Duration Of Lactation Research Articles

Association of lifetime lactation and characteristics of menopause: a longitudinal cohort study

Abstract Background Lactation has many established benefits for women’s long-term health; however, its influence on menopause is less clear. This study investigated the association between lifetime duration of lactation and the timing and type of menopause in midlife women. Methods We analyzed survey data on 19,783 parous women aged 40 to 65 years at enrollment in the Alberta’s Tomorrow Project (2000–2022), a prospective community-based cohort study in Alberta, Canada. Duration of lifetime lactation across all births was categorized as: <1 month (reference group; 19.8% of women), 1–3 months (12.1%), 4–6 months (11.7%), 7–12 months (18.8%), and ≥ 13 months (37.7%). Women were classified as premenopause, natural menopause (age at 1 year after the final menstrual period), surgical menopause (age at bilateral oophorectomy), or indeterminate menopause (age at premenopausal hysterectomy with ovarian preservation). Flexible parametric survival analysis and multinomial logistic regression were used to analyze menopause timing and type, respectively, according to lactation status and controlling for birth year, education, parity, hormonal contraceptive use, and smoking. Results In a dose-response manner, longer lactation was associated with reduced risk of natural menopause before age 50 (for ≥ 13 months of lactation, adjusted hazard ratio at age 45: 0.68, 95% CI 0.59–0.78), surgical menopause before age 55 (age 45: 0.56, 0.50–0.63), and indeterminate menopause before age 50 (age 45: 0.75, 0.69–0.82). Longer lactation was associated with lower odds of surgical (adjusted odds ratio 0.54, 95% CI 0.45–0.66) and indeterminate menopause (0.63, 0.55–0.73), compared to natural menopause. Conclusions Optimizing the timing of natural menopause and reducing risks of early surgical and indeterminate menopause may be novel maternal benefits of breastfeeding.

Analysis of the nutritional composition of Bahraini breed camel (Camelus dromedarius) milk: fatty acid, mineral, phenolic, and antioxidant content

Camels live under extremely arid conditions, yet they can produce more milk than any other animal in the desert ecosystem. They also have a longer lactation duration as well as low nutrition requirements. This study aims to determine the fatty acids profile, minerals, antioxidant activity and total phenols/flavonoids content, in camel milk of the species Camelus dromedarius in Bahrain. Gas chromatography was employed to analyze the fatty acid methyl esters obtained after the extraction of fatty acids. Mineral concentrations were measured by an Inductively Coupled Plasma Optical Emission Spectrometer. Antioxidant measurements included total phenolic content by the Folin-Ciocalteu method, total flavonoid contents by AlCl3 colorimetric method, and total antioxidant activity by the ferric reducing antioxidant power assay. The fatty acids analysis (median(interquartile range) %) showed that the most predominant fatty acids were unsaturated fatty acids (50.40(6.76) %), which were slightly higher than saturated fatty acids (49.60(12.17) %). The most abundant saturated fatty acids were C16:0 (26.73(6.73) %), C18:0 (12.32(4.28) %), and C14:0 (10.55(2.86)%). Monounsaturated fatty acid 18:1n9 was 31.5(5.66) %, and 16:1n7 was 12.75(2.19)%, while the major omega-3 was C18:3n3 (3.91(0.71) %). The main omega-6 were C18:2n6 and C18:3n6, accounting for 1.30(0.35) % and 0.94(0.21) %, respectively. The mineral content of camel milk varied, with the presence of macro minerals such as calcium (699.60 mg/L), sodium (855.18 mg/L), magnesium (9.33 mg/L) and potassium (87.09 mg/L). The results showed that camel milk has considerable values of total antioxidant activity (4.75(1.71) mmol/g), total phenolic contents (20.24(11.18) mg GAE/L) and total flavonoid contents (31.74(20.72) mg CE/L). In conclusion, although the (poly)phenol content in camel milk is relatively lower compared to certain plant-based sources, it can represent a good source of antioxidants, in addition to a significant content in unsaturated fatty acids and minerals, further enhancing its nutritional value for human health.

