management procedures implemented, there is no guarantee that all pen-mated females will be satisfactorily serviced during their first estrus after weaning. This publication discusses in detail the cause of problems that occur when pen-mating female pigs and provides possible solutions to the problems.
... The proportion of copulations occurring between 0200 and 1100 was 80.5%. These results are in agreement with studies on single and multisire matings (Tanida et al., 1989Tanida et al., , 1990Tanida et al., , 1991). The number of matings shown inTable 3 may seem low for 18 boars; however, the number of matings per boar was affected by sexual behavior classification, as later described in the section on cohabitation procedure. ...
... ings for the three INT boars during cohabitation was 2, 5, and 7. Only one L boar copulated twice. The percentage of estrous females mated during cohabitation was 66.7 ( 8 of 12), 33.3 ( 4 of 12), and 8.3% ( 1 of 12) for H, INT, and L boars, respectively. The percentage of estrous females mated by H and INT boars was low because of mate preference. Tanida et al. (1989) found that only 75% (12 of 16) of estrous females were mated when two to four boars cohabitated with eight females after weaning. A second study indicated that boars tend to select mating partners rather than courting at random (Tanida et al., 1991). ...
This study used three separate methods to evaluate sexual behavior in boars previously classified as having high (H), intermediate (INT), or low (L) levels of sexual behavior. Boars were initially evaluated for sexual behavior at 9.6 to 10.6 mo of age with a tethered female for 5 min. Boars were subsequently evaluated with a tethered female for 10 min (TF), a group of females for 10 min (FG), or continuously in a cohabitation environment for 113 h (C). When boars were evaluated with the TF procedure they mounted the female in less time (P < .01) and copulated sooner (P < .01) than when evaluated with the FG procedure. Regardless of whether the TF or FG procedure was used, L boars cumulated less time (P < .01) nosing the sides of females and took longer (P < .01) to first mount than H or INT boars. Proportion of successful matings was not different between the TF and FG procedure; however, the proportion of successful matings by H (91.7%), INT (79.2%), and L (45.8%) boars did differ (P < .001). With the C procedure, sexual behavior classification affected (P < .01) average number of successful matings (H, 4.7; INT, 2.3; and L, .33). This study indicates that sexual behavior traits expressed by a boar are similar when evaluated with a tethered female, a group of females, or a cohabitation environment.
... Free-range male donkeys approach the female many times and then withdraw before ultimately approaching and engaging in coitus, with the expression of male sexual behaviour stimulated by the behaviour of the female (Henry et al., 1998). Sexually aroused boars emit a short series of characteristic grunts, snap their jaws, salivate, urinate frequently, sniff the reproductive organs and head of the sow (Signoret, 1970;Tanida et al., 1989;Grigoriadis et al., 2000), and hit her abdomen with their snout. ...
The article contains a literature review of facts and views on the strategies of sexual behaviour in mammals, taking into account the role of the animal’s species, sex, and position in the herd. The role of the senses, brain, and hormones in the expression of animals’ sexual behaviour is discussed, as well as the role of induction of the coitus reflex and social behaviour in the reproduction of present-day wild and domesticated animals. The analysis shows that the predominant strategy of sexual behaviour in females is to attract multiple potential partners to acquire the best male. The predominant strategies in the sexual behaviour of males of most mammalian species are aimed at fertilizing as many females as possible. Expression of sexual behaviour requires the generation of a set of characteristic sexual reflexes that indicate readiness to copulate and are sexually stimulating. Animals are differ in expressing their sexual behaviour. Some individuals react quickly and dynamically to sexual stimuli and immediately begin coitus, while others require longer preparation for successful coitus. Sexual behaviour influences the status of individuals in some species. Wild mammals with high expression of the sexual behaviour typical of a given species usually occupy a dominant position, which gives them an advantage in the search for breeding partners, access to food, and the expression of preferred social behaviour. Expression of sexual behaviour is stimulated by stimuli from potential sexual partners, which induce copulatory reflexes. These reflexes have been described in numerous animal species. They should be generated in the proper order and proceed without disruption for successful coitus and fertilization to occur.
