Reproductive performance and milk traits of F1 Romanov ewes

The objective of this study was to evaluate the effect of crossbreeding Awassi and Morkaraman ewes with Romanov sires on litter size and total productivity as reflected by reproductive performance and milk production in the ewes. Twenty-three Romanov × Awassi (RA) and 19 Romanov × Morkaraman (RM) ewes were used. All of the ewes were pregnant at the start of the study, and litter size at birth and at weaning (60 days) were recorded. Milk production was recorded weekly and milk composition was estimated as dry matter and fat percentage. Litter size at birth (RM: 1.89 ± 0.18; RA: 1.62 ± 0.15) and weaning (RM: 1.67 ± 0.20; RA: 1.46 ± 0.17), dam weight at lambing (RM: 50.2 ± 2.37; RA: 44.2 ± 1.98) and total productivity (RM: 29.9 ± 3.05; RA: 24.4 ± 2.54) were not influenced by breed-type. Lactation length and milk yield was relatively but not significantly higher in RA than RM ewes. Dry matter and fat percentage of milk were found to be similar for both breed-types. Results of the present study indicate that crossbreeding of Awassi and Morkaraman ewes with Romanov rams yielded similar performance in F1 ewes. When F1 ewe performance is compared with their pure breed maternal ancestor, it is concluded that reproductive performance is improved by crossbreeding with Romanov.     

Effects of PMSG and ram contact on the reproductive performance of progestagen-treated ewes during breeding and anestrous seasons

The objective of this study was to evaluate the efficacy of combinations of PMSG treatment and ram contact on the reproductive performance of progestagen-treated ewes during three different times of the year, Febraury (early anestrus), July (late anestrus) and October (breeding season). A total of 109 multiparous Dorset ewes was used. Ewes were treated with intravaginal progestagen pessaries for 12 days, injected with 500 IU PMSG at pessary removal and either isolated from rams prior to mating (n = 12, February; n = 12, July; n = 8, October) or exposed to rams during pessary treatment (n = 17, February; n = 12, July; n = 8, October). A third treatment group (n = 18, February; n = 6, July; n = 8, October) received pessaries and ram exposure but no PMSG. An additional treatment of progestagen pessaries alone was included in October (n = 8). There were no differences among treatments in their ability to induce estrus at different times of the year, but incidence of estrus tended (P < 0.10) to be lower for PMSG treatment during the July breeding. During February, the use of pessaries with PMSG treatment increased (P < 0.05) conception and lambing rates, whereas ram contact was without any beneficial effects. The trend was reversed during July breeding, when ram contact increased (P < 0.05) fertility of progestagen-treated ewes compared with other treatment combinations. Pessaries alone were sufficient to attain acceptable levels of fertility and fecundity in October.     

Reproductive performance of repeat breeders in dairy herds

The objectives were to characterize repeat breeding in dairy cows, including reproductive performance and risk factors. Data from 613 Holstein Friesian cows in nine dairy herds across Japan were enrolled. A repeat breeder was defined as a cow that did not become pregnant after three inseminations, despite no clinically detectable reproductive disorders. In contrast, cows that became pregnant within three inseminations were considered to have normal fertility. Of the 613 cows, 87.3% eventually became pregnant after repeated AI (maximum calving to conception interval was 435 d). Mean (±SEM) first AI conception rate, days in milk at first AI, calving to conception interval and service per conception were 38.3%, 82 ± 2 d, 125 ± 3 d, and 2.0 ± 0.1 times, respectively. Normal fertility cows (n = 479) required only 114 ± 3 d to conceive and 1.7 ± 0.1 inseminations per pregnancy, whereas repeat breeders (n = 86) required significantly more days to conceive (211 ± 10) and more inseminations per pregnancy (4.7 ± 0.2). Based on survival analysis, it took 94 d after calving for 50% of normal fertility cows to become pregnant, compared to 155 d for repeat breeders. For repeat breeders, 31.4, 50.0, and 58.1% became pregnant within 210, 300, and 435 d after calving, respectively. The risk factors for repeat breeding were parity (relative risk [RR] = 0.809; P = 0.058), resumption of postpartum ovarian cycles (RR = 1.928; P = 0.009), and days in milk at first AI (RR = 0.991; P = 0.039). In conclusion, repeat breeder dairy cows had very poor reproductive performance. Lower parity, abnormal resumption of postpartum ovarian cycles, and shorter days in milk at first AI were risk factors for repeat breeding.     