Development of the infant’s microbiota depending on the nature of feeding: A review

Breast milk oligosaccharides (BMOs) are short polymers of simple sugars that are present in high concentrations in a woman’s breast milk (BM). Their content changes fast over time. Genetic factors, the duration of lactation, and environmental factors particularly influence the level of BMOs. BMOs can facilitate the development of the immune system and protect against infectious diseases directly through the interaction of intestinal epithelial cells or indirectly through the modulation of the intestinal microbiota, including stimulating Bifidobacterium growth. Clinical data suggest that adding BMOs to infant formula promotes normal neonatal growth and benefits infant health. Adding 1 or 2 BMOs to infant formulas is safe and brings their composition closer to the BM, allowing the child to develop harmoniously.

Some Yield and Growth Traits of Anatolian Buffaloes and the Effects of First Calving Age and Calving Interval on These Traits

Numerous in-depth studies have described the fertility traits, growth performance and milk yield traits of dairy animals, which are considered indicators of welfare, but there are limited studies examining these traits within the framework of cause-effect relationships, especially in buffaloes. The aim of this study was to determine the changes in some milk, growth and fertility traits of Anatolian buffaloes over the years in some dairy farms where the Buffalo Breeding Project in Public Conditions was implemented in Samsun province and, to investigate the effects of first calving age (FCA) and calving interval (CI) on milk and growth traits. The study was conducted in 27 buffalo farms (3295 buffalo cows and 3317 buffalo calves) located in Bafra district, the region with the highest buffalo population in Samsun province, Türkiye. The data was taken from records previously kept within the scope of the relevant project. The data such as growth characteristics [birth weight (BW), 6th and 12th-mo live weight (LW) values of calves born between 2013-2020] and lactation traits of cows [lactation milk yield (LMY) and lactation duration (LD)] and FCA and CI values were analyzed by analysis of variance. The effect of years on LMY of buffalo cows was found to be significant, and significant positive changes were determined from year to year. In addition, the BW, 6th-mo, and 12th-mo LW values of calves also varied from year to year. As the FCA value of buffaloes increased, the BW, 6th-mo, and 12th-mo LW values of calves and LMY of cows increased. Similarly, CI values affected the BW values of calves (P<0.01), and LMY and LD values increased in parallel with the increase in CI values. Consequently, determining the lactation and growth traits of buffaloes could benefit developing herd management practices that would optimize these performance indicators.

7303 Fasting and Post-load Glucose in Exclusively Breastfeeding Women With Diabetes Risk Factors

Abstract Disclosure: N. Neamonitaki: None. T. Thaweethai: None. D. Pant: None. K. James: None. M.D. Soffer: None. E.A. Rosenberg: None. C.E. Powe: Consulting Fee; Self; Mediflix, Inc. Other; Self; Wolters Kluwer, Up to Date Author. Background: Epidemiologic studies show a reduction in type 2 diabetes incidence with increased lactation duration and intensity, but physiologic mechanisms underlying this association are incompletely characterized. We examined associations between lactation and glycemic physiology in postpartum women. ​ Methods: We conducted a secondary analysis of postpartum participants in a prospective longitudinal cohort study that examined glucose and insulin physiology via serial 2-hr 75-gram oral glucose tolerance tests during pregnancy and postpartum in women with diabetes risk factors. We used linear regression to examine associations between exclusive breastfeeding and fasting glucose, adjusting for age, race/ethnicity, education, body mass index, and number of weeks postpartum. Secondary analyses examined associations with post-load glucose and insulin physiology. Additional analyses considered exclusive breastfeeding compared to exclusive formula feeding and a combination of formula and breastfeeding separately using a categorical exposure variable. Results: Of N=108 women at a mean (SD) of 11 (5.0) weeks postpartum, 56 reported exclusively breastfeeding and 52 reported not exclusively breastfeeding (15 were exclusively formula feeding and 37 were both breast- and formula feeding). Mean (SD) fasting glucose was 83 (7.0) mg/dl in those exclusively breastfeeding and 85 (8.9) mg/dl in those who were not. Fasting glucose was not significantly different in those who were exclusively breastfeeding compared to those who were not after confounder adjustment (β [95% CI] =-1.3 [-4.6, 2.0] mg/dl, P=0.45). The 60- minute post-load glucose was nominally higher in those exclusively breastfeeding, with a mean (SD) of 132 (37.5) mg/dl versus 118 (31.6) mg/dl in those who were not; this difference did not reach statistical significance in the adjusted model (β [95% CI] =12.6 [-2.1, 27] mg/dl, P=0.09). In additional analyses, fasting glucose was not significantly different between women exclusively breastfeeding, exclusively formula feeding, or both breast- and formula feeding; however, post-load glucose at 30 and 60 minutes was higher in the exclusively breastfeeding group compared to the exclusively formula feeding group (30-minute: β [95% CI]= 16 [0.36,32] mg/dl, P=0.045); 60-minute: 26 [4.0,47] mg/dl, P=0.02) in adjusted models. We did not find significant associations with insulin physiology measures. Conclusion: We did not observe lower fasting glucose with exclusive breastfeeding. Instead, glucose levels at 30 and 60 minutes after an oral glucose load were higher in exclusively breastfeeding participants compared to exclusively formula feeding participants. Presentation: 6/2/2024