... A high libido score was therefore associated with excellent sexual behaviour. and sow lead to substantially reduced mating efficiency in a penmating system [34]. Therefore, it is of great importance to keep at least two boars of different age and body size to guarantee successful NM in gilts as well as sows. ...
Although artificial insemination in pig production is widespread, many farms rely on natural mating (NM). For NM to be successful, adequate sexual behaviour and a sufficient libido level in boars is crucial for appropriate reproductive performance. Therefore, this observational study evaluated the libido level of 59 boars of different breeds used for NM by a scoring system ranging from 0 (no libido) to a maximum of 23 points (perfect libido) and analysed their general and andrological health as well as housing and management factors influencing the libido.
The boars showed a mean libido score of 16.7 (SD ± 2.3). Crossbreed (median: 17.5, min: 14.0, max: 21.0) (p < 0.01) and Landrace (median: 17.5, min: 17.0, max: 21.0) (p < 0.05) boars showed significantly higher libido scores compared to Piétrain boars (median: 14.0, min: 13.0, max: 17.0). A non-slippery mating area was found to be positively associated with libido (p < 0.05), whereas disorders such as lameness showed a negative correlation (p < 0.01). In winter, significantly higher libido values (median: 17.0, min: 14.0, max: 21.0) were recorded compared to spring (median: 16.0, min: 11.0, max: 21.0) (p < 0.05). In addition, high number of supports by farmers during natural mating and frequency of use for NM and for stimulation of artificially inseminated sows did not negatively influence the libido score. No significant correlation between the satisfaction of the farmer about the libido level of the boars and the evaluated libido score was detected.
This is the first study investigating the effect of housing conditions and management procedures on the libido of boars used for NM under field conditions. The findings may therefore help to establish a successful mating management for herds applying NM on a regular basis. A systematic evaluation of the libido score is needed to detected boars with low libido levels, because it is often overlooked by the farmers. Moreover, genetics, general health condition and flooring in mating areas turned out to be critical parameters that influence the libido score of boars used for NM and therefore should be considered when examining natural mating on farm.
... Desweiteren zeigten die Untersuchungen , dass Eber während der heißen Jahreszeit nachts sexuell aktiver werden, obwohl Schweine tagaktive Tiere sind (Wechsler, 1997 ). Dabei finden die meisten Aktivitäten zwischen Mitternacht und Morgendämmerung statt (Tanida et al., 1989). Dennoch werden die Eber in Schweinebetrieben ohne Berücksichtigung der hohen Sommertemperaturen im Laufe des Tages genutzt, im Einklang mit den anderen täglichen Routinen. ...
Pig breeding farms have lower production results due to high temperatures in summer since difficulties in pig reproduction may be observed due to stress caused by unfavourable environmental conditions. It was confirmed that certain substances can reduce stress and consequently enhance reproduction. Therefore, the goal of this research was to analyse those elements in the behaviour of boars that could be influenced by heat stress and continuous seevice for artificial insemination, and to examine if the negative influence can be reduced with a feed supplement (Ascogen®) or an immunomoduator (Baypamun®). In the study, 36 boars were randomly divided in four groups, and assigned to different treatments: the first group was treated with Asco-gen®, the second group was treated with Baypamun®, the third group was treated with Ascogen® and Baypamun®, while the fourth group served as control. It was found that all treated groups were generally more active in comparison with the control group, what could mean that they coped better with summer conditions. The group of boars that was treated with Ascogen® and Bay-pamun® spent significantly more time in eating and drinking; furthermore, the boars in that group were resting less time than the boars in other treatment groups. The three groups of boars that received treatment were statistically not more successful in reproduction, although generally they had better results than the control group. Therefore, we concluded that further studies with more animals could explain underlying mechanisms with more details and clarify the meaning for the welfare of boars.
... In swine farms, it is sometimes observed that when sows in estrus are put together with males for mating purposes, some of the latter do not show any interest in some females, and also, some females apparently do not allow some males to mate them. It has also been seen that some males need to perform a larger number of persuasions in order to copulate [30][31][32]. ...
