Reproductive function of Hungarian Mangalica boars: effect of seasons

Seasonal changes in testis volume, testosterone (T) productivity (GnRH test) and semen characteristics of Mangalica boars were studied. The biggest testis volume was measured in autumn and the smallest in winter. Significant differences were demonstrated between autumn-winter (P = 0.012) and autumn-spring (P = 0.015) in testis volume. The highest basic T concentration (Tb) was observed in autumn and the lowest in summer. The provoked T concentration (Tincr) was significantly higher in autumn than in spring (P = 0.0007). A strong correlation was observed between T concentrations and testis volume in spring. The highest ejaculate volume was measured in winter while the lowest in autumn. Significant differences were found in semen concentration as well as in the total number of spermatozoa per ejaculate between seasons. The highest number of abnormal sperm cells was observed in spring while the lowest in summer. It can be concluded that the ejaculate of the Mangalica breed tends to be of lower volume and higher sperm concentration as compared to most pig breeds. Seasonal differences could be observed in testicular measurements, testosterone production capacity and sperm morphological features; however, sperm motility remained constantly high during the study.     

Measurement of semen production rates of boars

Frequency of semen collection was used to determine methods of stabilising epididymal sperm reserves in young boars in order to measure daily sperm output which then allows estimation of daily sperm production. By collecting from boars 3 times a week (Monday, Wednesday and Friday) most boars reached epididymal stabilisation within 4 weeks and the daily sperm output could be calculated from the following 6 collections. A more rapid method of measuring daily sperm output was achieved by collecting from boars 4 or 5 times during one day and daily for the following 4 days. Daily sperm output measured by this method was not found to be significantly different from the method requiring collections over a 6-week period. Frequency of collection had a significant effect on semen characteristics. Collecting 3 times a week resulted in significantly greater volumes, sperm concentration, total number of sperm in the ejaculate and daily sperm output compared with collecting at intervals of 48 h. A collecting frequency of 48 h resulted in significantly greater volumes, sperm concentration and total number of sperm in the ejaculate but not daily sperm output when compared with collecting every 24 h.     

Fluctuation in the concentration of sex steroids and aflatoxin B1 in the seminal plasma of boars and its relation to sperm production

The concentration of testosterone, 17-beta oestradiol and aflatoxin B1 were studied in the semen plasma of 21 boars of four breeds for the period of twelve months. The following spermiological parameters were investigated: semen volume, sperm concentration, percentage of abnormal spermatozoa, and survival of spermatozoa. The fertilizing capacity of ejaculates was evaluated according to the conception rate of sows and gilts after the first insemination, according to the average number of piglets per litter and average number of live-born piglets per litter. The highest aflatoxin B1 residues in sperm were recorded in March to May and were related with aflatoxin concentration in feed ration. The group of boars with fertility disorders had more aflatoxin in their sperm (up to 100 pmol . l-1), lower sperm concentration, lower survival of spermatozoa, and a larger proportion of abnormal spermatozoa. The year season had a significant influence on the concentration of the hormones. The highest average value of testosterone (10.2 +/- 1.28 nmol) was obtained in autumn and lower values were recorded in winter. The changes in 17-beta estradiol concentration were similar to the changes in testosterone content, with the maximum value in November (0.249 nmol X 1(-1]. The boars with reproduction disorders had a significantly lower concentration of 17-beta oestradiol. Significant correlations were found between the concentration of the hormones, semen volume, and sperm concentration. 17-beta oestradiol also had a significant positive correlation to abnormal spermatozoa and to the activity of aspartate aminotransferase.     

