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.     

采精室的建立

本文从公猪的训练到器具的使用,介绍了巴西的一个育种群从人工授精公猪采精着手的实践经验. 在2007年末,巴西南部的Suinosul农场与当地的-个猪肉加工厂签订了-份协议,以保证750头F1代母猪的正常生产,并将22 kg活重的仔猪出售给加工厂,在其它养猪场进行育肥.这一协议给农场带来了重大变化.尽管农场从1978年起即开始饲养种畜出售给其他独立经营的农场,但一直采用自然交配的方式进行繁育.为满足新情况的需要,我们决定对终端公猪采用人工授精(AI)的方法进行配种.     

Factors influencing semen characteristics in boars

Factors influencing semen characteristics in young boars reared in a subtropical environment were studied. Age had only a slight effect on semen volume, but had a significant effect on sperm concentration, total sperm in the ejaculate and daily sperm output (DSO), there being marked increase in boars over 12 months of age compared with younger boars. Boars aged between 8 and 12 months had a DSO of 8.1 +/- 2.6 X 10(9) compared with boars 13 to 15.5 months with a DSO of 14.3 +/- 3.9 X 10(9) and boars aged 16 to 18 months with a DSO of 15.2 +/- 6.2 X 10(9). A highly significant correlation was found between bodyweight and all the semen characteristics examined, the highest correlation being with total number of sperm in the ejaculate. Daily sperm output was not significantly correlated with testicular size as measured by width or length in the live animal. Copulatory behavior had little influence on semen characteristics. Semen characteristics studied were not found to be adversely affected by season. A highly significant correlation between total volume and fluid volume, total volume and gel volume, and total volume and sperm concentration was found, but no correlation was found between total volume and total sperm in the ejaculate. Fluid volume was correlated significantly with gel volume, sperm concentration and total sperm in the ejaculate. A highly significant correlation was found between sperm concentration and total sperm in the ejaculate.     

The frequency of collection and semen production in Muscovy ducks

1. Semen was collected by artificial vagina from 40 Muscovy drakes at frequencies of twice daily; once daily; once every 2 d; and once every 3 d for 24 consecutive days.

2. The total mean semen volume over a 24‐d period increased linearly and significantly from 2.15 to 940 ml as the frequency of collection increased from once every 3 d to twice daily, but the average semen volume per collection decreased linearly and significantly from 1.07 to 0.78 ml.

3. The total number of spermatozoa produced by the drakes increased significantly as the collection frequency increased but became asymptotic at the higher frequencies.

4. Although twice daily collection gave the highest total semen volume, there was little difference between once daily and twice daily collection in the total yield of spermatozoa (10.206 x 10⁹ versus 11.794 x 10⁹). It seems that daily collection was the most efficient for production of spermatozoa for artificial insemination during the period under study.     

Genetic parameters for testosterone production in boars

Data were collected in 1982 through 1989 from 66 sires and 358 Duroc boars. Testosterone production was measured from peripheral blood samples before (PRE) and after (POST) GnRH challenge. Additionally, data were collected on testes length at 168 d (TL168), testes width at 168 d (TW168), testes volume at 168 d (TVOL), birth weight (BWT), average daily gain (ADG), days to 104 kg (DAYS104), and backfat adjusted to 104 kg (FAT). Overall means for these traits were 24.6 ng.ml-1.h-1, 75.7 ng.ml-1.h-1, 12.3 cm, 11.6 cm, 422.0 cm3, 1.5 kg, .5 kg, 189.3 d, and 18.5 mm, respectively. Son-sire regressions were used to calculate genetic parameters. Heritabilities for PRE, POST, TL168, TW168, TVOL, BWT, ADG, DAYS104, and FAT were .37, .26, .33, .34, .33, .21, .42, .35, and 0, respectively. Moderately favorable genetic correlations were obtained for PRE and POST with growth measurements. Large positive genetic correlations were present for both PRE and POST with TL168, TW168, and TVOL, and testes measurements had large positive genetic correlations with growth traits. Selection for testes size or testosterone production should be equally effective. However, it seems that selection for testes size would result in larger changes in measures of growth than selection for testosterone. This study suggests that testes measurements are good predictors of both basal and challenge testosterone levels. Selection for increased testis size or increased testosterone levels would be expected to enhance growth.     

Effect of changing female stimulus on intensive semen collection in young Murciano-granadina male goats

The aim of this research was to study the effect of changing female stimulus on libido and semen characteristics from young Murciano-granadina male goats submitted to intensive semen collection using females not in estrus as teasers. Males were submitted to two different sexual stimulation procedures. In the first procedure, the same doe was used as the female stimulus for three consecutive presentations. In the second, the doe was replaced after the second presentation by a new female. Semen volume, concentration, forward progressive motility, and live spermatozoa were scored. To analyze reaction time (RT), three types of analysis were performed. In the first one, RT was analyzed by multifactor ANOVA, taking as a missing value 300 s when a buck did not ejaculate. In the second, RT also was analyzed by multifactor ANOVA, but data from males that did not ejaculate were removed. In the third, a Cox Survival analysis was carried out by censoring data when a buck did not ejaculate within 5 min of entering the test arena. A decrease in semen volume and sperm concentration in the successive ejaculations was observed, being highly marked in the third ejaculation independent of the stimulation procedure (0.62 vs. 0.38 and 0.43 mL, and 2,828 vs. 2,183 and 2,223 million spermatozoa/mL to the first and third ejaculation respectively; P < 0.05). No significant differences were observed either in forward progressive motility or live sperm rate. Changing the female stimulus in the third presentation had no significant effect on any seminal characteristic. Regarding libido and mounting behavior variables, there was a substantial decrease in RT in the third service when the female was changed (with both types of ANOVA). When censored data were taken into account, the relative risk showed that the probability of a male ejaculating in the third presentation increased almost fourfold when the female was replaced than when the female was the same in all services (P < 0.05). In conclusion, young Murciano-granadina bucks can be used as semen donors because none of the most important semen variables used to reject or accept an ejaculate before freezing process decreased after intensive semen collection. We also recommend changing the female stimulus to make the semen collection procedure more efficient and using survival analysis methodology to analyze time data, mainly when a high rate of censored data are scored.     

