繁殖母猪乏情的原因与防治

正常情况下，可繁母猪在仔猪断奶后2～7天（经产母猪2～5天，初产母猪3～7天）即可发情配种。然而，生产中许多母猪在仔猪断奶后长期不发情，长者可达2～3个月的时间，其比例可占繁殖母猪的15％左右，个别猪场可达30％以上。     

母猪出现断奶后乏情的原因以及防治

近几年,随着猪群饲养量的增加,饲养者也越来越重视对猪群疾病的防治工作。母猪是猪群中比较重要的群体,直接对猪场的经济效益产生影响,所以平时的饲养工作中,应着重注意母猪群的情况,尤其是断奶后乏情,尽量早发现并且及时采取相应的措施进行防治。现主要分析母猪断奶后乏情的具体原因,然后总结出相应的防治方法。     

高温季节母猪断奶乏情原因分析及防治

高温季节是母猪繁殖障碍高发期,也是母猪淘汰高峰期。母猪乏情是猪场母猪淘汰的首要原因。该文分析了高温季节母猪断奶后乏情的原因,并提出了相应的防治措施,以期为猪场生产提供一定的借鉴和参考。     

经产母猪乏情的原因分析及防制措施

1原因分析 1．1胎次年龄 一般情况下,85％。90％的经产母猪在断奶后的5天内表现发情,但初产母猪只有60％一70％在分娩后1星期内发情。此现象的主要原因可能是后备母猪身体仍在发育中,按体重来讲,没有完全达到体成熟。后备母猪在第1胎哺乳过程中,     

断奶母猪乏情的原因分析及处理办法

通常母猪断奶后 ,一般情况下 4～ 10ｄ发情。若母猪断奶后推迟发情 (经产母猪在仔猪断奶后 2 0～ 3 0ｄ未出现发情症状 )或不发情就称母猪乏情。母猪产后乏情是集约化养猪场普遍存在的繁殖障碍问题 ,是造成优良种猪淘汰的主要原因 ,对猪场的经济效益影响很大。王祖昆等认为 ,目前集约化养猪场中母猪年淘汰率约为 3 0 % ,其中 15 %以上是由于母猪长期不发情而被迫淘汰。而我场母猪断奶后不发情造成淘汰的淘汰率为 2 4.5 % 〔1〕。为此笔者现对本场母猪断奶后不发情的原因进行综合分析。1　母猪断奶后推迟发情或不发情的原因分析1.1　母猪哺乳…     

母猪乏情的防治

母猪乏情是指仔猪断奶后10-15d或长达数月仍不发情者。近年来，乏情母猪数量有不断增多趋势，导致母猪空怀期延长，年产仔数减少，养猪效益下降。所以，必须引起重视。     

母猪断奶后乏情的处理办法

正常情况下母猪断奶后很快就发情,其发情出现的时间平均在断奶后7天,最早的2天,最迟17天。母猪断奶后乏情,又称断奶后推迟发情或不发情,是指经产母猪在仔猪断奶后20天内不能正常自然发情,甚至超过30天还未出现发情征象或母猪经久不出现发情。这是目前母猪普遍存在的一个繁殖障碍问题。     

经产母猪乏情的原因及对策

经产母猪断奶以后的再发情，常因季节、天气、哺乳时间、断奶时母猪的膘情、生殖器官恢复状态等因素的不同，发情的迟早也不同。     

母猪乏情的原因和防治

母猪乏情是繁殖障碍症的重要表现,分为后备母猪乏情和经产母猪乏情。母猪乏情在母猪养殖场普遍存在,给养猪场造成了很大的经济损失。本文就母猪乏情的原因和防治对策作一综述,供广大养殖者在生产中参考。     

