Early postpartum administration of equine chorionic gonadotropin to dairy cows calved during the hot season: Effects on fertility after first artificial insemination

Heat stress reduces fertility of high-producing dairy cows, and early administration of equine chorionic gonadotropin (eCG) may improve it. Here, 401 heat-stressed, high-producing dairy cows on a single commercial farm were given eCG (500 UI, n = 214) or saline (n = 187) on days 11–17 after calving, and the effects on fertility after the first artificial insemination (AI) were assessed. On post-partum day 96.34 ± 9.88, all cows were inseminated after a “double short Cosynch” synchronization protocol. Ovarian activity and uterine status were checked by ultrasound on the day of eCG administration and every 7 days thereafter for a total of 3 weeks; checks were also performed during synchronization, and 7 days after AI. On post-partum day 30, cytobrush uterine cytology was performed to check for subclinical endometritis. Pregnancy status was checked on days 30 and 60 after AI. The eCG and control groups did not differ significantly in terms of average lactations per cow (2.33 ± 1.34), days in milk at first AI (96.33 ± 9.88), average milk yield at AI (41.38 ± 7.74 L), or the particular inseminator or bull used for AI. The eCG and control groups showed increasing ovarian activity with time, with approximately 75% of cows in both groups showing a corpus luteum at the beginning of the synchronization protocol. On post-partum day 30, 17.4% of eCG cows and 22.9% of control cows showed subclinical endometritis. Cows treated with eCG showed a tendency toward lower hyperecogenic intraluminal content (16.8 vs. 21.4%, P = 0.15), but ovarian activity during the synchronization protocol was similar between eCG and control groups, with 91% of animals in both groups showing luteolysis after prostaglandin application and 88% showing ovulation after the last administration of gonadotropin-releasing hormone. Fertility was similar between the two groups at both time points after AI (30 days, 34.9 vs. 31.8%; 60 days, 30.6 vs. 28.5%; P > 0.2). These results suggest that early postpartum eCG administration does not improve fertility of heat-stressed dairy cows as long as 60 days after AI. Other strategies may be more effective at mitigating the ability of post-partum heat stress to reduce fertility of high-producing dairy cows

Beef Nutritional Characteristics, Fat Profile and Blood Metabolic Markers from Purebred Wagyu, Crossbred Wagyu and Crossbred European Steers Raised on a Fattening Farm in Spain

A high intramuscular fat content characterizes Wagyu (WY) cattle breed. Our objective was to compare beef from WY, WY-by-Angus, or Wangus (WN) steers with European, Angus-by-Charolais-Limousine crossbred steers (ACL), considering metabolic biomarkers pre-slaughtering and nutritional characteristics, including health-related indexes of the lipid fraction. The fattening system with olein-rich diets and no exercise restriction included 82 steers, 24 WY, 29 WN, and 29 ACL. The slaughter ages and weights were (median and interquartile range) 38.4 mo.-old (34.9–40.3 mo.) and 840 kg (785–895 kg) for WY; for WN, 30.6 mo. (26.9–36.5 mo.) and 832 kg (802–875 kg), and for ACL steers, 20.3 mo.-old (19.0–22.7 mo.) and 780 kg (715–852 kg). Blood lipid-related metabolites, except for non-esterified fatty acids (NEFA) and low-density level cholesterol (LDL), were higher in WY and WN than in ACL, while glucose was lower in WY and WN. Leptin was higher in WN than in ACL. Pre-slaughtering values of plasma HDL underscored as a possible metabolic biomarker directly related to beef quality. The amino-acid content in beef did not differ among experimental groups, except for more crude protein in ACL. Compared to ACL, WY steers showed higher intramuscular fat in sirloin (51.5 vs. 21.9%) and entrecote (59.6 vs. 27.6%), more unsaturated fatty acids in entrecote (55.8 vs. 53.0%), and more oleic acid in sirloin (46 vs. 41.3%) and entrecote (47.5 vs. 43.3%). Compared to ACL entrecote, WY and WN showed better atherogenic (0.6 and 0.55 vs. 0.69), thrombogenicity (0.82 and 0.92 vs. 1.1), and hypocholesterolemic/hypercholesterolemic index (1.9 and 2.1 vs. 1.7). Therefore, beef’s nutritional characteristics depend on breed/crossbred, slaughtering age and cut, with WY and WN entrecote samples showing a healthier lipid fractio

