Interaction effects of sexual preparation and

diurnal period on reproductive capacity of boars

5 Programme 3: Farmer Support and Development5.1 Strategic Goals• Goal 1 – Improvement of primary production and advancement

in agro-processing• Goal 2 – Economically suitable agricultural development• Goal 4 – Improved stakeholders relations• Goal 6 – Household food security• Goal 7 – Farmer settlement support

T. Teele1 and D.O. Umesiobi2#

1 Extension and Advisory Services, Department of Agriculture and Rural Development, P O Box 50, Parys, 9585

2 School of Agriculture and Environmental Sciences, Central University of Technology, Free State, Private Bag X20539, Bloemfontein, 9300, South Africa

#Corresponding author: E-mail: umesiobi@cut.ac.za

Contents• Introduction• Motivation of the study• Problem statement• Project rationale• Objectives• Hypothesis• Research design and methodology• Statistical analysis• Results and discussions• Conclusions and recommendations• References• Acknowledgements

Introduction Successes in the pig production industry therefore depend

mostly on the sexual drive of the boar and the ability to produce semen of a required quality with a large number of normal live sperm for optimum fertilization capacity of sows (Umesiobi et al., 2002; Umesiobi, 2007).

Increasing use of assisted reproductive techniques in the pig has exposed a need for additional aids such as sexual preparation of boars, involving sexual restraint and false mounting, to help animal reproductive physiologists and breeders optimise the ejaculates obtained from boars

Orgeur and Signoret (1984), Price (1987), Umesiobi and Iloeje (1999) and Umesiobi et al. (2004) observed that the male, if not stimulated to a high level of excitability, becomes somnolent and sluggish in sex drive and the ejaculatory reflex weakens

Motivation of the study Numerous studies (Umesiobi & Iloeje, 1999; Umesiobi

et al., 2002; Umesiobi, 2006a, b; Umesiobi, 2008a, b, c) have been conducted to optimise the reproductive potential of artificial insemination (AI) pigs to equal or better that of natural mating, conception rate and litter size are less than optimal in most production systems (Umesiobi et al., 2004).

Boars that obtain adequate sexual preparation exhibit a relatively rapid ejaculation rate, and are capable of inseminating a greater number of females per unit time than males with poorer sexual drive (Umesiobi, 2004)

The interaction effect of sexual preparation and diurnal period on reproductive capacity of boars has not been determined

Problem statement Sexual preparation of boars has not received adequate

attention from researchers Precise guidelines are not available Boars should be subjected to a few minutes of sexual

restraint and false mounting before they are used for breeding

Reproductive performance is most critical in boars with low sexual drive

Larger number of boars are needed to sire offspring that grow faster and yield more meat

Project rationale Boar sexual drive is a critical feature of a breeding

system in which a predetermined number of females are to be bred weekly.

Sexual drive and semen viability should not be taken for granted, especially during the summer months.

Boars are temperamental and individualistic. Some boars possess many desirable traits, and are

aggressive and fertile; others are sterile or possess no sex drive.

Although boars that lack a sex drive are self-eliminating, they cause additional problems because the other boars must be used more frequently to compensate for them.

ObjectivesThe primary aim and objectives of the study The primary aim of this study was to determine the

interaction effects of sexual preparation and diurnal period on reproductive capacity of boars

In order to achieve this aim, the following objectives were achieved: A literature review was conducted to gain insight and

perceptions on current views of the principles of the role of sexual preparation and diurnal periods on reproductive capacity of boars.

The principles of the role of sexual preparation and diurnal periods were utilised to identify fundamental performance indicators by means of which the reproductive capacity of boars were evaluated.

Specific objectives and HypothesisA field experiment was conducted to determine: the interactive effects of sexual preparation on

reproductive capacity of boars, and the effects of diurnal periods on reproductive capacity

of boars

Hypothesis Sexual preparation and diurnal period has significant

interaction effect on reproductive capacity of boars

Research design and methodology

Twelve Large White boars (aged 2.0 years) and 36 sows of the same breed and age were randomly selected

The experimental boars were trained to mount the artificial sow at 6 to 8 months of age

The research protocols were conducted in 4.5 m x 4.5 m pig pens.

Individual pens had a combination of concrete and solid steel rod flooring and were each equipped with a nipple waterer.