When a sow copulates with different boars, fecundation can take a slant towards the best quality male, which should have a more competitive ejaculation. In polyandric animals, genitals can be more elaborated and be an indication of spermatic competence or cryptic female choice. In swine, the male and female genital morphologic characteristics are evidence that allow the assumption of spermatic competence and cryptic choice in this species. In order to prove this hypothesis, the paternity of a group of 18 York/Landrace (Y/N) sows was determined; these sows copulated with three boars: Yorkshire (Y/Y), York/Landrace (Y/N) and Landrace (N/N). The three boars had the same probability of copulating in the first, second, and third place with each of the sows in an interval of 12 hours between each mating. Four polymorphic molecular markers were used in order to establish the paternity (S0033, S0035, S0036 and S0037). The results indicate that the Y/N male had 85.59% of paternity, Y/Y male 8.8% and N/N 5.8%. According to the mating order, when the Y/N male copulated in the first place, it had 89.6% paternity (26 offspring; 12 males; 46.15% and 14 females, 53.85%) when it copulated in the second place, it had 100% paternity (8 offspring; 4 males, 50% and 4 females, 50%), and when it mated in the third place, it had 77.41% paternity (22 offspring; 13 males, 59.1% and 9 females, 40.9%). Sows in estrus participated in the removal of semen from four sows minutes after the copula by female-female mating. The multiple mating allowed certain competence among the ejaculation and the possibility of the female to slant the paternity towards the heterozygote male with higher genetic variability, compared to the homozygote male (Y/Y and N/N).
Reproductive and maternal behaviors of major livestock species are discussed in terms of their evolutionary origins, genetic influences, and heritability, and the effects on them of domestication, artificial selection, intensification, and environmental change.
This chapter describes the reproductive and maternal behaviors of different livestock species (cattle, horses, pigs, goats, and water buffalo) with an emphasis on those traits which are genetically conserved. All of the species discussed are polygynous and promiscuous, and females undergo estrous cycles in which males are mainly attracted by movement and posture cues. Major differences in both reproductive and maternal behaviors are observed between "prey" and "predator" type species. Genetic variation also occurs within species, with breed and line differences being observed in all of the behaviors discussed, allowing selection for optimal reproductive and maternal behaviors. However, modern livestock systems, which emphasize production traits, can diminish reproductive and maternal traits and increase detrimental behaviors, such as piglet crushing and savaging in sows. With modern selection tools, greater emphasis on positive reproductive and maternal traits is achievable within the context of profitable production.
The behaviour of 80 gilts and 14 boars was observed over a 54-day period in a dynamic service system with pens of 20 gilts and 4–5 boars. The female population of this system was changed on a regular basis (four animals in four animals out per week) while boars were resident. Altogether 933 mating attempts (MAs) were recorded and their quality was classified using quantitative behavioural criteria. Only 9% and 18% of the observed MAs were classified as `very good' and `good', while 14, 24 and 35% were `fair', `poor' and `very poor', respectively. Differences between and within boar teams in the mating quality parameters were significant (all p
The effect of intermittent electroshock and housing on sexual proceptive behaviour shown in the home pen was studied in pair-housed and individually housed gilts. In addition, the effect of intermittent electroshock on the behavioral response to boar stimulation and on sexual receptivity during the first oestrus was studied in pair-housed gilts. From 115 to 168 ± 2.6 days of age, 24 female pigs were subjected to inescapable electroshocks administered 0-5 times daily between 08:00 and 16:00 and 24 female pigs served as controls. At 168 ± 2.6 days of age the gilts were given 30 min full boar contact. Immediately after the initial boar contact the gilts were assigned within stress treatment to either pair-housing (12 control and 12 electroshocked gilts) or individual housing (12 control and 12 electroshocked gilts). Oestrus detection was carried out twice daily from then on. Behaviour in the home pen was observed in all 48 gilts during the first and second day of the first oestrus and during two control days 5-8 days after oestrus. The behavioral response to boar stimulation and sexual receptivity were observed on the 24 pair-housed gilts in 5-min tests carried out the day after the initial boar contact and during the first day of oestrus, respectively. Intermittent inescapable electroshocks affected neither the behavioral response to boar stimulation nor the sexual receptivity and proceptive behaviour in the home pen. The behavioral response was, however, of importance for the stimulatory value of the boar in that gilts which showed high levels of fear of the boar during stimulation had a lower probability of attaining puberty within 10 days after the initial boar contact. The proceptive behaviour shown in the home pen was both quantitatively and qualitatively different for individually housed and pair housed gilts, which may be of importance for the ease of oestrus detection as well as for the behavioral indicators that could practically be used for heat detection.