Prevention of anestrus in sows after the 1st and 2d parturition

The procedure of prevention of anoestria after the weaning of piglets was verified in 389 experimental and 332 control sows of the Prestice breed. The set of animals under study included 77 experimental and 122 control primiparae, 68 experimental and 71 control secundiparae, and 244 experimental and 139 control multiparae (i.e. sows with three or more parturitions). The experimental sows were treated with 1000 IU of serum gonadotropin ad usum vet.-Bioveta-(PMSG) the first day after the weaning of piglets and with 300 IU of chorion gonadotropin (HCG) in the Praedyn inj. Spofa preparation together with 1 ml of Dirigestran inj. Spofa (40 micrograms LHRH) 72 hours later. Control sows were not treated with hormones. The treated primiparae and secundiparae respectively, had a significantly higher percentage of oestrus onset within 10 days after weaning and lower occurrence of anoestria over 10 days after weaning by 31.25 per cent (P less than 0.001), and 21.36 per cent (P less than 0.02) respectively as compared with untreated controls. In the set of secundiparae, the studied hormonal treatment speeded oestrus onset by a significant (P less than 0.01) shortening of the interval from weaning to the first insemination by 0.79 day and by a more frequent onset of oestrus within only 5 days after weaning of piglets. The values of the other criteria of reproduction studies, i.e. percentage of pregnancies after the first insemination, total number of born piglets and number of liveborn piglets converted per one litter in treated primiparae and secundiparae did not differ significantly (P greater than 0.05) from the control.(ABSTRACT TRUNCATED AT 250 WORDS)     

Potential treatments for anestrus in gilts and sows

Pregnant mares' serum gonadotrophin (400 IU) combined with human chorionic gonadotrophin (200 IU) was administered to anestrous gilts (n=31) and sows (n=20) in commercial herds. Two-thirds of the treated animals were mated successfully within seven days and, although no control animals were included, the response indicated that this hormone combination would be useful in herds with anestrous problems. A second experiment was conducted to evaluate the occurrence of estrus and/or ovulations in prepuberal gilts (n=eight/treatment) following injection with pregnant mares' serum gonadotrophin/human chorionic gonadotrophin or other hormones that might stimulate ovarian activity. The pregnant mares' serum gonadotrophin/human chorionic gonadotrophin combination and follicle-stimulating hormone produced estrus within ten days of injection in at least half of the treated gilts but the response was lower with gonadotrophin-releasing hormone and a prostaglandin analogue. Combinations of human chorionic gonadotrophin with small amounts of estradiol benzoate stimulated estrus and ovulation in most of the treated gilts.     

Effect of fractionated weaning on hormonal patterns and weaning to oestrus interval in primiparous sows

The effect of weaning the 4-5 heaviest piglets in the litter on day 33 of lactation and the remainder 2 days later (fractionated weaning) on plasma levels of prolactin, cortisol, oestradiol-17 beta (E2), progesterone (P4) and LH, as well as on the weaning to oestrus interval in primiparous sows was studied. Twelve crossbred sows were grouped into 6 pairs according to farrowing date and litter size. The litter of 1 sow in each pair (F) was weaned in 2 stages, and the other conventionally weaned at 35 days (C). Blood samples were collected via a permanent jugular vein catheter every 3 h from 9 a m to 9 p m daily throughout the experimental period, and intensively at 15 min intervals for 12 h on the day of first and final weaning and for 6 h on the day after each weaning. All sows were slaughtered following their first post-weaning oestrus and the reproductive organs were macroscopically examined. Lactational oestrus was not observed in any of the sows. Sows from 5 out of 6 pairs showed oestrus within 8 days of weaning and post-mortem examination showed normal ovulation. There was a tendency for the F sows to have a shorter weaning to oestrus interval, as compared with the C sows (5 of 6 pairs, 4.8 days v 5.6 days). The plasma levels of prolactin around weaning were not significantly different between the 2 groups. Within 6 h after final weaning, the prolactin concentrations decreased gradually from 7.6 and 8.7 to 1.6 and 1.7 microgram/l in the control and treatment groups, respectively. The plasma levels of cortisol, showing a diurnal rhythm (with the lowest level at 6 and/or 9 p m), did on no occasion differ between the 2 groups. On the day of final weaning, no diurnal rhythm was observed, with cortisol remaining high at 6 and 9 p m. The plasma levels of E2 and P4 were low until final weaning in both groups. After final weaning the E2 levels rose faster in the F sows than in the C sows, to 44.3 and 34.8 pmol/l, respectively, on day 2 (p less than 0.01). No significant differences in levels of plasma LH and the number of LH pulses were observed between the groups. After final weaning the average and base levels of LH and the number of LH pulse(s) increased significantly.     