Effects of breed and ejaculate volume on sperm morphology and semen parameters of boars

The aim of the study was to determine the relation between the semen quality, frequency of sperm defects, sperm dimensions and shape, and the ejaculate volume of Large White and Landrace boars. A total of 648 ejaculates collected from 31 Large White and 30 Landrace boars were divided into three groups according to the criterion of the ejaculate volume. In this study Landrace boars produced ejaculates with higher volume, sperm concentration, and total numbers of spermatozoa than Large White boars. Landrace boars also showed a lower frequency of sperm with morphological abnormalities (P < 0.05). Landrace boars sperm had larger heads, which were by 0.15 μm longer, and by a larger perimeter and area (P < 0.05). Landrace boar spermatozoa also had a longer flagellum and were generally larger and by 2.07 μm longer than Large White boar sperm (P < 0.05). Significant differences were also found in the shape of sperm of the two breeds (P < 0.05). Landrace boars sperm had more elongated heads, and the ratio of head size to flagellum length was lower than in Large White boars sperm (P < 0.05). Sperm from ejaculates with low volume had a shorter flagellum and a greater head length/flagellum length ratio than sperm from medium- and high-volume ejaculates (P < 0.05).     

不同品种、月份、月龄及采精间隔对猪精液品质的影响

为研究不同品种、采精月份、采精月龄和采精间隔等因素对加系公猪精液品质的影响,以及品种、初次采精周龄对精液质量稳定性的影响,本研究以江西某种公猪站79头加系大白猪、长白猪、杜洛克猪种公猪为试验群体,收集2018年12月至2020年12月3 921条精液采集与精液质量数据,通过混合线性模型与方差分析探究各因素对精液量、精液密度、精子活力、总精子数及其稳定性的影响。结果显示,从不同品种对精液质量的影响来看,长白猪精液量和总精子数均高于大白猪、杜洛克猪,但杜洛克猪精液密度高于长白猪、大白猪,杜洛克猪精子活力最低;从不同月份来看,1~3月采精精液密度最高,4~6月采精精子活力最高,10~12月采精精液量和总精子数最高,精液量呈现秋冬多、春夏少的季节变化规律。公猪不同月龄采精,精液质量指标也存在差异,月龄越小精液量越低,但精液密度偏高,精子活力相对较好,在19~24月龄黄金期总精子数最高。不同采精间隔对精液质量有较大影响,采精间隔越长,精液量、精液密度、精子活力和总精子数相对较好,采精间隔为5 d时综合性能最佳,但过长的采精间隔导致精子活力降低。品种影响总精子数稳定性,长白猪、大白猪总精子数稳定性显著优于杜洛克猪（P<0.05）。本研究结果表明,品种、采精月份、采精月龄和采精间隔均会影响公猪精液质量,关注这些因素有助于公猪站制定更完善的生产计划,提高公猪利用率。     

Phenotypic Correlations of Testes Size with Semen Traits and the Productive Traits of Young Boars

The aim of this study was to investigate whether there is a relationship of young boar testes size with semen traits and with productive traits. The dimensions (length, width and volume) of each testis and semen traits (semen volume, percentage of sperm with progressive motility, sperm concentration, total number of sperm in semen, percentage of sperm with normal acrosome, percentage of sperm with major and minor morphological defects, osmotic resistance test value and activity of aspartate aminotransferase in seminal plasma) were determined on 120 young boars aged 6 months. At 180 day of age, the boars backfat thickness and leanness (by ultrasonic apparatus) and body weight were also measured. The average daily gain was determined in the period from 70 to 180 days of age of the boars. The results showed that the sperm concentration, total number of sperm in semen and percentage of progressive motile sperm were a significantly positively correlated with width and volume of the left (p ≤ 0.01) and right testis (p ≤ 0.05) and with total volume of both testes (p ≤ 0.01). But the highest values of correlation coefficients were found between the width of the left testis and sperm concentration, total number of sperm in semen and percentage of progressive motile sperm. A correlations of dimensions (length and width) and volume of testes with other semen traits were very low and statistically non‐significant. The volume of testes (left and right testis and total testes) was significantly positively correlated with body weight at 180 days of age and daily gain (p ≤ 0.01), but lower correlation coefficient was between left testis and daily gain (p ≤ 0.05), whereas correlations were low and non‐significant with leanness and backfat thickness.     

