Characterization of summer infertility of sows in large confinement units

Britt, J.H.; Szarek, V.E.; Levis, Donald G.

doi:10.1016/0093-691x(83)90032-8

Cited by 64 publications

(32 citation statements)

References 9 publications

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“…On average, at least $300 million are lost annually in swine alone and billions across the US livestock industry due to heat stress (St-Pierre et al 2003). Longer weaning-to-conception intervals and reduced over-all reproductive performance in sows have been reported in large confinement units during hotter months from June to October in North Carolina (Britt et al 1983). In a 5-year study in France, season was shown to clearly impact the fertility rate of pigs; with the lowest mean fertility of 81.2% occurring during the end of August (end of summer), compared with the highest mean fertility of 86.8% during the end of March (end of winter; Auvigne et al 2010).…”

Section: Summer Infertility: the Problemmentioning

confidence: 99%

Revisiting summer infertility in the pig: could heat stress-induced sperm DNA damage negatively affect early embryo development?

Peña

Gummow

Parker³

et al. 2017

Anim. Prod. Sci.

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Abstract.Temperature is a crucial factor in mammalian spermatogenesis. The scrotum, pampiniform plexus, and cremaster and dartos muscles in mammals are specific adaptations to ensure sperm production in a regulated environment 4À6 C below internal body temperature. However, the limited endogenous antioxidant systems inherent in mammalian spermatozoa compounded by the loss of cytosolic repair mechanisms during spermatogenesis, make the DNA in these cells particularly vulnerable to oxidative damage. Boar sperm is likely to be more susceptible to the effects of heat stress and thus oxidative damage due to the relatively high unsaturated fatty acids in the plasma membrane, low antioxidant capacity in boar seminal plasma, and the boar's non-pendulous scrotum. Heat stress has a significant negative impact on reproductive performance in piggeries, which manifests as summer infertility and results in productivity losses that amount to millions of dollars. This problem is particularly prevalent in tropical and subtropical regions where ambient temperatures rise beyond the animal's zone of thermal comfort. Based on preliminary studies in the pig and other species, this article discusses whether heat stress could induce sufficient DNA damage in boar sperm to significantly contribute to the high rates of embryo loss and pregnancy failure observed in the sow during summer infertility. Heat stress-induced damage to sperm DNA can lead to disrupted expression of key developmental genes essential for the differentiation of early cell lineages, such as the trophectoderm, and can distort the timely formation of the blastocyst; resulting in a failure of implantation and ultimately pregnancy loss. Confirming such a link would prompt greater emphasis on boar management and strategies to mitigate summer infertility during periods of heat stress.

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Section: Summer Infertility: the Problemmentioning

confidence: 99%

Revisiting summer infertility in the pig: could heat stress-induced sperm DNA damage negatively affect early embryo development?

Peña

Gummow

Parker³

et al. 2017

Anim. Prod. Sci.

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“…Season affects duration of postweaning anoestrus because primiparous sows weaned during late summer or early fall have longer periods of postweaning anoestrus than do primiparous sows weaned during spring (Aumaitre, Dagorn, Legault & Le Denmat, 1976;Hurtgen, Leman & Crabo, 1980;Britt, Szarek & Levis, 1983). This effect of season on postweaning anoestrus may be mediated through seasonal differences in food intake.…”

Section: Introductionmentioning

confidence: 99%

Seasonal differences in function of the hypothalamic--hypophysial--ovarian axis in weaned primiparous sows

Armstrong¹,

Britt²,

Cox³

1986

Reproduction

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Summary. Primiparous sows were fed to appetite during lactations that occurred during winter or summer, and 11\m=.\4\m=+-\ 0\m=.\4 pigs per litter were weaned at 23\m=.\5\ m=+-\ 0\m=.\1 days of age. Sows were slaughtered at 0 or 72 h after weaning or blood samples were collected until 24 h after onset of oestrus. Sows that lactated during summer consumed less food and lost more (P < 0\m=.\05)weight, heartgirth and backfat than those that lactated during winter. Weaning-to-oestrus interval was greater (P < 0\m=.\05) in summer (224 \ m=+-\ 25 h) than in winter (93 \m=+-\ 13 h). Content of GnRH in the hypothalamus and concentrations of LH in the anterior pituitary and serum were lower (P < 0\m=.\05) after weaning in summer than winter. The numbers of visible ovarian follicles < 5 mm in diameter at weaning were lower (P < 0\m=.\05) in summer than in winter. In contrast to LH, FSH concentration in serum was higher (P < 0\m=.\10) in summer than winter, but FSH values in the anterior pituitary were lower (P < 0\m=.\05) in summer than in winter. Post-weaning patterns of secretion of oestradiol and follicular development differed between winter and summer. For example, in some sows weaned during the summer, transient surges of oestradiol occurred repeatedly during 0 to 280 h after weaning without provoking surges of LH. These results indicate that the period of post-weaning anoestrus in summer is prolonged because of altered activity of the hypothalamic\p=n-\ pituitary axis, possibly because of changes in sensitivity to the feedback of oestradiol. Lower feed intake during lactations that occur during summer may predispose the endocrine system to the aberrations.