Effect of Levonorgestrel Implant on Lactation and Infant Growth: A Review

Background: Family Planning is a way to regulate the number of children born and the spacing of pregnancies through information, education, and the use of contraceptives. Postpartum contraception is important to obtain an optimal interpregnancy interval. Postpartum contraception should be initiated early; one of which is Long-Acting Reversible Contraception (LARC). Levonorgestrel can be used to prevent pregnancy because it interferes with ovulation, implantation, and fertilization. Objectives: This study aimed to assess the efficacy and effects of using levonorgestrel implants on breastfeeding and infant growth. Methods: Primary data were in the form of research papers obtained from ScienceDirect, PubMed, and Google Scholar published from the period 2010-2018. The keywords for the searches included: “levonorgestrel”, “levonorgestrel (LNG)-releasing implant”, “levonorgestrel on lactogenesis”, “levonorgestrel on infant growth”, and “levonorgestrel on breastfeeding”, which were used alone or in combination. Results: The 20 selected articles were reviewed based on five identified phrases. Levonorgestrel subdermal implants were shown to be a good choice for women who wanted effective contraception. When used by breastfeeding mothers, levonorgestrel subdermal implants affected neither infant growth (0-1 year of age) nor lactation duration. Conclusions: Levonorgestrel subdermal implants can be effective long-term contraception. These implants are safe for breastfeeding mothers and do not affect infant growth.

PSVII-14 Influence of dam parity and weaning strategy in previous lactation on feedlot performance of Nellore steers

Abstract In tropical beef cattle production systems, the impact of seasonality may be particularly challenging for young cows (primiparous or secondiparous) due to their increased nutritional requirements, encompassing maintenance, growth, gestation, and, in the case of secondiparous cows, lactation. Literature indicates that extending the duration of lactation during gestation is associated with decreased performance of progeny in their postnatal life. Therefore, implementing an early weaning approach can be an effective strategy to alleviate the nutritional demands of lactation in dams, thereby allocating more nutrients for fetal growth. This study aimed to evaluate the effect of early weaning on the feedlot performance of progeny that were in utero at the time of weaning intervention. To create experimental units, secondiparous and multiparous Nellore cows were assigned to one of two weaning strategies, where suckling calves were either; 1) early weaned 150 d (EW); or 2) conventional weaned at 240 d (CW). All calves were weaned at 150 d of lactation in 2022. Three bulls were used: Bull 1: had 13 calves with multiparous cows, had 7 calves with secondiparous cows, comprising 11 EW and 9 CW; Bull 2: had 10 calves with multiparous cows, had 6 calves with secondiparous cows, comprising 6 EW and 10 CW; and Bull 3: had 7 calves with multiparous cows, had 15 calves with secondiparous cows, comprising 11 EW and 11 CW. All cows were managed similarly after weaning, and through parturition, and weaning of subsequent calf, with resulting calves used for the current experiment. Nellore bulls (n = 57) with an initial body weight (BW) of 417.23 ± 9.12 kg and 18 mo of age were allocated to feedlot pens (equipped with Intergado equipment) and fed a common total mixed ration (80:20; concentrate:corn silage) for 97 ± 1.60 d. Bulls were distributed in a randomized complete block in a 2 × 2 factorial arrangement, considering dam weaning strategy in the previous lactation (EW and CW) and dam parity at subsequent calving (multiparous or secondiparous cows, MC and SC, respectively). Data were analyzed using PROC MIXED of SAS 9.4, with a model including the effects of dam weaning strategy, dam parity, and their interaction. Data were considered significant when P values were less than 0.05 and indicated a trend when 0.05 < P ≤ 0.10. There was an interaction between weaning strategy and cow parity, with calves born to SC-CW having reduced initial (P = 0.04) and final BW (P = 0.01) compared with all other groups (Figure 1 and 2). Steers from MC had greater dry matter intake (P = 0.003), and greater biological efficiency (P = 0.03; Table 1). Early weaning improved the final BW of steers born to secondiparous cows, suggesting it could be a strategy to enhance the performance of offspring and the reproductive performance of both secondiparous and multiparous cows.