藏绵羊和小尾寒羊雄性生殖器官组织结构比较

通过比较绵羊(Ovis aries)的两个品种,生活于高海拔(4500 m)地区的藏绵羊与相对低海拔(2080m)地区小尾寒羊雄性生殖器官的组织结构特征,以探讨哺乳动物生殖器官适应高原环境的组织结构基础。采集成年藏绵羊与小尾寒羊的睾丸、附睾、输精管,运用大体解剖、石蜡切片及常规H.E,染色方法,比较二者生殖器官的组织结构差异。结果显示,藏绵羊附睾头和附睾体管腔内的纤毛较长,而附睾尾管腔内的纤毛较短,呈清晰的刷状缘结构,输精管平滑肌细胞较多,固有膜和黏膜层粘连紧密,且形成较明显的不规则皱襞。与小尾寒羊相比,藏绵羊曲细精管的横切面直径、面积和生精上皮的厚度均显著降低(P<0.05);精原细胞和初级精母细胞的直径及面积显著降低(P<0.05),且支持细胞数也显著减少(P<0.05);附睾头、附睾体、附睾尾的管腔内径和外径及纤毛长度均显著减小(P<0.05);附睾体的柱状上皮厚度显著增高(P<0.05),而输精管管腔直径、平滑肌厚度均显著降低(P<0.05)。研究认为,藏绵羊在高海拔低氧环境的长期适应过程中,其生殖器官的组织结构发生了--定的适应性改变,可能与其在高原环境下正常繁殖性能的维持有关。     

广西亚热带主要森林植被气候及水文生态功能规律的研究

1980-1991年对广西亚热带主要森林植被及草坡地的气象及水文要素进行定位对比研究表明,郁闭度较大的林分内年均气温及年较差比林外低0.1-0.7℃;但年均相对湿度比林外高0.7-6.7%;林内地面年均温及年较差比林外低2.3-7.8℃,相同层次的土壤年均温及年较差比林外低1.6-4.6℃.林内年均水面蒸发量比林外减少51.3一73.0%.各林分的林冠截留量占降雨量9.9-15.8%;树干茎流量占0.5-3.3%;穿透水量占83.9-88.0%.林地枯落物层的最大蓄水量一般比草地大4-13倍.林地年均地表径流量为0.46-22.31mm,一般比草地减少35.2-93.8%.     

封闭群FMMU白化豚鼠繁殖性能与生长发育的初步观察

对本室培育的封闭群ＦＭＭＵ白化豚鼠的繁殖性能和生长发育情况进行初步观察,结果表明：ＦＭＭＵ白化豚鼠系三色豚鼠的变异株（种）,由于严格采用循环交配的封闭群繁育方法,其产仔数、泌乳力、哺乳期增重等繁殖性能和生长发育指标仍维持较高水平,和三色豚鼠相接近。有关繁殖性能指标为：胎间隔８．６７±１７．４／ｄ、窝产仔数２．８９±０．６６／只、初生个体重８６．３９±１０．１７／ｇ,泌乳力４０２．１±４８．３２／ｇ、离乳数为２．６８±０．４１,离乳率为９０．７１±１２．７１％,离乳个体重为１７８．６５±２６．６８／ｇ。３、９、１５、２０日龄豚鼠个体重分别为８８．７６±１０．８１／ｇ、１２３．１８±１２．５５／ｇ、１６３．４１±２１．１３／ｇ、１７５．３６±２２．１７／ｇ;雌性豚鼠个体重分别为９０．３７±１３．７２／ｇ、１３０．７４±２２．１８／ｇ、１６９．７９±２７．８２／ｇ、１７９．９８±２８．１２／ｇ。     

Lactation influences the serum level of leptin and growth hormone during the daily bathyphase in ewes