Characterization and Evaluation of Semen in Growing Awassi Ram Lambs

This study was conducted to determine when semen can be collected and to characterize and evaluate the semen collected from growing Awassi ram lambs. Semen was collected regularly once a week for 20 months, starting at 11 months of age, from 14 Awassi ram lambs of milk and meat lines that accepted the artificial vagina. After each collection, the semen was evaluated in terms of its appearance, ejaculate volume, progressive motility, spermatozoa concentration and density. There were significant effects (p<0.01) for the age and weight of the lambs on ejaculate volume, progressive motility and spermatozoal concentration, while the types of birth and production line had no significant effects on these characteristics. Ejaculate volume and spermatozoal concentration increased significantly (p<0.01) with age, despite monthly variations. Progressive motility was similar throughout the year. Average values for ejaculate volume, progressive motility and sperm concentration were 1.2±0.5 ml, 75±10% and (4.0±1.6)×10⁹ sperm/ml, respectively. The highest positive and significant correlations were found between the semen characteristics (r = 0.29–0.68). On the other hand, a negative and significant (p<0.01) correlation (r = –0.66) was found between the spermiodensimeter readings and spermatozoal concentration, and the relationship could be represented by a linear equation Y = 7.85 – 0.07X ±0.37, where Y = expected concentration of sperm (units of 10⁹ sperm/ml) and X = spermiodensimeter reading. However the modest correlation coefficient indicates that the accuracy and precision of the resulting predictions will not be high. It was concluded that semen can be collected with a good quality from growing Awassi ram lambs at 11 months of age.     

The effect of exogenous administration of oestrogens on the function of the epididymis and the accessory sex glands in the boar.

Three normal, sexually mature young boars of Swedish Yorkshire breed were treated with daily intramuscular injections of diethylstilboestrol and/or oestradiolbenzoate for a total period of 13–15 weeks. Whole ejaculates were collected on a dummy sow with an artificial vagina twice a week. The ejaculate was examined as regards semen volume, sperm concentration, sperm motility and sperm morphology. The seminal plasma was analysed for Na, K, Cl, Mg, inorganic phosphate, total protein and fructose. Testicles, epididymides and the accessory sex glands were obtained at slaughter. Material from epididymal segments A, B, D_b, F_a and F_b was collected and examined for sperm morphology. Spermatocrit, osmotic pressure and plasma concentrations of Na, K, Gl, total protein and GPC were assessed in material from epididymal segment F_a. The sex glands and the accessory sex glands were examined maeroscopically and microscopically.The semen volume, the sperm concentration and consequently the total sperm count per ejaculate showed a gradual increase during the course of the investigation. This is to be expected as the boars used were comparatively young at the beginning of the experiment. These values were all within normal limits for adolescent boars.Taking all the characteristics examined into consideration no conclusive evidence was found that an exogenic administration of oestrogens to intact boars has any influence on the function of the epididymis and the accessory sex glands.     

B‐mode Ultrasound and Grey‐Scale Analysis of the Epididymis in Boars,and the Relationship to Semen Parameters