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“…The effects of the changing photoperiod on gonadotropin secretion are mediated by changes in melatonin secretion from the pineal gland. While there is evidence that changes in gonadotropin production in the pigs are similar to this model (Britt et al 1983), there are no reliable data on melatonin production in pigs. Both photoperiod and ambient temperature change with season and influence the weaning-to-service intervals through direct effects on the hypothalmo-hypophyseal-ovarian axis (Britt et al 1983).…”

Section: Discussionmentioning

confidence: 84%

“…High ambient temperatures may negatively influence the reproductive performance of the sow (Britt et al 1983). In a large Hungarian study, seasonal infertility was manifested by -post-weaning anoestrus, -prolonged weaning to oestrus intervals, -increased embryonic mortality, -increased abortions and stillbirths, -reduced farrowing rates, and -decreased born and weaned litter sizes (Bilkei 1995).…”

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confidence: 99%

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Effect of Gonadotropins during Hot Summer Season Given at Different Times after Weaning on Selected Reproductive Indicators of the Sow

Franek

Bilkei

2008

Acta Vet. Brno

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Franek S.P., G. Bilkei: Effect of Gonadotropins during Hot Summer Season Given at Different Times after Weaning on Selected Reproductive Indicators of the Sow. Acta Vet. Brno 2008, 77: 193-198.The experiment was performed on a large indoor herd during a hot season period in Alföld, Hungary. The post-weaning sows (F1 and F2 of Large White × Landrace mated to Duroc boars (mean parity 3.4 +/-0.7 SD; mean body condition 3.01 +/-0.3 SD, previous lactation length of 28.3 +/-1.5 d) were divided into four groups of similar body condition, lactation length and parity and were treated as follows:Group 1: sows (n = 420) were injected subcutaneously with 400 I.U. of Gonadotropinum sericum (pregnant mare serum gonadotropin, PMSG [eCG]) and 200 I.U. of Gonadotropinum chorionicum (human choriongonadotropin, HCG [hCG]) one day after weaning.Group 2: sows (n = 405) received subcutaneously 4 ml of saline injection one day after weaning.Group 3: sows (n = 425), purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning with PMSG and HCG as the animals in group 1.Group 4: sows (n = 415) purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning as group 2.Sows expressing oestrus, sows ovulating after treatment, treatment to oestrus intervals and follicular sizes were evaluated. The number of sows expressing oestrus, sows ovulating, and treatment to oestrus intervals differed between the groups (group 1 vs. 2: P < 0.05, group 3 vs. 4: P < 0.01). The sows treated with PMSG and HCG on day 7 post-weaning (group 3) had smaller (P < 0.05) follicular diameters compared to the sows that were treated one day after weaning. Group 4 sows had a smaller follicular diameter (3.6 +/-0.6 mm) compared to group 1 (P < 0.001) and 3 (P < 0.01).The present results show that the gonadotropin treatment one day after weaning or in the case of anoestrus 7 days after weaning overrides the negative effects of the hot summer season and effectively prevents seasonal infertility of the breeding sow. Swine, reproduction, seasonal anoestrus, gonadotropin, season, infertilityHigh ambient temperatures may negatively influence the reproductive performance of the sow (Britt et al. 1983). In a large Hungarian study, seasonal infertility was manifested by -post-weaning anoestrus, -prolonged weaning to oestrus intervals, -increased embryonic mortality, -increased abortions and stillbirths, -reduced farrowing rates, and -decreased born and weaned litter sizes (Bilkei 1995).The effects of hot season on weaning-to-oestrus intervals are mediated by ovarian follicular development (Soede et al. 1998). Sows with small follicles (< 4 mm) on day 3 after weaning are more likely to experience anoestrus or delayed oestrus compared to sows with larger follicles (Bracken et al. 2003). High ambient temperature during lactation was associated with suppressed follicular growth during lactation (Lucy et al. 2001).

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Characterization of summer infertility of sows in large confinement units

Cited by 64 publications

References 9 publications

Revisiting summer infertility in the pig: could heat stress-induced sperm DNA damage negatively affect early embryo development?

Revisiting summer infertility in the pig: could heat stress-induced sperm DNA damage negatively affect early embryo development?

Seasonal differences in function of the hypothalamic--hypophysial--ovarian axis in weaned primiparous sows

Effect of Gonadotropins during Hot Summer Season Given at Different Times after Weaning on Selected Reproductive Indicators of the Sow

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