Fat Content and Energy Calculation in Pasteurized Human Milk: Comparison Between Infrared Analysis and Creamatocrit Method.

Aims: This study aimed to analyze and compare the quantity of energy and fat using the infrared analysis and creamatocrit method in pasteurized human milk (HM) samples. Methods: This cross-sectional study analyzed 1,858 pasteurized human samples from 317 mothers at a single center. Infrared transmission spectrophotometry (Miris, Human Milk Analyser [HMA], Uppsala, Sweden) and the creamatocrit method were used to evaluate the quantity of energy and fat in pasteurized HM samples. Results: The average age of donor mothers was 29.7 ± 5.1 years, and the median duration of lactation was 22 days (interquartile range [IQ]: 7.7-59.2). Full-term births were observed in 196 (95.1%) of the women. The values of energy (difference: +8.96 kcal/dL, 95% CI: 8.52-9.44 kcal/dL; p < 0.001) and fat (difference: +0.40 g/dL, 95% CI: 0.35-0.45 g/dL; p < 0.001) in HM samples obtained by Miris were higher than those by the creamatocrit method. The energy calculated and the fat measured by Miris in the HM samples correlated moderately and directly with the obtained by creamatocrit (fat, r = 0.585; p < 0.001 and energy, r = 0.591; p < 0.01). The linear regression, adjusted for maternal age and lactation time, showed that the energy values calculated by creamatocrit were directly associated with those of Miris (energy kcal/dL = 38.43 + [0.516 × kcal/dL of creamatocrit]). Conclusion: The energy and fat quantity of pasteurized HM samples obtained by the creamatocrit and infrared methods were significantly correlated. However, the values calculated by the creamatocrit method were significantly lower than those by the infrared analyzer.

Influence of non-genetic factors on milk production traits of Gangatiri cattle in Varanasi district of Uttar Pradesh

Research was carried out to examine the influence of non-genetic factors on the milk production characteristics of Gangatiri cows. The study was analyzed from 1254 Gangatiri cows across three tehsils (Pindra, Rajatalab, and Sadar) in Varanasi, Uttar Pradesh. The objective was to ascertain the effects of a number of variables on lactation duration, daily milk production, and lactation milk production including the area, calving season, farmer's economic background, parity, and age at first calving. The overall average means for lactation milk production, daily production of milk, and lactation period were discovered to be 794.6413 kg, 3.956 kg, and 203.8327 days, respectively. The comparison of different parameters indicated that non-genetic factors had a significant impact on milk production. These factors include the region where the survey was conducted, the calving season, the financial context of the farmer, parity or lactation, and first calving age. By analyzing the mean of these parameters, we could determine their impact on milk yield potentials. Given the influence of external variables and differences in the qualities under investigation, the study indicates that significant improvements in the population of Gangatiri cattle can be accomplished by improved management.

Catalase activity in milk and its correlation with milk productivity of cows depending on the duration of lactation