The sexual behaviors of pigs were observed at a commercial farm to study the selection of mating partners in boars and estrous sows under multi-sire mating. In Experiment 1, three sire groups and nine sow groups were used to characterize the courtship behavior between boars and sows. The flow diagram of the behaviors constructed by sequence analysis revealed that ‘nosing’ by boars played an important role to induce sows to stand still, which in turn motivated boars to mount. In Experiment 2, two sire groups and four sow groups were used. Each sire group consisted of three Duroc boars raised from the same litter. Each sow group consisted of eight crossbred sows in which estrus had been induced. Each sire group was assigned to a sow group for 48 h, and their sexual behaviors were recorded continuously with an infrared camera connected to a time lapse video recorder. The same procedure was repeated 3 months later with the same sire groups and different sow groups, which made two observations per sire group. Time spent on courtship behavior with each sow varied significantly (P<0.001) within each set of three boars. The boars spent longer times on courtship behavior and mounted and copulated more frequently with some specific sows than with others. The dendrogram constructed, based upon the time spent on courtship behavior between a sow and a boar, showed that boars and sows had a tendency to select mating partners and that some boars received more attention from sows than others. The cell by cell test on the number of mounts from boars to sows indicated that each boar had a favorite mate or mates (P<0.05). It is likely that selection of mating partners exists between boars and sows in estrus.
The differences in conditions in outdoor systems compared to indoor systems were expected to influence the reproduction performance of outdoor sow herds. The differences include e.g. loose-housing, groups of animals and climatic factors as well as registration routines. Sow records were analysed from three Danish and one Scottish outdoor herd. In the analyses the reproduction cycle (days between farrowings (DFAF)) was divided into the three sub-periods: days from farrowing to weaning (DFAW), days from weaning to first recorded service (DWSE), and days from first recorded service to farrowing (DSFA). In addition, the analyses included days from farrowing to culling (DFCU). Explanatory variables were herd, parity, year, serving system and season as well as relevant interactions. The average herd level was 149.9 days for DFAF, 28.0 days for DFAW, 5.6 days for DWSE, and 116.2 days for DSFA, which is similar to levels observed in indoor systems. The average level for DFCU was 27.7 days. The identified variation was limited and comparable with the usual range in sow herds. The effect of the explanatory variables could often be ascribed to specific registration and management practices. There was a tendency for DFAW to be lower in April (26 days) compared to October (27 days). In addition, there was a tendency for DWSE to be higher in herds with uncontrolled servings (4.9 days) compared to herds with controlled servings/artificial inseminations (AI) (6.5 days). In herds with uncontrolled servings, DFAW tended to increase in July to February. In herds with controlled servings/AI, DWSE tended to increase in January to April.
The mating management of pigs is conducted under a wide spectrum of management techniques because females are variously hand-mated, pen-mated, or artificially inseminated. Factors that may affect the onset of estrus when hand-mating are boar exposure, method of housing females after weaning, season, type of facilities, and parity. The expression of sexual behavior in both male and female pigs can be influenced by a variety of physiologic, psychological, and environmental factors. To optimize the efficiency of estrous detection, females should not receive boar stimuli just prior to estrous detection when either hand-mated or artificially inseminated. When females are pen-mated, management procedures need to be employed to prevent an excessive number of estrous females from accumulating, which leads to a decrease in boar fertility.