Resincronización con un protocolo de G6G: un estudio retrospectivo de segundas y ultimas inseminaciones artificiales

We recorded conception rates and estimated pregnancy rates following second and later timed artificial inseminations (TAI) after hormonal resynchronization on commercial dairy farms, using the so-called G6G protocol (PGF day-0; GnRH 2, 8d; PGF 15, 16d, GnRH 17d; TAI 18d), and the 5 day Ovsynch protocol or 5DO (GnRH day 0; PGF 5, 6d; GnRH 7d; TAI 8d). In four farms both protocols were implemented in parallel, and these 1,368 second and later TAIs were used for the protocols' comparison based on logistic regression [544 TAIs in primiparous; 824 in multiparous cows; 1024 TAIs after G6G (600 TAIs in multiparous, 424 in primiparous); 344 TAIs after 5DO (224 TAIs in multiparous, 120 in primiparous); 280 TAIs during the hot season; 1088 during the cool season]. Conception rate (CR) was 31.7 ± 12.0% among all cows, 35.1 ± 10.7% among cows resynchronized with the G6G protocol and 21.8 ± 9.7% among cows resynchronized with the 5DO protocol (P0.1) no interaction with season or resynchronization protocol was found. Estimated pregnancy rates based on these CR data from both hormonal protocols, suggest that G6G can be effectively used for second and later TAIs and highlight the importance of considering protocol and season when designing strategies for second and later timed AIs on dairy farms. This article is protected by copyright. All rights reserved

Programación prenatal y epigenética en pequeños rumiantes

Los cambios epigenéticos son modificaciones hereditarias reversibles de la expresión génica que se producen al alterar la secuencia de ADN en estadios de desarrollo temprano. Su objetivo es la adaptación a las condiciones medioambientales en que se va a desarrollar el individuo. Las condiciones prenatales (intrauterinas) influyen marcadamente en el crecimiento juvenil y en el fenotipo adulto.Los cambios epigenéticos son modificaciones hereditarias reversibles de la expresión génica que se producen al alterar la secuencia de ADN en estadios de desarrollo temprano. Su objetivo es la adaptación a las condiciones medioambientales en que se va a desarrollar el individuo. Las condiciones prenatales (intrauterinas) influyen marcadamente en el crecimiento juvenil y en el fenotipo adulto

Impact of body condition on fertility in cows of the province of Pastaza-Ecuador

El objetivo fue evaluar el efecto de la condición corporal sobre la fertilidad en vacas de la provincia de Pastaza-Ecuador. Se utilizaron 2434 registros reproductivos de la base de datos entre el 2009- 2013. Las variables analizadas fueron: estado reproductivo gestante y no gestante, año, raza, condición corporal (CC), celo, toro o pajuela utilizada, técnico inseminador. La muestra para el análisis estadístico de los datos se basó en tres modelos de ANOVA y un modelo mixto. El porcentaje de preñez a nivel provincial logrado con este programa de mejoramiento fue del 60 al 69%. La CC solo fue significativa para la raza Charolais mestiza, quien mostró un coeficiente de correlación lineal bajo negativo con respecto a la gestación, las otras variables celo, pajuela, técnico tampoco tuvieron diferencias estadísticas (P>0.05). Pero en el análisis del segundo modelo aplicado se encontró diferencias significativas entre el lugar (cantón) y CC (P=0.047) y entre la raza de la vaca y raza del toro (P=0.006). Se concluye que la (CC) influyó sobre la gestación dependiendo del lugar, independiente de la raza de la vaca, factor que no resultó importante en la variable reproductiva estudiada, los factores ambientales: año, cantón y CC, influyen en los niveles de gestación de la población estudiada, de los factores genéticos analizados las razas de la vaca y del padre no influyeron, solamente el factor toro fue importante en la gestación de la vaca y el factor humano resultó determinante como causa de variación en la gestación.The objective was to evaluate the effect of body condition on fertility in cows from the province of Pastaza-Ecuador. We used 2434 reproductive records from the database between 2009-2013. The variables analyzed were: pregnant and non-pregnant reproductive status, year, race, body condition (CC), heat, bull or straw used, technical inseminator. The sample for the statistical analysis of the data was based on three models of ANOVA and a mixed model. The percentage of pregnancy at the provincial level achieved with this improvement program was 60 to 69%. The CC was only significant for the Charolais mestizo breed, which showed a negative linear correlation coefficient with respect to gestation, the other estrus, straw, and technical variables also did not have statistical differences (P> 0.05). But in the analysis of the second applied model, significant differences were found between the place (canton) and CC (P = 0.047) and between the breed of the cow and bull breed (P = 0.006). It is concluded that the (CC) influenced the gestation depending on the place, independent of the race of the cow, a factor that was not important in the reproductive variable studied, the environmental factors: year, canton and CC, influence the levels of pregnancy of the studied population, of the genetic factors analyzed, the breeds of the cow and the father did not influence, only the bull factor was important in the gestation of the cow and the human factor was determinant as a cause of variation in the gestation