This study investigated the epididymis of mature boars (n = 10) by means of B‐mode ultrasound and grey‐scale analysis (GSA) for echogenicity (EG) determination using an ultrasound unit HS 1500V, a linear transducer (frequencies 7.5–9.0 MHz), and standardized unit settings. All boars had their epididymal caput, corpus and cauda scanned six times before and after semen collection, respectively, at weekly intervals. Semen was subjected to spermatological examination including volume, total and forward motility, sperm abnormalities, as well as total sperm count and concentration. The caput and corpus both had a homogeneous fine echotexture. The cauda was homogeneous too but had a marbled echotex‐ture. Echogenicity before and after semen collection was caput > corpus > cauda, respectively (p < 0.001). Echogenicity was higher before than after semen collection for all parts of the epididymis, respectively (p < 0.001). Echogenicity of the caput correlated slightly positively with the total sperm count pre‐collection (r = 0.301; p = 0.020) and with ejaculate volume pre‐ and post‐collection (r = 0.302 vs 0.306; p = 0.017 vs 0.019), and slightly negatively with sperm concentration post‐collection (r = ?0.275; p = 0.034). No relationship was found for EG of the corpus and cauda for any of the ejaculate parameters. In conclusion, B‐mode ultrasound and GSA proved feasible for imaging the epididymis in boars. Single relationships between EG and ejaculate parameters were found and deserve further investigation.     

Sperm Production and Sperm Morphology of Swedish Warmblood Stallions

The present study investigated daily sperm output and sperm morphology of fresh semen in eight Swedish Warmblood stallions aged 5–8 years. They were used for artificial insemination, and their fertility during the breeding season of semen collection exceeded 60% per cycle. One ejaculate of semen was collected daily for 10 consecutive days from each stallion. The gel-free volume was measured, and the sperm concentration was assessed with a Bürker chamber. The volume of gel-free fraction was multiplied by the sperm concentration to give the total number of spermatozoa (TSN). Sperm morphology was examined in ejaculates collected on days 2, 5 and 10. An aliquot from each ejaculate was fixed in 1 ml formol–saline immediately after collection and examined under a phase-contrast microscope (magnification 1000×) to assess morphological abnormalities. Furthermore smears were prepared and stained according to Williams (carbolfuchsin–eosin) for a more detailed examination of the sperm heads under a light microscope (magnification 1000×). Analysis of variance was applied to data. Total spermatozoa number decreased progressively during the first 8 days of collection, and daily sperm output (DSO) was calculated as mean TSN of collections on days 8–10, being 6.4 × 10⁹ spermatozoa. The overall percentages of morphologically normal spermatozoa in ejaculates collected on days 2, 5 and 10 were above 70%, being significantly lower in ejaculate 2 (68.6%) compared with ejaculates 5 and 10 (72.9% respectively 75.3%).     

Estimation of Genetic Parameters and Analysis of Season Effects and Age Effects for Semen Traits in Landrace Boars

The purpose of this study was to estimate the genetic parameters of semen traits of Landrace boars in South China and to analyze the influence of the age and season of semen collection on semen traits, so as to provide theoretical basis for formulating reasonable boar breeding program. The Asreml-R was used to analyze the 107 221 semen data of 1 605 Landrace boars from 2 AI stations in Southern China, the single-trait repeatability animal model was used to estimate the variance components, heritability and repeatability of each semen traits, two-trait repeatability animal model was used to estimate genetic correlation and phenotypic correlation of semen volume, semen density, sperm motility and percentage of abnormal sperm. The general linear model of R language program was used to analyze the influence of age and season of semen collection on semen traits. The results showed that the semen volume and percentage of abnormal sperm had medium heritability (0.23 and 0.38), and the variation coefficient of percentage of abnormal sperm was 85.42%, while the other traits had low heritability (0.07-0.19). Semen volume-semen density and sperm motility-percentage of abnormal sperm had extremely significantly negative genetic correlation(-0.77 and -0.90, respectively). Semen density-sperm motility showed extremely significantly positive genetic correlation (0.50). The influence of the age of semen collection on semen traits was significant(P<0.05). After boars reached sexual maturity, semen volume showed a significant increase, semen density and percentage of abnormal sperm showed a general decrease, and total sperm number and functional sperm number were significantly higher in the 13-18-month of age group than those in the other groups (P<0.05). The semen density was the highest in spring, and the total sperm number and functional sperm number were significantly higher in autumn and winter than those in spring and summer (P<0.05). In conclusion, the semen volume and percentage of abnormal sperm of Landrace boars can be selected as candidate traits. In the boar production management, boar whose semen production after 36 months of age decline, will be considered to update. Boar semen quality was significantly higher in autumn and winter than those in spring and summer. It is suggested that cooling work should be done in advance in Southern China in summer.     