To examine the importance of visual, auditory and olfactory stimuli from the mature boar in eliciting proceptive behaviour in the mature female pig, 60 Large White × Landrace sows were randomly allocated to be tested for appetitive behaviour in T-maze preference tests. Various combinations of the boar-component stimuli (visual, auditory and/or olfactory cues) were presented to the sows as a choice in the arms of a T-maze. The relative attraction of the sows towards the various combinations of stimuli presented was interpreted as showing that these stimuli elicited proceptive behaviour in the sow. The proceptivity of the sows was assessed during oestrus (sexual receptivity), immediately after oestrus and during anoestrus (pregnancy).Analysis of the 928 T-maze preference tests carried out in this experiment indicated that visual cues from the boar were of primary importance in eliciting sow proceptivity during the oestrous period. However, when no visual cues were presented, olfactory stimuli from the boar became important in orientating the proceptive behaviour of the oestrous sow. Sows exhibited significant preferences for boars releasing androstene pheromones in saliva over boars unable to release salivary androstenes when neither boar could be seen. In the absence of both visual and olfactory stimuli, there was some evidence for the involvement of auditory cues from the boar in eliciting proceptive behaviour in the females. Proceptive behaviour was significantly related to the receptive state of the female at oestrus — declining during post-oestrus and rarely being exhibited significantly during anoestrus. It is suggested that deficiencies in olfactory stimuli (salivary androstenes) from the boar may be responsible for mate preferences exhibited by some sows under intensive husbandry conditions.
The aim of this study was to investigate the stimulus value and mating success of young boars in the presence or absence of exogenous boar-originating stimuli. Ten Large White × Landrace boars were exposed to each of the following treatments at 6 – 7 months of age (Period 1) and again at 9 – 10 months of age (Period 2): (1) no added boar stimuli; (2) added auditory stimuli; (3) added olfactory stimuli; (4) added auditory and olfactory stimuli. The efficacy of each treatment was determined by subjecting each boar to 2 × 5-min mating tests during each age-period, and assessing gilt proceptivity and sexual receptivity. Gilts used in these tests had been ovariectomized and were induced into behavioural oestrus using a threshold dose of oestradiol benzoate.The addition of both exogenous boar-originating stimuli (Treatment 4) significantly (P<0.05) increased gilt proceptivity and sexual receptivity in Period 1. This indicates that young post-pubertal boars may be deficient in both the auditory and olfactory stimulation that they provide to the female pig. No significant differences were observed between treatments during Period 2. These results therefore suggest that young boars (6–7 months of age) may have a lower stimulus value than their older counterparts, and that this may adversely affect mating success.
Scientific literature on pig behavior and its practical applications was reviewed and discussed. Areas were identified where behavioral research is likely to produce major benefits in productivity. It was noted that some husbandry practices appear to be out of harmony with the behavior of domestic animals, and that an imaginative research effort is needed to improve confinement rearing of pigs.
The sexual behavior of individual cats was described and examined using the "sexual exhaustion and recovery" technique. In Normative Tests, the behavior of five males tested with three females was quantified. The males gripped the females after 16 seconds and achieved their first intromission after 107.5 seconds on the average. Mating continued until approximately seven intromissions occurred. The frequency and spacing of intromissions were a function of the particular individuals in the mating pair. The duration of the intromissions was primarily a function of the female partner. Even though the probability of intromission per unit time declined during each test, the males recovered completely within 24 hours. Performance 24 hours after sexual exhaustion was the same as performance during tests spaced two weeks apart. At the point of sexual exhaustion the male could be rearoused to renewed mating if a sexually fresh female was presented. When a sexually fresh male was presented to a sexually exhausted female little mating resulted. The cessation of mating seemed to be primarily a function of the state of the female, although stimulus adaptation on the part of the male did seem to contribute. The data were discussed in terms of momentary and persistent components of sexual arousability. It was suggested that mating performances may be controlled by the rewarding properties of intromission and ejaculation.
