The effect of semen volume and number of spermatozoa on the fertility of intra-uterine inseminations of pigs

Abstract

Forty-eight sows were inseminated into the uterus with semen (sperm fraction) diluted to 20 ml. with an egg-yolk glucose phosphate (YPG) diluent to contain 10·0 × 109, 1·0 × 109 and 0·1 × 109 spermatozoa. In 24 sows (120 ml. group) insemination of the 20 ml. diluted semen was followed by the intra-uterine insemination of 100 ml. YPG diluent, alone. The success of insemination was judged at autopsy from ova recovered 2-4 days after insemination (Experiment A) or from counts of foetuses present 25 days after insemination (Experiments B and C). In Experiment A the numbers of ‘cleaved’ ova were recorded before fixation: the numbers of ova judged to be ‘fertilised’ were counted in preparations of fixed and stained ova. For 24 sows inseminated with 20 ml. semen alone at the three dosage levels (10·0 × 109, 1·0 × 109 and 0·1 × 109 spermatozoa) the percentages of ‘cleaved’ and ‘fertilised’ ova were 78·5 and 80·9; 83·5 and 81·2; 24·6 and 19·8. For sows inseminated with the same sperm numbers in 20 ml. semen followed by 100 ml. diluent, the percentages were 41·5 and 43·9; 44·2 and 36·2; 24·6 and 6·7. Comparison of numbers of sows with some ova cleaved (or ‘fertilised’) and sows with none cleaved (or ‘fertilised’) showed no significant differences in sow fertility between treatments.Comparison of numbers of sows with all ova cleaved (or ‘fertilised’) and sows with none cleaved (or ‘fertilised’) shows that inseminations with the 20 ml. volume, alone, were of significantly higher fertility than those inseminated with 120 ml.Estimates of fertility based on the examination of unfixed ova differed in 9 sows from estimates based on the examination of fixed and stained ova. In one sow some uncleaved ova were shown to be pronucleate after fixation and staining. Morphologically abnormal ova were identified in 6 sows; most of these abnormal ova showed multinucleate blastomeres. These abnormal ova were found only in sows inseminated with not more than 1·0 × 109 spermatozoa.Counts of the numbers of spermatozoa on fixed ova showed that these tended to decline as the number of spermatozoa inseminated declined. Comparing sows inseminated with the same number of spermatozoa there tended to be fewer spermatozoa on ova from sows inseminated with 120 ml. than on ova from sows inseminated with 20 ml.Of 13 sows in Experiment B inseminated with 20 ml. semen containing 10·0 × 109 spermatozoa, 9 had foetuses present at autopsy 25 days later (11·6 foetuses per sow).Of 17 sows in Experiment C inseminated with 20 ml. semen containing 1·0 × 109 spermatozoa, 7 had foetuses present at autopsy 25 days later (7·1 foetuses per sow).The difference in pregnancy rate for the two groups is not statistically significant.Differences in litter size between the two groups of sows are explainable by differences in ovulation rate between the two groups (group B, 18·2 corpora lutea per sow, group C, 13·4 corpora lutea per sow).

Fertilization in the Pig

“…Note vacuolation of cytoplasm and unvacuolated cortex at periphery. No precise estimate has been made of the errors likely to affect counts but it has been shown (Hancock, 1959) that the method is sufficiently sensitive to detect differences between numbers of spermatozoa on ova from mated and from inseminated sows, and more recently it has been shown (Hancock & Hovell, 1961) that differences between ova from sows inseminated with different numbers of spermatozoa can also be detected. Haematoxylin and eosin.…”

Desempenho reprodutivo de fêmeas suínas inseminadas pela técnica intra-uterina ou tradicional

“…Há mais de 40 anos, estudos já haviam sido efetuados a fim de determinar o número de espermatozóides e o volume da dose inseminante necessários ao bom desempenho reprodutivo com a deposição intra-uterina de sêmen (Hancock, 1959;Hancock & Hovell, 1961). No entanto, a utilização da inseminação artificial em suínos, em grande escala, foi alcançada com a técnica de deposição do sêmen na cerviz.…”

Artificial Insemination in Poultry and the Storage of Semen—A Re-appraisal

“…A minimum of 2, OOO million spermatozoa must be inseminated into a sow to produce successful conception (average litter size per female, ten) and the fertilization of all the eggs occurs over a few hours only (Polge, 1956). Hancock and Hovell (1961) obtained good conception rates in the sow with 1, OOO million spermatozoa if they were placed directly into the uterus in a semen volume of 20 ml.…”