长白公猪精液性状遗传参数评估及采精月龄和季节因素分析

旨在估计华南地区长白种公猪精液性状遗传参数以及分析公猪采精月龄和季节对精液性状的影响,为合理制定种公猪育种方案提供理论依据。本研究采用Asreml-R对华南地区两个公猪站1 605头长白公猪107 221条精液数据进行统计分析,利用单性状重复力动物模型估计公猪精液各性状的方差组分、遗传力和重复力,利用两性状重复力动物模型对精液体积、精液密度、精子活力和精子畸形率等性状进行遗传相关和表型相关估计;利用R语言程序中的一般线性模型分析采精月龄和季节对精液性状的影响。结果表明,精液体积和精子畸形率属于中等遗传力（0.23和0.38）,其中精子畸形率的变异系数较大,为85.42%,其余性状都为低遗传力（0.07~0.19）;精液体积与精液密度以及精子活力与精子畸形率为极显著遗传负相关（-0.77和-0.90）;精液密度与精子活力呈极显著的遗传正相关（0.50）。采精月龄对精液性状影响显著（P<0.05）,在公猪达到性成熟后,精液体积呈显著上升趋势,精液密度和精子畸形率总体呈下降趋势,精子总数和有效精子数在13~18月龄组显著高于其他组（P<0.05）。在春季精液密度最高,精子总数和有效精子数在秋、冬季显著优于春、夏季（P<0.05）。综上,长白公猪精液体积和精子畸形率具有较大的选育潜力,可作为候选性状进行选择。在公猪生产管理方面,公猪36月龄后精液产量下降,考虑更新淘汰。公猪精液品质在秋、冬季显著优于春、夏季,在中国南方夏季应提前做好降温工作。     

Effect of collection frequency on the semen quality of broiler breeder

1. Seven 35-week-old Hubbard broiler breeder males were subjected to three semen collection frequencies either once every 2 d (48 h), daily (24 h) or twice daily (12 h). 2. Semen characteristics including motility, volume, concentration and sperm numbers per ejaculate were determined for each ejaculate. 3. Sperm motility was unaffected by collection interval, but semen volume was lower at 12 than 24h intervals. Sperm concentration was lower at 12 than 48h intervals. 4. At 24 and 48 h number of sperm per collection (1.7+/-0.2, 1.8+/-0.2 x 10(9)) were higher than at 12 h (1.2+/-0.1 x 10(9)). 5. The number of semen doses over a 6-d period increased linearly as the frequency of collection increased from once every 2 d to twice daily. 6. It is concluded that output was theoretically maximal at twice daily collection, but in practice not all cockerels may be able to maintain full performance with such a demanding regime.     

Effect of season and social environment on testis size and semen quality of the adult Landrace boar

Eight adult Landrace boars were housed for 12 mo in one of two social environments. Socially nonrestricted boars were penned adjacent to and allowed minimal physical contact with ovariectomized gilts hormonally induced into estrus every 2 wk. Socially restricted boars were penned behind solid walls to eliminate visual and physical contact with other pigs. All animals were subjected to natural changes in daylength. Semen was collected weekly; gel-free volume, gel weight, sperm concentration and number per ejaculate, sperm motility (percent and type) and semen pH were determined. Total protein, citric acid contents and alkaline phosphatase activity were measured in seminal plasma. Testis length and width and various body temperature measurements were recorded monthly. Except for percent motile sperm and alkaline phosphatase activity, all semen characteristics varied (P less than .05) with month. The pattern of seasonal change in semen volume was modified by social environment (group X month, P less than .05). Sperm numbers were highest in winter and lowest in spring and summer. Ejaculate protein and citric acid contents were highest in fall and winter; decreases in spring were associated with moderate ambient temperatures and increases in daylength (r = -.80, P less than .05). Testicular length for socially nonrestricted boars was maximum in November through January and minimum in April through July, and did not vary as extensively for socially restricted boars. Scrotal temperature was elevated during periods of high ambient temperature, but not to values detrimental to spermatogenic function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum testosterone concentration during two breeding cycles of turkeys with low and high ejaculate volumes