The sexual behavior of individual cats was described and examined using the "sexual exhaustion and recovery" technique. In Normative Tests, the behavior of five males tested with three females was quantified. The males gripped the females after 16 seconds and achieved their first intromission after 107.5 seconds on the average. Mating continued until approximately seven intromissions occurred. The frequency and spacing of intromissions were a function of the particular individuals in the mating pair. The duration of the intromissions was primarily a function of the female partner. Even though the probability of intromission per unit time declined during each test, the males recovered completely within 24 hours. Performance 24 hours after sexual exhaustion was the same as performance during tests spaced two weeks apart. At the point of sexual exhaustion the male could be rearoused to renewed mating if a sexually fresh female was presented. When a sexually fresh male was presented to a sexually exhausted female little mating resulted. The cessation of mating seemed to be primarily a function of the state of the female, although stimulus adaptation on the part of the male did seem to contribute. The data were discussed in terms of momentary and persistent components of sexual arousability. It was suggested that mating performances may be controlled by the rewarding properties of intromission and ejaculation.
A factorial experiment is described in which thirty-six aged and thirty-six maiden spayed crossbred ewes were used in four successive tests at intervals of 15 days in a study of factors affecting the detection of oestrus. Variates introduced into each test were: ( a ) freedom of rams (free or tethered); ( b ) size of mating paddock (17 acres or ⅕ acre); ( c ) age of ewe (maiden or aged); and ( d ) dose of oestrogen (oestradiol benzoate, ODB: 10·0, 15·6, 24·4 μg.).
All ewes were primed with progesterone for 12 days prior to ODB injection and joining. The number of ewes detected in oestrus and the number and identity of rams which served each ewe were recorded.
In the four successive tests 29, 33, 36 and 30 ewes were served.
Significant main effects were: ( a ) freedom of rams—free 77, tethered, 51 ( P < 0·001); ( b ) size of mating paddock—17 acres 49, ⅕ acre 79 ( P < 0·001); ( c ) age of ewes—aged 57, maiden 71 ( P < 0·05); and ( d ) dose of ODB—10·0 μg., 20; 15·6 μg., 41; 24·4 μg., 67 ( P < 0·001).
Significant interactions were: ( a ) test number × age ( P = 0·01), and ( b ) test number × dose of ODB ( P < 0·05). The number of maiden ewes served increased and that of aged ewes decreased withsuccessive tests. There was a barely significant ohange in the slope of the ODB D/R line.
Ewes showed no obvious preference for tethered rams of any particular breed. There was a positive correlation between the performance of rams when free and tethered.
The influence of the odoriferous androstene steroids upon the response and courtship behaviour of gilts has been studied. These steroids are normally present in the submaxillary salivary glands of the boar, and have been shown previously to be an aid in the artificial insemination of gilts. Glands were excised from young boars after weaning, and at 6 months of age the ability of the boars to elicit a standing response from oestrous gilts was compared with that of littermate controls. In addition, a detailed record was made of behavioural activities performed by both gilts and boars, under a standard test procedure.
Analysis of the data showed that the presence of the glands was essential for normal behavioural patterns in both the females and the males. When confronted with a treated boar, the gilts were affected in three ways: approaching oestrus, they did not respond as early as they did to the controls; the intensity of their response was reduced; and it was held for a shorter period. The demeanour of the treated males was passive and unconcerned, i n contrast to the easily-aroused aggressive nature of the controls. The characteristic viscous salivary secretion was absent, and the scrotal sac was less pronounced and supported closer to the body.
These results suggest that elimination of the white, frothy saliva normally containing and dispersing the androstene steroids not only reduces the boar's ability to command and elicit a full sexual response from oestrous gilts, but it also reduces his own libido. In conjunction with previous work, these studies provide evidence for the pheromonal properties of androstenone and androstenol.
Two studies were carried out at a commercial piggery to examine the importance of the courting behaviour of the boar on the fertility of both natural and artificial matings. In the first study the sexual behaviour of 24 breeding boars of known conception rate was observed. A significant correlation (r = + 0.48, P < 0.05) was found between the number of times the boar nosed the sides of the female and his conception rate record. In the second study 68 sows that were housed singly or in pairs were either artificially inseminated or briefly courted by a boar prior to artificial insemination. Allowing sows that were housed in pairs to be courted by a boar increased conception rate from 62.1 to 86.7% (P > 0.05) and litter size from 8.6 to 10.3 (P < 0.05) while for those sows housed singly these two parameters were decreased from 66.7 to 50.0% (P > 0.05) and 11.9 to 6.7 (P < 0.05), respectively. The two studies demonstrate the importance of the sociosexual environment on the fertility of natural and artificial matings.