Factors affecting pregnancy loss in dairy cows

Objectives: The objectives of this study were to examine possible relationships between pregnancy loss (described as the loss of pregnancy occurred after a positively diagnosed pregnancy -days 28-40- and before day 110 of pregnancy) and different factors such as synchronization protocol used, parity, number of Artificial Insemination (AI), days in milk at AI, age at AI (in the case of heifers) and the fact of having had a previous pregnancy, in dairy cows managed under intensive milk production systems. Material and methods: A total of 12978 AIs from seven different farms were included in the study. The number of AIs from each farm were 812/12978 from farm 1 (6.3%), 710/12978 from farm 2 (5.5%), 1865/12978 from farm 3 (14.4%), 4104/12978 from farm 4 (31.6%), 1530/12978 from farm 5 (11.8%), 589/12978 from farm 6 (4.5%) and 3368/12978 from farm 7 (26.0%). A total of 5119 were first AIs and 7859 were second or more AIs (from them 1729 were 5th or more AIs). The AIs were performed in animals with different lactation orders, with 1586 AIs having been in heifers (only from farms 4 and 7), 3983 in primiparous cows, and the rest in multiparous cows (with lactation order up to 9th). Synchronization protocols recorded were observed estrus, G6G, Double Ovsynch, Presynch, Ovsynch (with or without intravaginal dispositive), 5dCosynch (with or without intravaginal dispositive). A total of 10186 AIs was performed during the cool season (September to May) and 2792 during the hot season (June, July and August). Straightforward stepwise Wald logistic regression analysis was used to study the influence of the different factors, including the factor farm as covariable in the model. Results: Average conception rate for all AIs was 36.7%, and average pregnancy loss was 13.9% (664/4764). The range among farms oscillated from 9.5% (28/294) to 16% (194/1209), with the factor “farm” being a significant one affecting pregnancy loss (P<0.0001). When all AIs were included into the model (controlled including the factor “farm” in the model), significant factors affecting pregnancy loss were season with the hot season increasing the risk of pregnancy loss (11.6 vs. 14.5%; OR, 1.539; 95% CI, 1.215–1.949; P<0.0001); the number of AIs, with second or more inseminations showing an increased risk (14.2 vs. 10.5% for first and second or more AIs, respectively; OR, 0.696, 95% CI, 0.581–0.834; P<0.0001), the parity using the stage of heifer (nulliparous) as reference value, and both primiparous and multiparous increasing the loss risk when compared to the heifers (7.8 vs. 9.9 vs. 14.7% for heifers, primiparous and multiparous, respectively; OR, 1.854, 95% CI, 1.330–2.585; P<0.0001 for primiparous cows, and OR, 3.057, 95% CI, 2.248–4.157; P<0.0001 for multiparous cows). The fact of having had a pervious pregnancy loss was demonstrated as a “protective factor (OR, 0.445, 95% CI 0.278–0.713; P<0.0001). Synchronization protocol did not affect significantly pregnancy loss. When heifers were separately studied (n=1586 AIs), in order to explore the effect of age at insemination a significant effect of this factor was (OR, 1.026, 95% CI, 1.016– 1.035; P<0.0001), besides the significant effect of number of AI observed with second or more inseminations showing less rates of pregnancy loss (OR, 0.305, 95% CI, 0.120–0.774; P=0.012). In the case of primiparous cows separately analyzed (n=3982 AIs), besides farm (P<0.0001) and season (OR, 1.855, 95% CI, 1.252–2.747; P=0.002) no other factor was kept in the model as significant factor; and in the case of multiparous cows (n=7409AIs) season (OR, 1.647, 95% CI, 1.221–2.221; P=0.001), second or more insemination (OR, 0.640, 95% CI 0.513–0.799; P<0.0001) and having had a pervious pregnancy loss (OR, 0.340, 95% CI 0.189–0.610; P<0.0001) influenced significantly pregnancy loss. Synchronization protocol and days in milk at insemination did not significantly affect the risk of having pregnancy loss in adult cows (P>0.05). Conclusions: Our study suggests that the cool season, a higher number of insemination, a younger age of the dam in the case of heifers and having previously suffered pregnancy loss are protective factors for pregnancy loss. However, these factors seem to affect in a different way depending if the inseminations are performed on heifers, primiparous or multiparous cows, which highlights the different reproductive characteristics of the dairy cattle.Sappor