The animals were limit-fed, at a rate of 2 kg/day

Research design and methodology

SEXUAL PREPARATION AND BOAR SELECTION Prior to sexual preparation, the boars were randomly

recruited and trained for two weeks two ejaculates were collected in 12 hour interval 0, (0R) 5 (5R) and 10 (10R) sexual restraint (sexual

preparation) tests Libido was recorded as the reaction time (RT) (in

minutes) 30 minutes reaction time at 8:30 and 14:30 hours

(diurnal period) Semen was collected by the use of a gloved hand

device following sexual stimulation

Research design and methodology

SEMEN COLLECTION AND EVALUATION Semen was collected immediately after 0MR, 5MR and

10MR of sexual preparation at 8h30 and 14h30 diurnal periods, Twelve mature Large White boars were used to collect

semen over receptive sows on oestrus. Semen was collected by artificial vagina (AV) and

immediately strained through cheese-cloth to remove the gelatinous portion.

Artificial vagina device connected to a graduated semen bottle for easy semen evaluation

Research design and methodology

SEMEN COLLECTION AND EVALUATION The sperm-rich fraction was considered to be that portion of the

ejaculate that was distinctly ‘milky’ in appearance as opposed to the ‘watery’ pre and post-sperm fractions.

Semen volumes in ml were recorded after collection. Semen characteristics were analysed at the Agriculture

Laboratory of the Central University of Technology, Free State, while other characteristics were analysed at the Veterinary Laboratory, National Veterinary Division of the Department of Agriculture, Bloemfontein.

Motility was analysed under microscope while SpermCueR hemacytometer was utilised for the determination of sperm concentration. Progressive sperm motility (%) was estimated from 0 to 100 using a light microscope (Umesiobi, 2004; Umesiobi et al., 2004).

Research design and methodology

SEMEN COLLECTION AND EVALUATION The percentage of live sperm cells was determined by

vital staining with eosinnegrosin stain. The acrosomal morphology was assessed by mixing a

high grade Indian ink with semen on a slide and the mixture then drawn out to make a thin smear.

The smear was read using a light microscope at x400 magnification.

Semen from each experimental group was then collected and sperm cells from each boar were used (3 x 109 sperm/80 ml/sow) to artificially inseminate 3 oestrus-synchronised sows (twice), 12 and 24 hours after the onset of oestrus (Umesiobi and Iloeje, 1999; Strzezek et al., 2000).

Statistical analysis Data were analysed using the general linear model

procedure of SAS (2002 SAS, Version 9.1). The statistical model included sexual restraint

classification of boars (0, 5 and 10R) and individual boars (breeding boar) within treatment groups.

As libido test data for mounts, reaction time and ejaculations were discrete, these were analysed using the Wilcoxon signed rank test, and presented as least-square means (― s.e.).

ResultsSemen viability parameters

0 MR 5 MR 10 MR

08h30 14h30 08h30 14h30 08h30 14h30

Semen volume (ml) 113.35 ± 13.64a

103.23 ± 6.15a 116.67 ± 8.82a 123.33 ± 5.23ab 117.50 ± 10.7b 120.81 ± 9.16c

Motility (%) 69.16 ± 3.74a 63.31 ± 3.8a 66.71 ± 2.47a 72.5 ± 4.42b

 60.83 ± 2.39bc

 70 ± 2.58c

Semen concentration per ml (x106)

655 ± 10.45a 680.4 ± 35.36a 702.8 ± 57.14a 762.29 ± 39.1b 736.5 ± 58.53c 670.5 ± 40b

 Semen conc. per ejaculate (x109)

112.81 ± 2.66a

107.83 ± 3.47a 113 ± 2.77a 112.93 ± 1.76a 108.85 ± 3.34b 109.55 ± 3.37c

Live sperm (%) 61.67 ± 3.57a 66.17 ± 2.89a 64.17 ± 3.27b

 67.5 ± 2.14bc

 60.83 ± 3.26b

 70.83 ± 3.52c

 Normal sperm (%) 60 ± 2.24a

 60.83 ± 2.71a 63.33 ± 5.1a 56.67 ± 2.79b 66.6 ± 5.11c

 62.5 ± 2.81d

Acrosome morphology:

           

Normal apical ridge (%)