Relevance. The purpose of this work is to study the activity of catalase in the milk of healthy cows with different levels of productivity and to find a correlation between the studied indicators, which is important and relevant in terms of assessing the antioxidant activity of cows’ milk.Methods. The analysis of biochemical parameters of cow’s milk was carried out using the “CombiFoss 7” system (Denmark). The analysis of the total amount of water-soluble antioxidants (TAWSA) was performed on the device “Tsvet-Yauza 01-AA”. Statistical processing of the obtained results was carried out in the Microsoft Excel programs using the “Data Analysis” package, the “R” program (“Psych” package). Milk samples were obtained from black-and-white cows during a whole year.Results. The entire sample of animals (N = 280) is divided into 6 groups by lactation days: 11–30, 31–60, 61–90, 91–120, 121–180 and 180–300 days (groups 1–6). In the first 11–30 days of lactation (group 1), the value of SKVA is significantly higher (17.2 mg/ml) than in the following months. Moreover, the values of the SKVA fluctuate quite strongly. Significant changes were observed for catalase activity: from 1.41 and 1.32 rel. units (groups 1 and 6) to 0.44 rel. units (group 3). During the period of bloating and lactation decline (groups 1 and 6), the highest correlation coefficients between catalase and fat are observed — 0.51 and 0.57, respectively. For all periods of lactation, there is a negative correlation of catalase with true protein. Thus, the activity of catalase in the milk of healthy cows at different periods of lactation was studied and correlations between the studied indicators were found.

Evaluación económica de un esquema de alimentación complementaria continua en cabras locales en pastoreo

Objective. To evaluate the economic viability of incorporating a long term-supplementary feeding scheme in grazing local goats from the last third of gestation and throughout lactation. Materials and methods. Twenty-four local goats were utilized: control group (CG, n=12) and supplemented group (SG; n=12). Daily milk production (DMP) was recorded in goats, per lactation (MPLT), and per lactation stage [early (MPEL) middle (MPML), and late lactation (MPLL)], duration of lactation (DL; days), final live weight (FLW), and final body condition (FBC). In kids, birth weight (BW), weight at sale (WS), age at sale (AS), and mortality rate were recorded. The economic analysis considered the costs of daily supplementation, labor for handling and care of the animals, and sale prices of milk and kids. Results. The best productive behavior and the highest incomes were obtained in SG (p&lt;0.05) for all variables, except AS and mortality rate. The highest values in CG (p&lt;0.05) were obtained in AS and economic profit in almost all the considered variables, Except in MPEL. Positive profits were obtained in SG in early and middle lactation, and negative in late lactation for SG, but with higher FBC. Conclusions. A long-term supplementary feeding is economically viable to increase income and profits from kids and milk sales and improves the body condition of the dams, which will benefit the productivity of the herd.

Cumulative costs of reproduction in a long-lived ungulate

Abstract Cumulative costs of reproduction are predicted by life-history theories of aging, but empirical support for cumulative costs of reproduction in ungulates is limited. Examinations of the relationship between previous reproductive effort and future reproductive output are often limited to successive years. We analyzed pregnancy status, lactation duration, and age class of Elk (Cervus canadensis) in Utah, United States, from 2019 to 2022 to better understand the relationship between previous reproductive effort and future reproductive output, particularly in nonsuccessive years. Pregnancy status 1 year prior, pregnancy status 2 years prior, and age had no effect on the likelihood of pregnancy in Elk. However, lactation duration 1 year prior and lactation duration 2 years prior had a negative effect on the likelihood of pregnancy. The best-fitting model to explain the relationship between pregnancy status and previous lactation was the positive interaction between lactation duration 1 year prior and lactation duration 2 years prior. The results of our study suggest long-lasting (i.e., multiple-year), cumulative costs of reproduction can influence reproductive output in female Elk, but differences in individual quality may have an even greater influence. High-quality individuals may be able to override the costs of reproduction and minimize reproductive trade-offs.

Factors associated with the productive longevity of sows in commercial breeding herds

Abstract. Maximizing sows' productive longevity (PL) represents a significant challenge faced by the swine industry, as the growing increase in the removal rate of sows, mainly young sows, directly impacts the system's economy. In addition, there are ethical concerns associated with animal welfare issues due to the low PL of sows. The objective of this study was to identify and evaluate the risk factors influencing the removal of sows from commercial swine production systems. The variable of interest was the PL of sows. The PL was modeled using Cox regression analysis to identify the factors that affected this variable. The factor with the greatest contribution to PL was sow type (ST), followed by the return to estrus percentage (REP), herd size (HS), season, lactation duration, weaning–estrus interval (WEI), piglets born alive, mummy percentage, and total piglets born. The removal risk was higher for hyperprolific sows than for normal sows. According to the nonproductive day (NPD) variable (an indicator that considers REP and WEI in its calculation), sows with more than 60 nonproductive days per year are at higher risk of elimination. The risk of removal was higher for sows from large herds than for sows from medium or small herds. The PL of sows within a herd is determined by the type of sow and the sows' association with environmental disturbances, including climatic factors (artificial climate control), management practices (human resources), and economic resources (size and infrastructure).