The aim of the study was to investigate the influence of early lactation on leptin and growth hormone (GH) during bathyphase. Forty lactating Sarda ewes were divided into two equal groups on the basis of their milk production levels: HIGH (>1100 g/day) and LOW (<900 g/day). From the 5th to the 110th day after lambing, every 15 days, body condition score (BCS) was recorded and milk samples were collected. At the same data point, blood sampling was performed and leptin, GH and, Non-Esterified Fatty Acids (NEFA) were assessed. On milk, fat and proteins were determined. Statistical differences were observed in BCS, leptin, GH, NEFA and fat concentration in milk between the two groups. BCS was lower in high group and decreased from the 20th to the 90th day of lactation. Leptin was higher in low group and increased from the 50th and the 65th day of lactation, in low and high groups, respectively. GH and NEFA were higher in high group and decreased from the mild lactation. In high group, BCS and milk yield were negatively correlated and leptin was negatively correlated with GH and NEFA. In low group, leptin was positively correlated with BCS and negatively correlated with the all studied parameters. GH and NEFA were positively correlated with both groups. In conclusion, milk yield had an effect on the leptin and GH plasma values recorded during their bathyphase.     

The effect of hCG treatment on Day 12 post-mating on ovarian function and reproductive performance of ewes and ewe lambs

The objectives of this study were to determine the effect of a single intramuscular injection of 200 IU hCG (Chorulon) on Day 12 post-mating on ovarian function and subsequent lambing performance in ewes and ewe lambs bred at synchronised oestrus during the breeding season and on the lambing performance of ewes induced to breed during late anoestrus. All animals were mated to rams at synchronised oestrus and on Day 12 post-mating given normal saline or 200 IU hCG.In Experiment 1, laparoscopic results showed that hCG treatment induced accessory corpora lutea in ewes (control = 0/7; hCG = 5/7) but not in ewe lambs (control = 0/7; hCG = 0/7).In Experiment 2, hCG treatment did not improve the lambing rate (control = 50; hCG = 57) or the litter size (control = 1.80; hCG = 1.96) in ewes (control = 100; hCG = 91). However, hCG treatment significantly (P > 0.05) improved the lambing rate (control = 29; hCG = 58; P < 0.05) in ewes conceiving at the first oestrus after treatment. hCG treatment (control = 42; hCG = 42) also failed to improve the lambing rate in ewe lambs (control = 48; hCG = 41).In Experiment 3, hCG treatment had no significant (P > 0.05) effect on the lambing rate (control = 72; hCG = 62) or the litter size (control = 1.59; hCG = 1.58) in ewes (control = 111; hCG = 115) induced to breed during anoestrus or on ewes returning to oestrus and conceiving after treatment (lambing rate: control = 86; hCG = 72; litter size: control = 1.44; hCG = 1.35). In conclusion, the data obtained in this study suggest that during the breeding season hCG may, by stimulating ovarian function, improve embryo survival in ewes conceiving at the first post-treatment oestrus. This effect, however was not observed in ewe lambs.     

Reproductive performance and milk yield in Awassi ewes following crossbreeding

The objective of this study was to evaluate the effect of crossbreeding Awassi ewes with either Charollais or Romanov sires, on pre-weaning lamb production as reflected by reproductive performance and milk production in the ewes. Two hundred and five, 3- to 6-year-old multiparous ewes of three breeds were allocated to three groups [Awassi (A; n = 56), F₁ Romanov × Awassi (RA; n = 78) and F₁ Charollais × Awassi (CA; n = 71)]. Upon lambing, ewes and their offspring were placed in a large pen in which they remained until the end of the trial. Body weight (BW) and body condition score (BCS) of the ewes and the BW of the lambs were recorded weekly from birth to weaning at 70 days of age. Milk production was recorded weekly from parturition to weaning. Pregnancy rates were not influenced by breed-type. Multiple births and the fecundity of ewes were greater (P < 0.05) in the RA group, compared to the A and CA groups—while the weaning percentage was similar between the breeds. Lamb birth and weaning weights were similar, while the kg lamb born per kg ewe lambed was greater (P < 0.05) in the RA group, compared to the CA group. The CA ewes recorded a higher BW (P < 0.01) and BCS (P < 0.01) than the other breed groups. Awassi ewes produced more milk (P < 0.01) throughout the observation period. Milk ash percentage was higher (P < 0.05) in the CA group, while the percentage of crude protein and dry matter was similar for the different groups. Results of the present study indicate that crossbreeding of Awassi ewes with Charollais and Romanov breeds decreased milk production in the progeny, without affecting lamb growth. The crossbreeding of Awassi with Charollais resulted in improved BW and BCS, while the crossbreeding of Awassi ewes with Romanov resulted in improved reproductive performance of the crossbreds. Crossbreeding Awassi ewes with exotic rams can thus be conducted to increase the number of lambs produced per ewe.     