不同品种公猪精液品质调查

为了研究品种不同的种公猪的精液品质之间存在的差异,本试验通过对长白、大白、杜洛克等3个品种的成年种公猪的精液品质进行统计学方法分析和比较。结果显示:长白公猪的精子活率最好(75.03%),然后依次是大白(71.62%)、杜洛克(70.36%),长白与大白及杜洛克之间差异显著(P<0.05),但大白与杜洛克之间差异不显著(P>0.05);长白种公猪的精液量(337.60mL)与大白(380.00mL)之间差异不显著(P>0.05),但均与杜洛克(251.74mL)之间差异显著(P<0.05)。三个品种精子活率由高到低依次为长白、大白、杜洛克;平均精液量大小依次为大白、长白、杜洛克,综合评价,长白猪的精液品质最好。     

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.     

Age‐related changes in semen quality characteristics and expectations of reproductive longevity in Duroc boars

Quadratic fitting was used to regress semen characteristics of 1441 samples consisting of 12‐month collection from 58 Duroc boars against animal age varied from 10 to 80 months. Data was divided into two groups of cool (14.0–22.7°C, RH 81.5%) and hot season (22.9–29.9°C, RH 86.6%), to test effects of age, season and their interactions. Results revealed that young boars of around 1 year old could endure the hot season. The endurance gradually diminished as animals grew. In the hot season animals exhibited peak performance at age around 33 month and it remained for 1 month, while cool‐season kept boars could last for 48 months from 16 months old onward. The reproductive longevity should be 51 month in a subtropical environment and it may extend to 70 month if heat stress can be avoided. The estimated total sperm contribution of a Duroc boar would be 1.8 times more when kept below 22°C than in a natural subtropical environment. It is concluded that to maintain Duroc boars as semen donor to at least 4 years of age is feasible in a subtropical environment and boar longevity could reach 6 years old if well kept in a temperate region.     

美国的快速安全采精法

美国重新设计公猪站采精区,目的是可以通过高效、安全的手段使每头公猪生产出大量合格的精液。     

种公牛采精技求要点

应用牛冷冻精液进行人工输精是品种改良和繁育的主要手段,而采集优质的精液生产优质的冻精为其前提条件.笔者根据采精的实践经验,总结以下采精技术要点.     

Infectivity of porcine circovirus type 2 DNA in semen from experimentally-infected boars

Porcine circovirus type 2 (PCV2) is an economically important pathogen. It has been demonstrated that PCV2 DNA can be detected in boar semen by PCR; however, the biological relevance of this is unknown. The objectives of this study were to determine if semen positive for PCV2 DNA is infectious (1) in a swine bioassay, or (2) when used for artificial insemination. For the first objective, 4-week-old pigs were inoculated intraperitoneally with PCV2 DNA-negative (bioassay-control; n = 3), PCV2a DNA-positive (bioassay-PCV2a; n = 3), or PCV2b DNA-positive (bioassay-PCV2b; n = 3) raw semen, or PCV2 live virus (bioassay-positive; n = 3), respectively. Pigs inoculated with PCV2 DNA-positive semen and PCV2 live virus became viremic and developed anti-PCV2 antibodies indicating that the PCV2 DNA present in semen was infectious. For the second objective, three Landrace gilts were inseminated with PCV2 DNA-negative semen (gilts-controls) from experimentally-infected boars, and six gilts were artificially inseminated with semen positive for PCV2a DNA (gilts-PCV2a; n = 3) or PCV2b DNA (gilts-PCV2b; n = 3). Serum samples collected from the gilts in all groups remained negative for anti-PCV2 antibodies for the duration of the experiment. In addition, fetal serum samples from all 105-day-gestation fetuses were negative for anti-PCV2 antibodies or PCV2 DNA. Under the conditions of this study, PCV2 DNA-positive semen was not infectious when used to artificially inseminate gilts; however, it was demonstrated to be infectious in a swine bioassay model and therefore is a potential means of PCV2 transmission amongst swine herds.     

Age-related changes of reproductive hormones in young Meishan boars

Meishan pigs are known for their early sexual maturity. On the other hand, they grow slowly. There is no information currently available about the combination of these two characteristics in Meishan pigs. To study the developmental characteristics of Meishan pigs, the plasma concentrations of LH, FSH, inhibin, testosterone, estradiol-17beta, progesterone and insulin-like growth factor-I (IGF-I) in young Meishan boars were determined using RIA and ELISA. Inhibin decreased with age in weeks, while testosterone and estradiol-17 beta increased. Testosterone increased gradually, and an increase in estradiol-17beta occurred after sexual maturity. IGF-I increased before puberty and subsequently decreased just after puberty like a pubertal IGF-1 surge. FSH, LH and progesterone did not change with age. There was no significant correlation among the hormones. During the experimental period, the Meishan boars showed large individual differences. These differences may depend on the fact that Meishan boar reach maturity at 12 weeks of age and continue to grow thereafter.