Vaginal bacterial community composition and concentrations of estradiol at time of artificial insemination in Brangus heifersMessman, Riley, D;Contreras-Correa, Zully, E;Paz, Henry, A;Perry,, George;Lemley, Caleb, O
doi: 10.1093/jas/skaa178pmid: 32515480
Abstract The knowledge surrounding the bovine vaginal microbiota and its implications on fertility and reproductive traits remains incomplete. The objective of the current study was to characterize the bovine vaginal bacterial community and estradiol concentrations at time of artificial insemination (AI). Brangus heifers (n = 78) underwent a 7-day Co-Synch + controlled internal drug release (CIDR) estrus synchronization protocol. At AI, a double guarded uterine culture swab was used to sample the anterior vaginal tract. Immediately after swabbing the vaginal tract, blood samples were collected by coccygeal venipuncture to determine concentrations of estradiol. Heifers were retrospectively classified as pregnant (n = 29) versus non-pregnant (n = 49) between 41-57 days post-AI. Additionally, heifers were classified into low (1.1 to 2.5 pg/ml; n = 21), medium (2.6 to 6.7 pg/ml; n = 30), and high (7.2 to 17.6 pg/ml; n = 27) concentration of estradiol. The vaginal bacterial community composition was determined through sequencing of the V4 region from the 16S rRNA gene using the Illumina Miseq platform. Alpha diversity was compared via ANOVA and beta diversity was compared via PERMANOVA. There were no differences in the Shannon diversity index (alpha diversity; P = 0.336) or Bray-Curtis dissimilarity (beta diversity; P = 0.744) of pregnant versus non-pregnant heifers. Overall bacterial community composition in heifers with high, medium, or low concentrations of estradiol did not differ (P = 0.512). While no overall compositional differences were observed, species level differences were present within pregnancy status and estradiol concentration groups. The implications of these species level differences are unknown, but these differences could alter the vaginal environment thereby influencing fertility and vaginal health. Therefore, species level changes could provide better insight rather than overall microbial composition in relation to an animal’s reproductive health. This content is only available as a PDF. © The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: [email protected]. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
Birth weight affects body protein retention but not nitrogen efficiency in the later life of pigs, van der Peet-Schwering, C M C;Verschuren, L M, G;Hedemann, M, S;Binnendijk, G, P;Jansman, A J, M
doi: 10.1093/jas/skaa180pmid: 32479590
Abstract Exploring factors which might affect nitrogen (N) efficiency in pigs could support the development of precision feeding concepts. Therefore, an experiment was conducted to determine the effects of birth weight (BiW) on N retention, N efficiency and concentrations of metabolites in plasma and urine related to N efficiency in male pigs of 14 weeks of age. Birth weight of the low BiW (LBW) and high BiW (HBW) pigs was 1.11 + 0.14 and 1.79 + 0.12 kg, respectively. Twenty LBW and twenty HBW pigs were individually housed in metabolism cages and were subjected to a N balance study in two sequential periods of 5 d, after a 11-d adaptation period. Pigs were assigned to a protein adequate (A) or protein restricted (R, 70% of A) regime in a change-over design and fed restrictedly 2.8 times the energy requirements for maintenance. Non-targeted metabolomics analyses were performed in urine and blood plasma samples. The N retention in g/d was higher in the HBW than in the LBW pigs (P < 0.001). The N retention in g/(kg BW0.75·d) and N efficiency (= 100% x N retention / N intake), however, were not affected by BiW of the pigs. Moreover, fecal digestibility of N and urinary concentration of N and urea were not affected by BiW of the pigs. The concentration of insulin (P = 0.08) and IGF-1 (P = 0.05) in blood plasma was higher in HBW pigs, whereas the concentration of α-amino N tended to be lower in HBW pigs (P = 0.06). The LBW and HBW pigs could not be discriminated based on the plasma and urinary metabolites retrieved by non-targeted metabolomics. Restricting dietary protein supply decreased N retention (P < 0.001), N efficiency (P = 0.07), fecal N digestibility (P < 0.001), urinary concentration of N and urea (P < 0.001), and concentration of urea (P < 0.001), IGF-1 (P < 0.001), and α-amino N (P < 0.001) in blood plasma. The plasma and urinary metabolites differing between dietary protein regime were mostly amino acids (AA) or their derivatives, metabolites of the tricarboxylic acid cycle, and glucuronidated compounds, almost all being higher in the pigs fed the A regime. This study shows that BiW affects absolute N retention but does not affect N efficiency in growing pigs. Therefore, in precision feeding concepts BiW of pigs should be considered as a factor determining protein deposition capacity but less as a trait determining N efficiency. This content is only available as a PDF. © The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: [email protected]. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