早期断奶对犊牛生产性能和母牦牛繁殖性能的影响

本试验旨在研究早期断奶对犊牛生产性能和母牦牛繁殖性能的影响。试验组采取"全哺乳+早期诱饲+补饲+放牧+早期断奶"的模式进行饲养,对照组采取传统放牧。实验表明:试验组犊牛5月龄实现早期断奶,体重极显著高于对照组(p<0.01)((53.13±12.34) kg VS (23.44±9.38) kg);试验组犊牛7月龄时体重达71.42 kg,比对照组提高了1.36倍;血液检测分析:与对照组相比,试验组显著提高了牛表皮生长因子(p<0.05);12月龄时体重极显著高于对照组(p<0.01)((87.25±23.43) kg VS (39.51±17.28) kg);当年生犊牦牛实施早期断奶,母牦牛进入下一个繁殖周期,其"一年一胎"比例达68.6%。因此,早期断奶尚未影响犊牦牛生长发育,同时有利于母牦牛年产犊的提高。     

Reproductive performance of partial gonadectomized male African catfish, Clarias gariepinus broodstocks

This study was conducted to evaluate the effect of partial gonadectomy on reproductive performance of male Clarias gariepinus broodstock. Testes from C. gariepinus broodstock were surgically removed; 25% of the testes (Treatment 1), 50% of the testes (Treatment 2), 75% of the testes (Treatment 3), and removal of the sperm from the testes sac using syringe after the abdominal cavity had been cut open (Treatment 4) {control}. The incisions were sutured and the fish kept inside separate concrete tanks for 4 mo. The incisions closed up within 8 to 9 wk of surgery. The postsurgical survival of C. gariepinus was 100%, indicating the efficiency of the surgical procedure. There was no significant difference (P > 0.05) in sperm production, percentage fertilization, hatchability and survival of the larvae using sperm derived from regenerated testes of the partially gonadectomized C. gariepinus and nongonadectomized C. gariepinus. It also reveals that partial gonadectomy could not alter the quality of sperm production of C. gariepinus. Sperm derived from regenerated testes performed effectively for fertilization of eggs. Based on the results of this study, the removal of 75% of testes during partial gonadectomy proved to be the best as the total number of spermatozoa was more than that of other methods and the sperm was able to fertilize more eggs. Hence the removal of 75% of testis during partial gonadectomy of C. gariepinus is recommended based on the results of this study.     

Reproductive performance in female common hamsters

We monitored individual reproductive timing and output in a common hamster population in Vienna over a 3-year period. Animals were live-trapped, weighed, individually marked, and reproductive status was determined at capture. Costs of reproduction were investigated by measuring body condition shortly before hibernation and overwinter survival. Our results indicated that early emerging females had more litters and weaned more offspring per season. Body mass throughout the active season did not differ significantly between females with high and low reproductive output. High reproductive output seemed to affect the duration of the active season. Successful females had a longer postreproduction period before hibernation than less successful ones, probably serving to balance the costs of reproductive effort by extended preparation for hibernation. Also, females that had emerged early in spring and had high reproductive success were more likely to survive the subsequent winter. Hence, we found female common hamsters to vary strongly in maternal investment capacity and to tailor reproductive strategies accordingly.     

圈养小熊猫繁殖行为变化及繁殖行为对策

In order to investigate the change of reproductive behaviors and understand reproductive strategies of both male and female red pandas, one-year behavioral observation was conducted through the focal sampling method in the Chengdu Research Base of Giant Panda Breeding from December 1999 to November 2000. Our results indicated that reproductive behaviors showed significant differences between the estrous and non-estrous seasons. Frequencies of the rubbing anogenital, sniffing and licking marking were much higher in estrus than in non-estrus. Bleating only appeared in the estrus and can be regarded as an estrous indicator.The result also demonstrated that both male and females applied different reproductive behavioral strategies. Frequencies of activity, rubbing anogenital, licking and sniffing marking, and bleat were much higher in the male than in the female. However, those of resting and investigating were much lower in the male than in the female. This indicated that the male was more active than the female during the estrus and might imply that the male acts mainly as an estrous message sender, and the female as a message receiver in the estrous season.     