1242-P: Effect of Intensity and Duration of Lactation on Postpartum Adiponectin after Gestational Diabetes

1242-P: Effect of Intensity and Duration of Lactation on Postpartum Adiponectin after Gestational Diabetes

Estimation of economic losses due to leptospirosis in dairy cattle

There are few studies that effectively quantify the economic losses resulting from problems caused by leptospirosis in naturally infected dairy cattle. Given this gap, the objective of this study was to propose and apply a method to quantify the economic losses resulting from productive and reproductive problems in a commercial dairy herd naturally infected by Leptospira spp. For this study, the zootechnical and economic indicators at a property with Jersey cattle were analyzed during the period from 2014 to 2017. The leptospirosis outbreak occurred in 2014, and the therapeutic approach was carried out between 2015 and 2017, with the latter considered the year of control of the outbreak. The adopted integrated control strategy consisted of dividing the herd according to the serological results obtained through the microscopic agglutination test, the treatment of reagents with streptomycin, and vaccination against leptospirosis of non-reagent heifers and cows. The method used to evaluate the economic indicators of the property was the calculation of the gross margin by taking into account the implicit and explicit cost parameters associated with the manifestation of leptospirosis. The prevalence rate of leptospirosis decreased from 49.4 % in 2015 to 21.6 % in 2017. There was a reduction in the abortion rate (from 40.00 % in 2014 to 9.00 % in 2017), in the stillborn rate (from 2.63 % in 2014 to 1.69 % in 2017) and an increase in the calving rate (from 65.00 % in 2014 to 86.00 % in 2017). In addition, there were increases in the number of lactating cows (from 38 in 2014–57 in 2017) and the mean times of lactation duration, which increased from 275 days in 2014–295 days in 2017. As a result, the average annual production of milk increased from 164,655 liters in 2014–248,521 liters in 2017. In 2014, when treatment hadn’t yet started, the gross margin per liter of milk sold, considering implicit and explicit costs, was US$0.00. In 2015 and 2016, US$0.27 and US$0.30 were obtained, respectively, for this variable. In 2017, with the disease under control on the property, the gross margin per liter of milk reached US$0.36. The gross margin per liter of milk sold was higher in the period when the disease was controlled, showing losses of up to 84 % of the gross margin during the outbreak. Immediate treatment of positive cows and preventive measures had a significant impact on improving the productive and economic efficiency of the property.

STATISTICAL STUDY OF SOME INDICATORS IN THE LIVESTOCK SECTOR

In this paper, some indicators covering milk production, weight gain and feeding efficiency are studied, such as the duration of lactation, total amount of milk, daily amount of milk, percentage of fat, protein, lactose in milk, for a representative sample taken from S.C.D.A Simnic. In the first part, a descriptive statistical analysis is made of the indicators in the zootechnical field presented, followed by econometric methods regarding confidence intervals for the average of the entire population, at a threshold of 5%. Also, the correlation matrix between the indicators is analyzed and three validated linear regression models are presented with the interpretation of the results. These results help to optimize management in the zootechnical field by making decisions based on quantitative analyses.

Dynamics of variation of dairy characteristics in cows when using the feed additive “VivAktiv”

Relevance. Holstein dairy cattle are bred in the Sverdlovsk region, its improvement is carried out by selecting and selecting the best for further breeding. In order for them to display their genetic potential of productivity, it is necessary to ensure a balanced diet. The aim of the work was to assess the diversity of dairy characteristics in Holstein cows when using the “VivAktiv” feed additive.Methods. To conduct the study, 4 groups of calved heifers with 10 heads each were formed in a typical breeding plant for the region: a control group and three experimental ones based on the principle of pairs of analogues. The dairy productivity of cows was evaluated for the first lactation and for the calendar year by control milking once a month. The fat and protein content in milk was assessed in an average milk sample once a month from each cow. The coefficient of variability (variation) was calculated according to the generally accepted formula.Results. As a result of the conducted research, it was found that the use of the “VivAktiv” feed additive did not significantly affect the productivity of cows. The milk yield for lactation by group was 10582.3 ± 187.35, 10640.8 ± 163.89, 10293.9 ± 176.45 and 10080.1 ± 178.13 kg, respectively, the difference was unreliable and insignificant. Considering the changes in the coefficient of variation between the groups, we can note a lower variability of the trait in cows of the 2nd experimental group. The animals of the control group came in second place. The largest variety of the trait turned out to be in the 3rd experimental group. Thus, the variability of the trait is influenced by the period (month) of lactation, to some extent the duration of lactation, as well as the use of the feed additive “VivAktiv”, which had a stabilizing effect on cow yield when used at a dose of 20 g/head/day.