Serum testosterone, ejaculate volume, sperm concentration, and total sperm per ejaculate were followed from 24 to 80 weeks of age in Large White breeder turkeys. Blood was collected immediately after the weekly semen collection and serum testosterone was determined by radioimmunoassay. Males were classified as low semen producers (LSP; ejaculate volume <.25 ml) or high semen producers (HSP; ejaculate volume >.50 ml). Semen production, which had started in all males at 28 weeks of age, stopped at 57 ± 2.4 and 62 ± 1.6 weeks, and resumed at 72 ± 0.2 and 71 ± 0.6 weeks (mean ± SEM) for LSP and HSP, respectively. Semen production (volume, concentration, and total sperm) of the second cycle was comparable to that of the first cycle. However, serum testosterone ranged from <.05 ng to 6.0 ng per ml and showed considerable variation within and between males with no significant relationship to either age or ejaculate volume.     

Effects of herbal preparation on libido and semen quality in boars

The objective of this study was to investigate the effects of a preparation from herbal extracts (PHE) on libido and semen quality in breeding artificial insemination boars. Ten fertile boars were divided into control and experimental groups according to significant difference of libido. There were no differences in semen quality between groups. Animals were fed a commercial feeding mixture for boars. The feeding mixture for the experimental group was enriched with PHE, which was prepared from Eurycoma longifolia, Tribulus terrestris and Leuzea carthamoides. Duration of the experiment was 10 weeks. Samples of ejaculate were collected weekly. Libido was evaluated according to a scale of 0-5 points. Semen volume, sperm motility, percentage of viable spermatozoa, sperm concentration, morphologically abnormal spermatozoa, daily sperm production and sperm survival were assessed. Amounts of mineral components and free amino acids were analysed in seminal plasma. Significant differences were found in these parameters: libido (4.05 ± 0.22 vs 3.48 ± 0.78; p < 0.001), semen volume (331.75 ± 61.91 vs 263.13 ± 87.17 g; p < 0.001), sperm concentration (386.25 ± 107.95 vs 487.25 ± 165.50 × 10(3) /mm(3); p < 0.01), morphologically abnormal spermatozoa (15.94 ± 11.08 vs 20.88 ± 9.19%; p < 0.001) and Mg concentration (28.36 ± 11.59 vs 20.27 ± 13.93 mm; p < 0.05). The experimental group's libido was increased by 20% in comparison with the beginning of the experiment. Results of this study showed positive effect of PHE on libido and some parameters of boar semen quality.     