BMP-15基因外显子Ⅰ在三种绵羊中的多态性及与繁殖力相关性分析

为研究绵羊繁殖力与绵羊BMP-15 (bone morphogenetic protein 15)基因的多态位点关系,并寻找调控绵羊繁殖力的分子标记,以甘肃高山细毛羊、蒙古羊、小尾寒羊三种绵羊为研究对象,采用PCR-SSCP技术与DNA碱基测序相结合的方法,检测该基因第一外显子67、92两个位点在上述三个不同品种绵羊中是否存在FecX^H (Q23→Ter)和FecX^I (V31→D)突变,同时根据检测结果与其繁殖力做相关性分析。结果表明,在三种绵羊中既未检测出与Inverdale绵羊相同的FecX^I突变,也未检测出与Romney绵羊相同的FecX^H突变,因此推测BMP-15基因中影响Romney与Inverdale绵羊高繁殖力的突变位点对以上三种绵羊均无显著影响。     

Refractoriness to short and long days determines the end and onset of the breeding season in subtropical goats

The objective was to determine whether refractoriness to short and long days were involved in the end and onset of the breeding season, respectively, in goats adapted to subtropical latitudes. Ovariectomized does given a subcutaneous implant constantly releasing estradiol-l7 β (OVX+E) were used in two experiments. Plasma LH concentrations were determined twice weekly. In Experiment 1, the control group remained in an open-shed pen (natural day length and ambient temperature). Two experimental groups were placed in light-proof buildings (with natural temperature variations). One group was exposed to natural simulated increasing days (winter to spring), whereas the other was exposed to a winter solstice photoperiod (10 h of light) from December 21 to April 28. In Experiment 2, the control group remained under natural day length and ambient temperature. One experimental group was exposed to natural simulated decreasing days (summer to autumn), whereas the other group was exposed to a summer solstice photoperiod (14 h of light) from June 21 to October 20. In Experiment 1, the breeding season was not prolonged in does maintained in the winter solstice day length. Mean dates of decrease in LH secretion (end of the breeding season) did not differ significantly between does exposed to natural (February 3 ± 5 d) or natural simulated photoperiod (January 26 ± 14 d) and those exposed to constant short days of winter solstice (February 4 ± 10 d). In Experiment 2, the onset of the breeding season was not delayed in does maintained in the summer solstice day length. Mean dates of increase in LH secretion (onset of the breeding season) did not differ significantly between does exposed to natural (September 7 ± 8 d) or natural simulated photoperiod (September 18 ± 10 d) and those exposed to constant long days photoperiod of summer solstice (September 24 ± 4 d). In goats adapted to a subtropical environment, we concluded that: 1) the end of breeding season was due to refractoriness to short days, and not the inhibitory effect of increasing day length; and 2) the onset of the breeding season was due to refractoriness to long days, and not a stimulatory effect of decreasing day length.     

Effect of superovulation on maternal serum progesterone concentration, uterine and fetal weights at weeks 7 and 15 of pregnancy in Javanese Thin-Tail ewes

Twenty-one pregnant ewe lambs (nine superovulated and 12 non-superovulated) were used to study the effects of superovulation (injecting 700 IU PMSG at the end of diestrus) on maternal serum progesterone concentrations, uterine and fetal weights at weeks 7 and 15 of pregnancy. In the ewes sacrificed at week 7 of pregnancy, superovulation increased the mean number of corpora lutea (P<0.01), fetuses (P<0.01), maternal mean serum progesterone concentration (P<0.01), mean uterine weight (P<0.05), total fetal weight (P<0.01), and average fetal weight (P<0.01) by 133%, 69%, 354%, 66%, 150% and 40%, respectively, when compared to non-superovulated ewes. In the ewes sacrificed at week 15 of pregnancy, superovulation increased the number of corpora lutea (P<0.01), fetuses (P<0.05), maternal serum progesterone concentration (P<0.01), uterine weight (P<0.05), total fetal weight (P>0.05), and average fetal weight (P<0.05) by 207%, 20%, 84%, 37%, 29% and 24%, respectively, compared to those non-superovulated ewes. It was concluded that the increased number of corpora lutea and, therefore, their hormonal secretions by superovulation could increase uterine and fetal growth and development.     