Climate Perceptions of Small Ruminant Farmers in the Mouhoun Province of Burkina Faso

Perception is all about taking in, taking for oneself, taking hold of. Thus, a false perception of climate change can lead to a lack of adaptation or to maladaptation. Climate change represents a threat to the livestock farmers of the MP, whose main source of income is the exploitation of natural and animal resources. The problematic of this study is based on the good perception of the stockbreeders which were necessary to them to adapt to the climatic crises already occurred. The aim of this study is to analyze the perception of climate change by small ruminant breeders in the Mouhoun Province of Burkina Faso. To this end, 286 breeders, including agro-pastoralists and agro-pastoralists, i.e. 22 breeders per village, were surveyed. In addition, a focus group was held in each village, for a total of thirteen (13). Phinks software was used to process the individual survey data. The results indicate a drop in rainfall intensity (78.7%), a rise in temperatures (90.7%), a withdrawal from grazing areas (86%), a drop in milk production (81.3%) and lactation duration (86%). In summary, it appears that the population has a good perception of the climate in their locality. In addition, although it is difficult to integrate research evidence into development policy and practice, the results of this research could guide policy in making decisions about the climate perception of small ruminant farmers in the Mouhoun Province. This study leads to the conclusion that the changes perceived by farmers are relevant to the development of climate change adaptation strategies.

Prenatal exposure to low-dose bisphenol A disrupts hippocampal DNA methylation and demethylation in male rat offspring.

Earlier research has demonstrated that developmental exposure to bisphenol A (BPA) has persistent impacts on both adult brain growth and actions. It has been suggested that BPA might obstruct the methylation coding of the genes in the brain. In this study, the methylation changes in the hippocampus tissue of male rat pups were examined following prenatal BPA exposure. Pregnant Sprague-Dawley rats were treated with either vehicle (tocopherol-stripped corn oil) or BPA (4, 40, or 400μg/kg·body weight/day) throughout the entire duration of gestation and lactation. At 3weeks of age, the male rat offspring were euthanized, and the hippocampus were dissected out for analysis. The expression levels of DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B) and DNA demethylases (TET1, Gadd45a, Gadd45b, and Apobec1) were analyzed in the hippocampus by means of quantitative real-time polymerase chain reaction and Western blotting, respectively. The results showed that prenatal exposure to BPA upregulated the expression of enzymes associated with DNA methylation and demethylation processes in the hippocampus of male rat offspring. These findings suggest that prenatal exposure to a low dose of BPA could potentially disrupt the balance of methylation and demethylation in the hippocampus, thereby perturbing epigenetic modifications. This may represent a neurotoxicity mechanism of BPA.

Quantifying maternal investment in mammals using allometry.

Maternal investment influences the survival and reproduction of both mothers and their progeny and plays a crucial role in understanding individuals' life-history and population ecology. To reveal the complex mechanisms associated with reproduction and investment, it is necessary to examine variations in maternal investment across species. Comparisons across species call for a standardised method to quantify maternal investment, which remained to be developed. This paper addresses this limitation by introducing the maternal investment metric - MI -for mammalian species, established through the allometric scaling of the litter mass at weaning age by the adult mass and investment duration (i.e. gestation + lactation duration) of a species. Using a database encompassing hundreds of mammalian species, we show that the metric is not highly sensitive to the regression method used to fit the allometric relationship or to the proxy used for adult body mass. The comparison of the maternal investment metric between mammalian subclasses and orders reveals strong differences across taxa. For example, our metric confirms that Eutheria have a higher maternal investment than Metatheria. We discuss how further research could use the maternal investment metric as a valuable tool to understand variation in reproductive strategies.