Factors influencing boar sperm cryosurvival

Optimal sperm cryopreservation is a prerequisite for the sustainable commercial application of frozen-thawed boar semen for AI. Three experiments were performed to identify factors influencing variability of postthaw sperm survival among 464 boar ejaculates. Sperm-rich ejaculate fractions were cryopre-served using a standard freezing-thawing procedure for 0.5-mL plastic straws and computer-controlled freezing equipment. Postthaw sperm motility (assessed with a computer-assisted semen analysis system) and viability (simultaneously probed by flow cytometry analysis after triple-fluorescent stain), evaluated 30 and 150 min postthaw, were used to estimate the success of cryopreservation. In the first experiment, 168 unselected ejaculates (1 ejaculate/boar), from boars of 6 breeds with a wide age range (8 to 48 mo), were cryopreserved over a 12-mo period to evaluate the predictive value of boar (breed and age), semen collection, transport variables (season of ejaculate collection, interval between collections, and ejaculate temperature exposure), initial semen traits, and sperm quality before freezing on sperm survival after freezing-thawing. In Exp. 2, 4 ejaculates from each of 29 boars, preselected according to their initial semen traits and sperm quality before freezing, were collected and frozen over a 6-mo period to evaluate the influence of interboar and intraboar ejaculate variability in the survival of sperm after cryopreservation. In Exp. 3, 12 ejaculates preselected as for Exp. 2, from each of 15 boars with known good sperm cryosurvival, were collected and frozen over a 12-mo period to estimate the sustainability of sperm cryosurvival between ejaculates over time. Boar and semen collection and transport variables were not predictive of sperm cryosurvival among ejaculates. Initial semen traits and sperm quality variables observed before freezing explained 23.2 and 10.9%, respectively, of the variation in postthaw sperm motility and viability. However, more that 70% of total variance observed in postthaw sperm quality variables among ejaculates was explained by boar. This indicates that boar is the most important (P < 0.001) factor explaining the variability among ejaculates in sperm cryosurvival, with most (14 of the 15 boars in Exp. 3) showing consistent (P > 0.05) sperm cryosurvival over time.     

Testicular Measurements and Daily Sperm Output of Tori and Estonian Breed Stallions

Evaluation of testicular measurements and daily sperm output (DSO) yields valuable information for predicting the reproductive capacity of stallions. The present study evaluated testicular measurements (height, length, width and circumference) and DSO of eight Tori and eight Estonian breed stallions. One ejaculate of semen was collected daily for 10 subsequent days from each stallion. The gel‐free volume of semen was measured with a graduated glass cylinder and the sperm concentration was assessed with a Chorjajev chamber. The volume of gel‐free fraction was multiplied by the sperm concentration to give the total number of spermatozoa (TSN). The DSO was calculated as mean TSN of collection on days 8–10 in Tori breed stallions and on days 4–10 in Estonian breed stallions. The DSO of Tori breed stallions was 12.9 × 10⁹ spermatozoa and of Estonian breed stallions 4.5 × 10⁹ spermatozoa (p < 0.001). Testicular measurements (in cm) 1 day after the last semen collection were as follows: left testis– height 7.3, length 10.4 and width 7.3 in Tori breed stallions, and 5.9, 8.1 and 5.9, respectively, in Estonian breed stallions; right testis– height 7.4, length 10.6 and width 7.4 in Tori breed stallions, and 5.5, 7.4 and 5.3, respectively, in Estonian breed stallions. All these testicular measurements were significantly smaller in Estonian than in Tori breed stallions (p < 0.001). Testicular circumference was 45.4 and 35.4 cm in Tori and Estonian breed stallions, respectively (p < 0.001). The testicular circumference was correlated with DSO in both Estonian (p < 0.05) and Tori breed stallions (p = 0.071). The results give us valuable information on the reproductive capacity of Tori and Estonian breed stallions.     

Boar sperm quality in lines of pigs selected for either ovulation rate or uterine capacity