The effect of aerosols containing six related androgen steroids, either singly or in combination, were compared by observing the reaction to the "back pressure" test of pigs presented for insemination. All tests were carried out on pigs not kept in the vicinity of a boar and which had given an initial negative response to back pressure.
The effect of aerosols containing different concentrations of 2 related steroids (5α-androst-16-en-3-one and 3α-hydroxy-5α-androst-16-ene) on the reaction to the “back pressure” test on pigs presented for insemination, in the absence of the boar, was compared with that of preputial fluid. In view of the positive response following application of these steroids in pigs previously negative to the “back pressure” test, the effect of aerosol sprays containing the 5α-androst-16-en-3-one steroid was compared, in a second similar investigation, with that of control blank aerosols. Of the 101 pigs tested with the steroid-containing aerosol, 46 per cent gave a subsequent positive response to the “back pressure” test compared with a nil response in the 64 pigs tested with the blank aerosol control. The possible advantages from the use of such steroid aerosols in routine A.I. to improve response to the “back pressure” test are discussed.
(1) Potential ethological isolating mechanisms were observed between breeds and strains of domestic fowl. (2) Brown and White Leghorn females exhibited homogamy, but females of a Broiler strain showed a preference for Breeding Line Brown Leghorn males, which bear a close phenotypic resemblance to the Red Jungle fowl (Gallus gallus spadiceus). (3) Observations indicated that females discriminated between males on physical characteristics rather than quantitative differences in male courtship. (4) In a ''choice-situation'', males which had been reared with own-breed females courted caged own-breed hens significantly more than others. Males reared with their own and other breeds showed only weak own-breed preferences, and in two cases, heterogamy was observed. (5) Males apparently discriminated between females on visual cues, particularly female plumage colour. (6) Assortative mating within a single line was also observed, females preferring some males to others. Quantitative differences in male courtship were not important in this respect. (7) In tests of short duration, males did not exert preferences for individual hens of a single line. (8) A sequential analysis of the courtship of the Brown Leghorn cock revealed that two displays were important in evoking female solicitation, namely the waltz and the rear approach. Three other displays were interpreted as increasing sexual arousal in the female. (9) The evolutionary significance of some of the results is briefly discussed.
The Science of Animal Husbandry 4th edn
- J Blakely
- D H Bade
Blakely, J. and Bade D.H., 1985. The Science of Animal Husbandry 4th edn. Reston Publishing Company, Reston, VA, 683 pp.
Domestic Animal Behavior
- J V Craig
Craig, J.V., 1981. Domestic Animal Behavior. Prentice-Hall, Englewood Cliffs, NJ, 364 pp.
Estrus synchronization in weaned sows through self-feeding during lactation period and by simu!taneous weaning. 1. Interval from weaning up to first estrus and number of synchronized sows
- Y Kasuya
- N Abe
- K Kawabe
Kasuya, Y., Abe, N. and Kawabe, K., 1980. Estrus synchronization in weaned sows through self-feeding during lactation period and by simu!taneous weaning. 1. Interval from weaning up to first estrus and number of synchronized sows. Japn. J. Swine Sci., 17: 16-22.
The behavior of swine The Behavior of Domestic Animals
- J P Signoret
- B A Baldwin
- D Fraser
- E S E Hafez
Signoret, J.P., Baldwin, B.A., Fraser, D. and Hafez, E.S.E., 1975. The behavior of swine. In: E.S.E. Hafez (Editor), The Behavior of Domestic Animals. 3rd edn. Bailliere TindaU, London, pp. 295-329.
Estrus synchronization in weaned sows through self-feeding during lactation period and by simultaneous weaning. 1. Interval from weaning up to first estrus and number of synchronized sows
- Kasuya