小型哺乳动物的繁殖投入与繁殖成功率

动物的繁殖活动关系到整个种群的生存与灭绝, 繁殖投入和繁殖成功率是繁殖生态学研究的重要内容。从繁殖投入的划分入手, 综述了小型哺乳动物的繁殖投入和繁殖成功率之间的关系及其影响因素、分子生物学技术在繁殖生态学中的应用等, 阐述了小型哺乳动物能够根据自身的状态调整每次繁殖活动中的时间投入和能量分配, 采取不同的繁殖对策。这些繁殖对策是长期自然选择的结果, 其目的都是为了最大限度地提高自身的适合度。并且指出分子生物学技术在繁殖生态学中的应用将大大加快这一研究领域的快速发展。     

A note on ram preference by oestrous ewes: Influence of rams’ age and sexual performance

Ewes in oestrus, besides being receptive to rams, develop an active search for them. We performed two experiments to determine if oestrous ewes prefer: (1) high or low sexual-performance rams, and (2) 2-year-old or aged (>8-years-old) rams. In the first experiment, the preference of ewes for rams with high or low sexual performances was compared in 16 tests. In the second experiment, 17 tests were performed comparing ewes’ preference for aged rams (>8-years-old) or young rams (2-years-old). In each test, two rams were tied at equal distances from the point of entrance of the ewe, with a maximum mobility for each ram of 2 m. The first approach to a ram, the quantity of approaches toward each ram (less than one body length), and the total time that the ewe remained near each ram were registered during 5 min. Oestrous ewes did not display any preference according to sexual performance of rams, but spent significantly more time (P = 0.02), and did it in more tests (P = 0.025), with young than with aged rams. Ewes also tended to approach first (P = 0.07), and more times in more tests (P = 0.06), to young than to aged rams. We conclude that ram's sexual performance seems not to influence oestrous ewes preference, and that ewes’ prefer young (2-years-old) rather than aged rams (>8-years-old).     

Reproductive and productive performance of rabbit does submitted to an oral glucose supplementation

In order to investigate the effect of different levels of oral glucose supplementation and/or reproductive method on productive and reproductive performance of New Zealand White (NZW) doe rabbits in the tropic, 36 bucks and 120 doe NZW rabbits were equally divided among four treatment groups (n = 9 bucks + 30 does). The treatments consisted of supplementing drinking water with 0 (control), 2.5, 5 and 10 g glucose/l, respectively. To study the effect of reproduction method (natural v. artificial), each group was divided into two sub-groups (naturally mated and artificially inseminated) with the same bucks of the same treatment group. Glucose supplementation at 5 or 10 g/l of water increased (P < 0.01) litter weight at birth and at weaning, and litter weight gain during the 4 weeks. However, glucose supplementation at 2.5 or 5.0 g/l water decreased (P < 0.01) feed consumption from 7 to 14 days after delivery. Glucose supplementation at 2.5 g/l water did not affect productive and reproductive performance of rabbits. Artificially inseminated does had higher daily litter weight gain between 21 and 28 days post partum. Artificially inseminated group had better milk conversion during the 1st and 4th week as compared to naturally mated groups. Compared with the control group, the economic efficiency and performance index of NZW rabbits was significantly improved by 5 g glucose supplementation under tropic condition.     

亚热带平原绵羊的高温应激反应

对考湖杂种羊在夏季高温下的应激反应作了一些生理生化测试分析。环境温度逐渐增高时,绵羊的体温、心率、呼吸均有不同程度的增加,其中呼吸、心率增加到一定的程度后,又趋于平缓下降,呈“S”形曲线变化;当环境温度在35℃以下时,皮温高于毛丛温度,绵羊可以蒸发和非蒸发两种方式散热,环境温度接近35℃时,皮温与毛丛温度相等,绵羊只能以蒸发方式散热;高温下血清中K、Na、Cl、胆固醇的浓度显著降低(P<0.01或P<0.05),血清甲状腺激素T_3、T_4浓度显著增加(P<0.01),血清葡萄糖浓度也有所增加。