Estándares de sustentabilidad para viviendas patrimoniales del Centro Histórico de Cuenca-Ecuador

The aim of the study is to analyze the standards of energy efficiency and quality of the indoor environment of the heritage dwellings in the Historic Centre of Cuenca, considering the following factors: energy consumption, temperature, indoor air quality, natural lighting and acoustic comfort. The methodology used is mixed and of longitudinal design, involving quantitative and qualitative variables for the evaluation of environmental and electrical measurements, as well as the perceptions of comfort of the occupants of the houses. In a first stage, a survey is carried out to 280 houses in Cuenca to determine energy consumption habits and indoor environment conditions; in a second phase, a monitoring of electrical and environmental variables is carried out in three houses with patrimonial characteristics, through the use of measurement sensors, simulations and perception surveys. Subsequently, the results are analyzed and evaluated in order to compare them with energy efficiency and indoor environment quality standards of national and international standards, determining results that demonstrate that users adapt to comfort conditions different from those established by standards, such as temperature, where users, in response to the Andean climate, admit lower ranges than the established standards.El estudio tiene por objetivo analizar los estándares de eficiencia energética y calidad del ambiente interior de las viviendas patrimoniales del Centro Histórico de Cuenca, considerando los siguientes factores consumo de energía, temperatura, calidad del aire interior, iluminación natural y confort acústico. La metodología empleada es mixta y de diseño longitudinal, involucrando variables cuantitativas y cualitativas para la evaluación de las mediciones ambientales, eléctricas, así como las percepciones de confort de los ocupantes de las viviendas. En una primera etapa se realiza una encuesta a 280 viviendas de Cuenca para determinar hábitos de consumo energético y condiciones del ambiente interior; en una segunda fase se ejecuta un monitoreo de las variables eléctricas y ambientales en tres viviendas de características patrimoniales, mediante el uso de sensores de medición, simulaciones y encuestas de percepción. Posteriormente se analizan y evalúan los resultados para compararlos con estándares de eficiencia energética y calidad del ambiente interior de normas nacionales e internacionales, determinando resultados que demuestran que los usuarios se adaptan a condiciones de confort diferentes a los establecidos por normas, tal es el caso de la temperatura, donde los usuarios, como respuesta al clima andino, admiten rangos inferiores a los estándares establecidos

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Effects of maternal factors on the metabolic profile throughout pregnancy in dairy sheep