56.5 ± 3.09a 68.5 ± 7.82a 56.16 ± 4.33a

 61.2 ± 4.61b

 65.67 ± 4.4bc

 74.33 ± 3.46c

Damage apical ridge (%)

31.83 ± 12.85a

16.67 ± 5.26a 21.83 ± 5.54a

 25.5 ± 5.9ab

 18.17 ± 6.7b

 7.66 ± 4c

Missing apical ridge (%)

8 ± 1.88a

 8.65 ± 2.75a 15.33 ± 3.22b

 6.16 ± 7.11a

 7.5 ± 1.28ab

 6.48 ± 2.73c

 

Results and discussions• Sexual restraint of 10 min (10R) at 8:30 hours

(diurnal period) resulted in the highest number of mounts, ejaculation rate and shortest reaction time

• Volume, motile spermatozoa, semen concentration per ml improved at 10R 08:30

• Semen concentration per ejaculate (x109), live sperm and normal sperm were significantly improved with 5R at 14:30 and 10R at 08:30 and 14:30, respectively, with highest values recorded with 10R at 08:30 hours

Conclusions and recommendations

• This study suggest that boars sexually stimulated at 5 minutes during the afternoon hours (5MR14h30) significantly improved boars some of the semen characteristics

• However, boars sexually prepared at 10MR8h30 in the early hours persistently produce optimum sperm viability, with improved reproductive capacity

• 10 min of sexual restraint of boars conducted during the morning hours were most suitable for semen collection and use in AI services

References Flowers, W. L. 1997. Management of boars for efficient semen

production. J. Reprod. Fertil. Suppl. 52:67–78. McDonald, J.H. 2008. Handbook of Biological Statistics. Baltimore,

Maryland: Sparky House Publishing, pp. 1-28. Morrow, M. E. W., 2005. Semen extension: A comparison of methods.

Swine News 28(8): 35-39. Price, E. O. 1987. Male sexual behaviour. Vet. Clinics of North America:

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Umesiobi, D. O. 2006a. The effect of hemi-orchidectomy on reproductive traits ofboars. South African Journal of Animal Science 36(3): 181-188.

Umesiobi, D. O. 2006b. Effect of oral administration of Clomiphene citrate on sperm viability and fertility of boar semen. J. Appl. Anim. Res. 30: 167-170.

References Umesiobi, D. O. 2007. Measures of libido and their relation to testicular hypertrophy and

fertilizing competence in boars. Journal of Animal Science 85(Suppl. 1): 815. Umesiobi, D. O. 2008a. Measures of servicing capacity of boars and their effects on

subsequent fertility in artificially inseminated gilts. Journal of Applied Animal Research 34: 9-12.

Umesiobi, D. O. 2008b.. Supplemental Vitamin E: A requirement for optimizing fecundity rates and litter size in sows. The Philippine Agricultural Scientist 91 (2): 187-194.

Umesiobi, D. O. 2008c . Effects of sexual stimulation of boars on the fertility and fecundity rates in sows. The Philippine Agricultural Scientist 91 (1): 379-385.

Umesiobi, D. O. and Iloeje, M. U. 1999. Effect of sexual teasing and diurnal period of semen collection on reaction time and semen characteristics of Large White boars. J. Sustain. Agric. and Environ. 1(2) 231 - 235.

Umesiobi, D. O., Iloeje, M. U. and Berepubo, N. A. 2002. Artificial insemination in sows using Guelph and two local semen extenders. Nig. J. Anim. Prod. 29(1): 121 - 126.

Umesiobi, D. O., Kalu, U., Ogundu, U., Iloeje, M. U., Anyanwu, D. C., McDowell, L. R. 2004. Fertility studies on two methods of libido maintenance in West African Dwarf rams. J. Anim. Vet. Advances 3(2), 81-84.

Strzeżek, J., Fraser, L., Demianowicz, W., Kordan, W., Wysocki, P., Hollody, D. 2000. Effect of depletion tests (DT) on the composition of boar semen. Theriogenology. 54(6): 949-963.

Acknowledgement Prof. D O Umesiobi Department of Agriculture and Rural development,

Free State (DARD) Department of Agriculture, Fisheries and Forestry

(DAFF) Central University of Technology, Free State (CUT, FS) National Research Foundation (NRF) Grootvlei Prison Farm, Piggery unit