Selection for 11 generations in swine for ovulation rate (OR) or uterine capacity (UC) resulted in significant changes in component traits of litter size. Our objective was to conserve the unique germplasm for the future and to characterize sperm quality as a correlated response to the selection criterion imposed compared with an unselected control line (CO). Boars representing genetic diversity available in all 3 lines were produced in 2 farrowing seasons. Season 1 was born in September 2005 and was sampled for semen characteristics in October 2006. Season 2 was born in March 2006 and was sampled for semen characteristics in February and March 2007. Each boar (n = 60) was collected twice. The sperm-rich fraction was obtained, and volume and concentration of sperm cells were measured to estimate total sperm production. Each ejaculate was extended 1:3 (vol/vol) with Androhep Plus (Minitube, Verona, WI) and was packed for shipping to the National Animal Germplasm Program laboratory for processing into frozen straws. Semen quality was measured by computer-assisted semen analysis at 3 semen processing points: fresh (FR), 24 h after extender added (E), and postthaw (PT). A mixed model ANOVA was applied to the data. Fixed effects of farrowing season, line, and 2-way interactions were fitted. The random effect of boar (n = 60) within farrowing season and line was used to test line differences. Sperm concentration was not different (P = 0.18) among the lines (0.594 × 10(9), 0.691 × 10(9), and 0.676 × 10(9) cells/mL for CO, OR, and UC lines, respectively). However, significance (P = 0.04) was detected for the volume of the sperm-rich fraction, greatest for OR (86.4 mL), intermediate for UC (75.5 mL), and least for CO (70.2 mL). Line differences were thus detected (P = 0.02) for total sperm production per ejaculate, greatest for OR (54.9 × 10(9)), intermediate for UC (48.7 × 10(9)), and least for CO (40.5 × 10(9)). A larger percentage of progressively motile sperm and greater estimates of sperm velocity only at processing point E (P < 0.01) were detected in favor of CO. Estimates of motility, velocity, and other parameters of sperm movement measured on E processing points were positively correlated with the same estimates obtained PT, but the magnitude was low to moderate (r range -0.03 to 0.23). Thus, selection for component traits of female reproduction had a favorable effect on total sperm production of boars.     

Semen characteristics and libido in boars treated repeatedly with PGF2alpha

The objective was to determine the effects of repeated injections of PGF2alpha (Lutalyse; Pfizer) on semen and libido characteristics in terminal-line boars. Semen was collected once weekly from wk 0 to 15 and on four consecutive days during wk 16. Boars received an i.m. injection of 10 mg of PGF2alpha (n = 11) or 2 mL of vehicle (n = 11) immediately before entering the collection room. For the weekly collections, semen volume (220.3 +/- 3.2 mL; mean +/- SE), gel weight (38.7 +/- 0.7 g), total sperm cells (65.4 +/- 1.2 billion), motile sperm cells (67.4 +/- 0.6 %), and sperm velocity (125.9 +/- 1.2 microm/s), were affected by time (P < 0.01) but not by treatment (P > 0.10). Sperm concentration (0.31 +/- 0.01 billion/mL) was not affected (P > 0.10) by time or treatment. The percentage of morphologically normal sperm cells, assessed at wk 16, did not differ (P = 0.39) between groups (80.8 +/- 1.0). Libido was evaluated from wk 0 to 16. There were no effects of treatment or time (P > 0.10) on the period from injection to the start of ejaculation (225.6 +/- 9.1 s). Duration of ejaculation was affected by treatment (P < 0.01; 472.0 +/- 43.1 s and 280.4 +/- 43.1 s, for PGF2alpha-treated and control boars, respectively) and time (P < 0.01). During the intensive collection period (wk 16), semen volume (200.1 +/- 7.1 mL), gel weight (39.2 +/- 1.5 g), sperm concentration (0.19 +/- 0.01 billion/ mL), total sperm cells (39.5 +/- 3.6 billion), motile sperm cells (65.6 +/- 2.2%), and sperm velocity (117.8 +/- 3.7 microm/ s) were affected by time (P < 0.10) but not by treatment (P > 0.10). The period from injection to the start of ejaculation tended to decrease (by 44%) during the intensive collection period in PGF2alpha-treated boars, but not in controls (treatment x time, P = 0.07). Regardless, the period from injection to the start of ejaculation did not differ (P = 0.63) between groups on d 4 of the intensive collection period. Duration of ejaculation was affected by treatment (P < 0.01; 459.1 +/- 24.1 s for PGF22alpha-treated boars vs. 303.1 +/- 24.1 s for controls) but not by time (P > 0.10). Overall, there were no exceptional positive or negative effects of long-term treatment with PGF2alpha on semen characteristics and libido in boars.