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Various prenatal factors including the number of littermates (fraternity size) and exposure to male littermate (fraternity sex ratio) during fetal period have been reported to influence postnatal fertility in the mammals. The present research was conducted to study the association of fraternity size and sex ratio with reproductive performance of nulliparous ewes and does. To this end, data associated with number of littermates, exposure to male littermate, birth weight, age at first pregnancy, as well as litter size, sex ratio of offspring, litter weight, and birth weight of female and male offspring after the first parturition retrieved from the database of sheep (n = 536 Romane and 289 Blanche du Massif Central ewes) and goat (n = 174 Alpine and 267 Saanen does) flocks. Fraternity size was negatively associated with birth weight of ewes and does (P < 0.05). Exposure to male littermate during fetal period was associated with younger age at first pregnancy and larger litter size in the does (P < 0.05), but not in the ewes (P > 0.05). Exposure to male littermate during fetal period was positively associated with the odds of male-biased litters in the ewes and does (P < 0.05). Fraternity size was positively associated with litter weight in the does (P < 0.05), but not in the ewes (P > 0.05). In conclusion, the present study showed that the number and sex of littermates during fetal period could impact postnatal reproduction of ewes and does. In this context, some associations, particularly those related to exposure to male littermate during fetal period, were only observed in does, which implicates that the effect of androgens on developmental programming of reproduction may be species-specific., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to disclose., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Level of dam milk production (DMP) and dam milk fat to protein ratio (DFPR), as an indicator of metabolic status in dairy cows, have been identified to be associated with productive and reproductive performance of the offspring. Yet whether the interaction of DMP by DFPR can be associated with performance of the offspring have not been studied to our knowledge. Therefore, the present study was conducted to investigate the association of the main and interactive effects of DMP and DFPR with offspring's birth weight, survival, milk yield and fertility. To this end, data of birth weight, culling rate, milk yield and reproductive variables of offspring born to lactating dams (n = 14,582) and data associated with DMP and DFPR during 305-day lactation were retrieved. Afterwards, offspring were classified in three categories of DMP, including DMP1 (dams with <10.00 × 10 3  kg of 305-day milk production), DMP2 (dams with ≥10.00 × 10 3  kg and <14.00 × 10 3  kg of 305-day milk production), DMP3 (dams with ≥14.00 × 10 3  kg of 305-day milk production), and three categories of DFPR, including DFPR1 (offspring born to dams with <1.00 FPR), DFPR2 (offspring born to dams with ≥1.00 and < 1.40 FPR) and DFPR3 (offspring born to dams with ≥1.40 FPR). Statistical analysis revealed no association of the interaction effect of DMP by DFPR with investigated variables in the offspring (P > 0.05). However, the main effect of DMP was positively associated with milk yield, but negatively associated with survival, age at first insemination and conception during nulliparity, and transgenerational improvement in milk yield in the offspring (P < 0.05). Moreover, the main effect of DFPR was positively associated with birth weight, survival and first service conception rate during nulliparity, but negatively associated with metabolic status and reproductive performance during primiparity in the offspring (P < 0.05). In conclusion, the present study did not find any interaction effect of DMP by DFPR on productive and reproductive variables in the offspring. This finding implicates the association of DMP with milk production in the offspring was regardless of DFPR. Moreover, this finding implies the association of DFPR with postpartum metabolic status and reproductive performance in the offspring was regardless of DMP., Competing Interests: Declaration of competing interest The authors have no conflict of interest to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Although the association of maternal milk production with developmental programming of offspring has been investigated, there is limited information available on the relationship of maternal milk components with productive and reproductive performance of the offspring. Therefore, the present study was conducted to analyze the association of maternal milk fat and protein percentage and milk fat to protein ratio with birth weight, survival, productive and reproductive performance and AMH concentration in the offspring. In study I, data of birth weight, milk yield and reproductive variables of offspring born to lactating dams (n = 14,582) and data associated with average maternal milk fat percentage (MFP), protein percentage (MPP) and fat to protein ratio (MFPR) during 305-day lactation were retrieved. Afterwards, offspring were classified in various categories of MFP, MPP and MFPR. In study II, blood samples (n = 339) were collected from offspring in various categories of MFP, MPP and MFPR for measurement of serum AMH. Maternal milk fat percentage was positively associated with birth weight and average percentage of milk fat (APMF) and protein (APMP) and milk fat to protein ratio (FPR) during the first lactation, but negatively associated with culling rate during nulliparity in the offspring (P < 0.05). Maternal milk protein percentage was positively associated with birth weight, APMF, APMP, FPR and culling rate, but negatively associated with milk yield and fertility in the offspring (P < 0.05). Maternal FPR was positively associated with APMF and FPR, but negatively associated with culling rate, APMP and fertility in the offspring (P < 0.05). However, concentration of AMH in the offspring was not associated with MFP, MPP and MFPR (P > 0.05). In conclusion, the present study revealed that maternal milk fat and protein percentage and their ratio were associated with birth weight, survival, production and reproduction of the offspring. Yet it was a preliminary research and further studies are required to elucidate the mechanisms underlying these associations., Competing Interests: Declaration of competing interest The authors have no conflict of interest to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Anogenital distance (AGD) is related to fertility in cows, but there is little information on the association of AGD and reproduction in does. Therefore, the present study was conducted to assess the relationship between AGD and reproductive variables in Murciano-Granadina does. AGD was measured as the distance between anus and clitoris and does (n = 578) were divided into two categories of AGD, including short AGD (AGD ≤ median of AGD in studied does; n = 313) and long AGD (AGD > median of AGD in studied does; n = 265). Data of reproductive variables were retrieved from the herd database and were analyzed using multivariable statistical models, in which the potential confounding factors were included. AGD data were not normally distributed (3.78 ± 0.02 cm) and ranged from 2.70 to 5.10 cm. AGD was longer in multiparous and primiparous does than nulliparous does (P < 0.0001), and was positively associated with age and body weight (P < 0.0001). The risk of pregnancy and kidding, litter size, fecundity, proportion of male offspring and birth weight of kids were higher in long AGD does than short AGD does (P < 0.05). But abortion risk did not differ between does with long and short AGD (P > 0.05). In conclusion, the present study revealed that AGD had individual variation among Murciano-Granadina does, and does with long AGD were more fertile and more likely to produce larger, heavier and male-biased litters as compared with does with short AGD., (Copyright © 2022 Elsevier B.V. All rights reserved.)