Early-weaned sows: altrenogest therapy, estrus, ovulation, and reproductive performance

Santos, José Maurı́cio Gonçalves dos; Wentz, Ivo; Bortolozzo, Fernando Pandolfo; Barioni, W.

doi:10.1016/j.anireprosci.2004.02.011

Cited by 15 publications

(8 citation statements)

References 17 publications

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“…1995). However, some reports show no or negative effects of altrenogest treatments after weaning (Santos et al 2004;Werlang et al 2011). Table 2 summarizes the effects of altrenogest treatments on farrowing rate and litter size.…”

Section: Post-weaning Altrenogest Usementioning

confidence: 99%

Should Weaning be the Start of the Reproductive Cycle in Hyper‐prolific Sows? A Physiological View

Kemp¹,

Soede²

2012

Reprod Domestic Animals

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Contents Normally, sows are in anoestrus during lactation and start their new cycle at the day of weaning. Modern hybrid primiparous sows that suckle large numbers of piglets may lose substantial amounts of body reserves during lactation. This compromises follicle development during lactation. As modern sows have short weaning‐to‐oestrus intervals, these compromised follicles are recruited for ovulation directly after weaning, resulting in lower ovulation rates and lower embryo survival. Postponing or skipping first oestrus after weaning in primiparous sows may help to limit the negative consequences of lactation on subsequent reproduction. Multiparous sows may have very high litter sizes, especially after long lactations as applied in organic sows. These high litter sizes compromise piglet birthweight and survival and subsequent performance. Inducing lactation oestrus in multiparous sows may help to limit litter size and improve piglet survival and performance. This study discusses physiological and reproductive effects of extending the start of a new pregnancy after lactation in primiparous sows and induction of lactation oestrus in multiparous sows. We thereby challenge the view that weaning is an ideal start for the reproductive cycle in modern sows.

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Section: Post-weaning Altrenogest Usementioning

confidence: 99%

Should Weaning be the Start of the Reproductive Cycle in Hyper‐prolific Sows? A Physiological View

Kemp¹,

Soede²

2012

Reprod Domestic Animals

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“…Breeding at second compared with first estrus after weaning ("skip-a-heat") counteracts these effects (Clowes et al, 1994), albeit at the cost of 22 nonproductive days. Alternatively, treatment with progestagens in weaned sows also extends the WEI interval and allows additional time for recovery from lactational catabolism (Santos et al, 2004;Fernández et al, 2005). As reviewed by Kemp et al (2006), progestagen treatment also has been shown to improve the percentage of sows in estrus within 7 d after weaning and to increase ovulation rate, embryonic survival, and subsequent litter size.…”

Section: Introductionmentioning

confidence: 99%

Responses to delayed estrus after weaning in sows using oral progestagen treatment1

Patterson

Wellen

Hahn

et al. 2008

Journal of Animal Science

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Oral progestagen treatment extends the weaning-to-estrus interval (WEI) in weaned sows. Particularly in lower parity sows, this allows recovery from lactational catabolism and improves sow productivity. However, the optimal duration of progestagen treatment in contemporary dam-line sows is unclear. Therefore, sows (n = 749) weaned over consecutive 3-wk periods in June and July and classified as parity 2 and 3 (P2-3); 4, 5, and 6 (P4-6); or parity 7 or higher (P7+) were organized into 2 breeding groups using 1 of 3 strategies: 1) oral progestagen for 2 d before and 12 d after weaning (M14; n = 249); 2) oral progestagen for 2 d before and 5 d after weaning (M7; n = 250); or 3) no progestagen treatment (M0; n = 250). Progestagen (altrenogest) was administered directly into the sow's mouth at a dosage of 6.8 mL (15 mg of altrenogest) daily. Sows were bred using artificial insemination at first detection of estrus after weaning (M0) or altrenogest withdrawal, and every 24 h thereafter, until they no longer exhibited the standing reflex. The WEI for M0 sows was 5.1 +/- 0.1 d. Estrus was recorded sooner (P < 0.001) after withdrawing treatment in M14 than in M7 sows (6.9 +/- 0.1 vs. 7.4 +/- 0.1 d, respectively). More (P < 0.001) M14 sows (88.6 +/- 2.5%) were bred within 10 d of altrenogest withdrawal than M7 (72.8 +/- 2.8%) sows, or within 10 d of weaning in M0 sows (78.8 +/- 2.6%). Reproductive tracts were recovered after slaughter at d 30 or 50 of gestation. For P2-3 sows, ovulation rate (least squares mean +/- 95% confidence interval) in M7 (23.1 +/- 1.0) was greater (P < 0.001) than in M14 (20.7 +/- 1.0) or M0 (19.7 +/- 1.0) sows; no differences were detected in P4-6 and P7+ sows. At d 30, M7 and M14 sows had more (P < 0.01) embryos (16.4 +/- 0.6 and 15.8 +/- 0.4, respectively) than M0 (13.9 +/- 0.5) sows. At d 50 of gestation, number of fetuses in M14 sows (13.6 +/- 0.4) was greater (P < 0.001) than in M0 (11.8 +/- 0.4) and M7 (12.2 +/- 0.3) sows. Use of oral progestagen to delay the return to postweaning estrus for greater than 18 d appears to have potential for improving weaned sow productivity. Given the incidence of high ovulation rates and associated evidence of intrauterine crowding of embryos around d 30 of gestation, the changing dynamics of prenatal loss resulting from longer periods of progestagen treatment may represent an additional production advantage.

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“…A service at second estrus postweaning (delayed mating) increased reportedly PBA at parity 1 and 2 (Le Cozler et al, 1997;Dos Santos et al, 2004), because a higher ovulation rate and higher concentrations of plasma progesterone 10 to 20 h after ovulation were found in first estrus postweaning than those in second estrus in low parity sows (Dyck, 1974;Clowes et al, 1994). However, each reservice increased RI by approximately 45 days at parity 1 and 2.…”

Section: Discussionmentioning

confidence: 78%

Number of services and the reservice intervals in relation to suboptimal reproductive performance in female pigs on commercial farms

Takai

Koketsu

2008

Livestock Science

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Early-weaned sows: altrenogest therapy, estrus, ovulation, and reproductive performance

Cited by 15 publications

References 17 publications

Should Weaning be the Start of the Reproductive Cycle in Hyper‐prolific Sows? A Physiological View

Should Weaning be the Start of the Reproductive Cycle in Hyper‐prolific Sows? A Physiological View

Responses to delayed estrus after weaning in sows using oral progestagen treatment1

Number of services and the reservice intervals in relation to suboptimal reproductive performance in female pigs on commercial farms

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