Objectives: Physiological states as pregnancy and lactation modify metabolism in sheep. The aim of this study was to evaluate the influence of pregnancy features (parity and type of pregnancy) on the maternal metabolism in high yielding Lacaune dairy sheep. Material and methods: The study was carried out in a single commercial farm on 334 Lacaune dairy sheep, classified by age (187 mature and 147 maiden ewes), parity (145 multiparous vs. 42 primiparous) and type of pregnancy (161 single vs. 173 multiple). Fasting plasma samples were collected at two points during pregnancy mid and late-pregnancy (74±5 and 141±3 d, respectively) and postpartum (52±5 d after delivery). The following metabolic parameters were considered: plasma ß-hydroxybutyrate (ß-OHB), nonesterified fatty acids (NEFA), glucose, lactate, urea, cholesterol, triglycerides and fructosamine. Differences among groups and interactions were evaluated with ANOVA and Kruskal-Wallis test when non-normal distributed. Results: ß-OHB was higher during gestation in mature than in maiden ewes (0.58±0.20 vs. 0.37±0.11 mmol/L; P< 0.0001) at mid pregnancy, (0.67±0.34 vs. 0.55±0.21 mmol/L; P< 0.0001) and late pregnancy, but did not differ with age at postpartum (0.78±0.25 vs. 0.74±0.23 mmol/L; P> 0.05). During gestation ß-OHB was not affected by type of pregnancy, although, postpartum ß-OHB was lower in ewes that had carried out single gestation than in those with multiple pregnancy (0.59±0.27 vs. 0.65±0.31 mmol/L; P< 0.01). At mid pregnancy NEFA were lower in mature than in maiden ewes (0.46±0.22 vs. 0.57±0.17 mmol/L; P< 0.0001); whereas NEFA were higher in mature at late pregnancy and postpartum (0.67±0.29 vs. 0.55± 0.18 mmol/L; P< 0.0001 for late pregnancy); (0.50±0.18 vs. 0.44±0.16 mmol/L; P=0.004 for postpartum). At late pregnancy, ewes carrying a single pregnancy showed lower NEFA than those with multiple foetuses (0.57±0.25 vs. 0.67±0.25 mmol/L; P< 0.0001). Glucose levels during gestation did not differ with age, however, at postpartum mature ewes had lower levels than maiden ewes (67.90±6.44 vs. 74.63±7.54 mg/dl P<0.0001). Glucose during gestation was higher in ewes carrying a single gestation at mid (65.45±15.48 vs. 60.44±8.82 mg/ dl; P< 0.004) and late pregnancy (71.84±14.62 vs. 67.37±12.53 mg/dl; P<0.003) but did not differ postpartum. Lactate was lower in mature ewes at mid pregnancy (16.34±8.73 vs. 18.85±10.13 mg/dl; P<0.003), and postpartum (11.13±6.90 vs. 12.07±5.64 mg/dl; P<0.01), but it was similar at late pregnancy and did not change by type of pregnancy. Urea was higher in mature ewes at mid pregnancy (57.44±11.23 vs. 39.95±7.86 mg/dl; P<0.0001) and postpartum (67.56±15.01 vs. 58.18±13.53 mg/dl; P<0.0001), but lower at late pregnancy (41.44±10.70 vs. 42.31±8.81; P<0.048). Urea was higher at late pregnancy in ewes carrying a single gestation (43.29±10.15 vs. 40.45±9.50 mg/dl; P<0.004). Cholesterol was higher during gestation in mature than in maiden ewes (P<0.0001). However, at postpartum cholesterol was higher in maiden ewes (108.79±21.76 vs. 100.44±21.74 mg/dl; P<0.001) and it was not affected by type of pregnancy. Triglycerides were higher in mature ewes (23.51±8.04 vs. 19.29±7.33 mg/dl; P< 0.001) at mid pregnancy. At postpartum, triglycerides were higher in maiden ewes (17.73±8.62 vs. 15.07±4.37mg/dl; P<0.001) and did not differ with type of pregnancy. Fructosamine was higher at mid gestation in mature ewes (310.77±31.63 vs. 275.47±30.58 umol/L; P<0.0001) and at the same time, it was affected by type of pregnancy (289.75±36.95 vs. 300.30±33.90 umol/L for single and multiple pregnancies respectively; P=0.013). The daily average milk yield during the lactation was not different between primiparous and multiparous (312.42±130.68 vs. 339.6±0.142.9 L; P>0.05); before getting pregnant, primiparous produced less than multiparous (1.71±0.62 vs. 2.07±0.67 L; P<0.05), and after conception primiparous produced the same as multiparous (1.11±0.38 vs. 1.07±0.46 L; P>0.05). Milk yield was not affected by type of pregnancy. Conclusions: The present data reveal interactions among maternal factors (age and type of pregnancy) physiological status (pregnancy and lactation) and time of pregnancy on the metabolism of dairy ewes, which be related to health and productivity.Sappor

Las explotaciones lecheras no tienen que asumir una mala eficiencia reproductiva

Sin lugar a dudas, la eficiencia reproductiva compromete la rentabilidad de los rebaños. Desde los años 60, hemos ido observando como los indices reproductivos, en especial la tasa de concepción, ha ido disminuyendo a medida que la producción por lactacion y vaca se eleva