Effect of Social Rank upon Estrus Induction and Some Reproductive Outcomes in Anestrus Goats Treated With Progesterone + eCG

Abstract

<jats:p>We evaluated the possible role of the social rank [R] (i.e., low—LSR, middle—MSR, or high—HSR) in anestrus goats exposed to a P4 + eCG [D] (i.e., 100 or 350 IU) estrus induction protocol (EIP). Adult, multiparous (two to three lactations), multiracial, dairy-type goats (Alpine–Saanen–Nubian x Criollo goats (n = 70; 25°51′ North) managed under stall-fed conditions were all ultrasound evaluated to confirm anestrus status while the R was determined 30 d prior to the EIP. The variables of estrus induction (EI, %), estrus latency (LAT, h), estrus duration (DUR, h), ovulation (OVU, %), ovulation rate (OR, n), corpus luteum size (CLS, cm), pregnancy (PREG, %), kidding (KIDD, %), and litter size (LS, n) as affected by R, D, and the R × D interaction, were evaluated. While OVU and CLS favored (p &lt; 0.05) HSR (96% and + 1.04 ± 0.07 cm), an increased (p &lt; 0.05) LS occurred in D350 vs. D100 (2.06 ± 0.2 vs. 1.36 ± 0.2); neither R nor D affected (p &gt; 0.05; 38.5%) KIDD. However, EI, LAT, DUR, OR, and PREG were affected by the R × D interaction. The HSR group had the largest (p &lt; 0.05) EI % and DUR h, irrespective of D. The shortest (p &lt; 0.05) LAT occurred in D350, irrespective of R. While the largest (p &lt; 0.05) OR occurred in HSR and MSR within D350, the HSR + D350 group had the largest PREG (p &lt; 0.05). These research outcomes are central to defining out-of-season reproductive strategies designed to attenuate seasonal reproduction in goats.</jats:p>

Early resynchronization protocols for goats: Progestogens can be used prior to an early pregnancy diagnosis without affecting corpus luteum functionality

“…Our current results show that the second P4 device has no effect on luteolysis or early pregnancy from the first FTAI in Saanen goats. Considering mucus production and cervix dilatation, it is possible to say that the majority of does responded to the synchronization protocol, even though not all of them presented signs of oestrous, which can be explained by social ranking (Zuñiga‐Garcia et al., 2020) or a silent heat. However, when analysing the presence of CL on Day 16, it is not possible to say whether those females did not respond at all, or whether the absence of CL was due to early regression.…”

Does Size Matters? Relationships among Social Dominance and Some Morphometric Traits upon Out-of-Season Reproductive Outcomes in Anestrus Dairy Goats Treated with P4 + eCG

“…Certainly, the HSR-goats, which also showed the highest live weight (i.e., heavier) and morphometric values (i.e., larger), would have possessed, not only a higher behavioral dominance, but also a genomic advantage (i.e., PIGY and PRDM6 genes expression) with respect to the LSR goats. Undoubtedly, while social dominance ensures access to the best fodder (i.e., quality and quantity), it also warrants not only greater live weights but upholds enhanced reproductive outcomes [7]. Up to this point, the moderate to high heritability of both growth and morphology traits [56], added to the significant correlations among estrus induction, estrus duration, live weight, thoracic perimeter and diameter, and body length observed in our study, suggest a possible interesting scenario.…”

“…This study was conducted in northern Mexico (Comarca Lagunera; 25 • 51 N, 103 • 16 W, 1190 m), during February and March, the months of the natural anestrous season at this latitude [18,21]. Information regarding the location, environmental conditions, animals, and their management has been previously outlined [7]. Briefly, crossbred-dairy type adult goats (Alpine-Saanen-Nubian x Criollo; n = 70, with 2-3 lactations) managed under stall-fed, intensive conditions, were allocated to two uniform groups concerning live weight (LW, 41.85 ± 1.08 kg) and body condition (BCS, 1.87 ± 0.04; scale from 1 to 4) [32].…”

“…Such behaviors define whether an individual is dominant or subordinate, depending on the result of the confrontations (win or lose) that they continuously develop [1,6]. The social structure that goats make up is called social hierarchy, where we can observe different social ranks (high, medium, and low), and a dominant animal belongs to the high social rank and a subordinate to the low social rank [4,6,7]. In addition, social rank can influence some sexual parameters of the goat, in effect, goats of the high social rank generally present greater reproductive success than goats of lower social ranks [1,[6][7][8].…”

Correlation between estrus onset and ovarian parameters in dairy goats

“…In studies on domestic animals, although dominance is recognized, (10,13) its influence on reproduction remains unclear. Nonetheless, it is well known that small ruminants express social hierarchy behavior in the herd (10) , and social dominance may play an essential role in reproductive management (14) .…”