Ovarian follicular changes after weaning in sows.

Three experiments investigated ovarian follicular development in sows whose litters were weaned at 28 to 31 d of lactation. Unilateral ovariectomy near the time of weaning was used to assess early follicular characteristics and to identify those sows that would not return to estrus within 10 d after weaning. This allowed segregation of and exclusion from the study those sows that had a prolonged interval from weaning to first estrus. In Exp. 1, 82 and 72% of the large follicles that were marked at 48 or 72 h after weaning (10 sows per time point) were subsequently identified as corpora lutea. In Exp. 2, sows (seven to nine per time point) were unilaterally ovariectomized at 0, 6, 12, 18, 24, or 48 h after weaning, and follicular fluid was evaluated for changes in steroid concentrations. Progesterone concentrations in fluid from medium-sized (4 to 6 mm) follicles increased by 6 h after weaning and then declined through 24 h concomitant with increases in testosterone and estradiol. For Exp. 3, follicular fluid and granulosa cells from individual follicles were obtained from sows (seven to nine per time point) at 0, 6, and 24 h after weaning. In follicular fluid, insulin-like growth factor I (IGF-I) concentrations were not correlated (P greater than .05) with concentrations of progesterone, testosterone, or estradiol, or with granulosa cell production of estradiol during culture in androstenedione-supplemented medium.(ABSTRACT TRUNCATED AT 250 WORDS)     

规模化猪场生产母猪的死亡原因调查与分析

为探究规模化猪场生产母猪的死亡原因,利用某规模化猪场2015—2017年的死亡母猪记录,对月份、胎次、妊娠时间、生产阶段的死亡率进行单因素方差分析和组间差异显著性比较。结果显示,各胎次间的生产母猪死亡率差异均不显著(P>0.05),但3胎次母猪死亡率最高,占17.88%;妊娠期的母猪死亡率最高,死亡率为55.54%,并且对不同妊娠时间的死亡率进行分析发现,105～117 d (围产期)死亡率最高,为21.76%,极显著高于其他妊娠时间(P<0.01),85～94 d母猪死亡率最低,为4.52%;6,7,8,9月份生产母猪的死亡率显著高于5月份(P<0.05),其中6月份死亡率最高,5月份死亡率最低,其他月份之间差异均不显著(P>0.05),对比日均温度图发现6月份温度开始升高。结果表明,母猪不同的胎次、生产阶段、妊娠时间及气温的不同都会影响母猪的死亡率,因此要加强对妊娠期特别是低胎次和妊娠后期母猪的护理,提高猪舍夏季降温系统的效率,减少高温对妊娠母猪的刺激。     

丹系母猪断奶后发情和排卵规律的研究

母猪适时配种是提高受胎率的关键措施之一,而决定配种时间的主要依据是母猪排卵时间。本研究采用B超探测技术对56头不同胎龄的丹系高产母猪发情后的排卵规律进行观测研究。结果发现,母猪断奶后发情至排卵间隔平均为(29.28±8.14)h,排卵持续时间平均是(14.64±4.07)h;母猪断奶至发情间隔为4 d时,母猪发情至排卵间隔和排卵持续时间与其他组差异均显著(P0.05);当断奶至发情天数从2 d增加到5 d,发情至排卵间隔平均减少4.78 h,排卵持续时间平均减少2.39 h;哺乳期小于25 d的母猪断奶到发情间隔及排卵间隔与其他两组母猪均差异显著(P0.05);不同哺乳期的母猪排卵持续时间差异不显著(P0.05);胎次对母猪发情排卵时间存在一定的影响,高胎次母猪比低胎次母猪断奶后发情较迟,排卵持续时间也较长。     

母猪子宫炎的防治

母猪子宫炎是由于子宫粘膜受到刺激或感染后引起的粘液性或化脓性炎症,是生产母猪的一种常见生殖器官疾病。随着养猪业的不断发展,母猪子宫炎发病率不断上升,不但经产母猪发病,未经产的处女母猪也发病,猪场中因子宫炎淘汰的母猪占到年淘汰母猪的一半左右。