Effects of flush feeding strategy before breeding on reproductive performance of modern replacement gilts: impacts on ovulation rate and litter traitsMallmann, André, L;Arend, Lidia, S;Oliveira, Gabriela, S;Mellagi, Ana P, G;Ulguim, Rafael, R;Bernardi, Mari, L;Bortolozzo, Fernando, P;Knox, Robert, V
doi: 10.1093/jas/skaa186pmid: 32506131
Abstract The effects of two feed levels offered during two estrous cycles before insemination were evaluated on the reproductive performance of gilts. A total of 93 gilts (PIC Hendersonville, TN) were individually housed and manually fed twice a day with 2.1 or 3.6 kg/d of a corn and soybean meal based diet (3.15 Mcal ME per kg and 0.64% standardized ileal digestible lysine), during two estrous cycles before breeding (Cycle 1 – between 1st and 2nd estrus; Cycle 2 – between 2nd and 3rd estrus). Gilts were weighed at the beginning of the experiment, at second and third estrus, and at slaughter (30.2 ± 1.2 d of gestation). Follicles were counted at 2nd estrus, and the embryo-placental units and the corpora lutea were individually counted, measured, and weighed at slaughter. Gilts fed 3.6 kg/d had greater body weight gain during cycle 1 and cycle 2 (P < 0.001; + 9.8 kg and + 10.0 kg, respectively) becoming heavier at 2nd and 3rd estrus (P < 0.001). At 2nd estrus, gilts fed 3.6 kg/d had 1.6 more medium-large follicles (P = 0.074) but no difference in follicle size (P = 0.530) was observed. Gilts fed 3.6 kg/d in cycle 1 or cycle 2 had a greater ovulation rate at 3rd estrus (P < 0.016) than those receiving 2.1 kg/d. Also, 3.6 kg/d in cycle 2 increased early embryo mortality (P = 0.006; 2.3 vs.1.1 dead embryos) and consequently reduced total embryo survival (P = 0.002; 84.6 vs. 90.1%). Gilts fed 3.6 kg/d during cycle 1 had two more total embryos (P < 0.001; 17.2 vs. 15.1) and two more vital embryos on Day 30 (P < 0.001; 16.7 vs. 14.5) in comparison with gilts fed 2.1 kg/d. The coefficient of variation for placental length was greater for gilts fed 3.6 kg/d during cycle 1 (P = 0.003). No further significant effects of feeding levels were observed on embryo and placental traits (P ≥ 0.063). These results suggest that the feeding level during the first cycle after pubertal estrus is crucial to set ovulation rate and potential litter size for breeding at next estrus. However, flush feeding gilts before insemination can negatively impact litter size by reducing embryo survival when breeding at third estrus. This content is only available as a PDF. © The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: [email protected]. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
Sow and piglet traits associated with piglet survival at birth and to weaningGourley, Kiah, M;Calderon, Hilda, I;Woodworth, Jason, C;DeRouchey, Joel, M;Tokach, Mike, D;Dritz, Steve, S;Goodband, Robert, D
doi: 10.1093/jas/skaa187pmid: 32506128
Abstract Understanding the relationship between sow and piglet characteristics that are associated with stillborn rate and pre-weaning mortality is beneficial as litter size continues to increase. Two experiments were previously conducted to evaluate pre-farrowing nutrition regimens on sow and litter characteristics. These two datasets (Exp. 1 and 2) were then used to identify sow and piglet characteristics associated with stillborn rate and piglet survival to weaning. A total of 1,201 sows that gave birth to 19,168 pigs comprised the dataset. The following characteristics were used in multivariate logistic regression analysis for traits associated with stillborn rate or survival to weaning: parity, litter weight, mean piglet birth weight, sow backfat and body weight at d 113 of gestation, gestation length, farrowing duration, litter size, piglet birth order, farrowing assistance, pig to teat ratio, colostrum intake and colostrum yield. Sows within each experiment (herd) were categorized into quartiles for each of the independent variables to quantify the relationship to stillborn rate or survival to weaning. Increased stillborn rate was associated (P < 0.01) with heavier litter weights, lighter piglet birth weights, and larger litters in both experiments. In Exp. 1, increased stillborn rate was associated (P < 0.01) with longer farrowing duration. Increased stillborn rate was associated with sows with less backfat depth at d 113, older parity, or increased farrowing assistance in Exp. 2. In both experiments, pigs born later in the birth order had an increased (P < 0.01) risk of being stillborn. In both experiments, heavier piglet birth weight, greater colostrum intake and lower total born were associated (P < 0.01) with increased survival to weaning. In Exp. 2, pigs born in the first 75% of the litter, or in a litter with lower pig to teat ratio were associated (P < 0.01) with increased survival to weaning. Although the stillborn rate was similar between experiments (6.5 vs. 6.6%), differences in the traits associated with stillborn rate between studies indicate that some associated traits may be herd dependent. However, improving piglet birthweight, placing an emphasis on assisting pigs born later in the birth order and increasing colostrum intake will increase piglet survival from birth to weaning. This content is only available as a PDF. © The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: [email protected]. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)