Colour-Doppler ultrasonography (CDU) has been applied for a more detailed examination of the ovary and uterus, mainly local blood flow in ovarian follicles and the corpus luteum (CL). The main use of CDU is for the diagnosis of early pregnancy or the selection of recipients for embryo transfer in cattle; however, this tool can also be used to select oocyte donors according to blood flow to the ovary. The concept is that more blood flow in the ovary is conducive to a healthier intraovarian environment (e.g. higher progesterone levels and removal of reactive oxygen species), yielding higher quality oocytes. The objective of this research was to evaluate invitro embryo production (IVP) after selection of oocyte donors, considering ovary irrigation before ovum pickup (OPU). The research was carried out in the reproduction laboratory at the Palominos Ranch (Jalisco, México). The oocyte donors (n=15) were synchronized before each round of OPU using an intravaginal device (1.9g of progesterone) with oestradiol benzoate (2mg) and cloprostenol sodium (500µg) on Day 0, to avoid the presence of a corpus luteum and to synchronize the follicular wave. On Day 6, the intravaginal device was removed and OPU was performed. All Angus breed donors between 3 and 5 years old with a body condition score between 5–6 (scale 1–9, where 1 is extremely thin and 9 is very obese) and were evaluated with transrectal CDU (Sonoscape S2™) with a linear-array probe (7.5MHz) before the first OPU session only. The oocyte donors were classified subjectively into three categories: low blood flow (LBF, ∼30% ovarian area), median blood flow (MBF, ∼50% ovarian area), and high blood flow (HBF, ∼70% ovarian area) and were submitted to 3 cycles of IVP each (45 total cycles). Semen from a proven bull for IVF was used during all IVP cycles. All oocytes collected from each donor were used in IVF with the same semen in all IVP cycles. The total oocytes collected, and percentages of viable oocytes, cleavage, and blastocysts on Day 7 of culture were evaluated. Statistical analysis was carried out using the GLM procedure of SAS software (version 9.3; SAS Institute Inc.) to evaluate the results of LBF, MBF, and HBF (P-value=0.05). Total oocyte recovery was 11.28±1.92, 10.06±1.31, and 15.52±1.05 for HBF, MBF, and LBF, respectively, being significantly higher for LBF (P<0.05). There were no differences in viable oocytes among groups. Cleavage rates were 53.04%±3.43 for HBF, 43.18%±2.34 for MBF, and 43.69%±1.89 for LBF, being significantly higher for HBF (P<0.05). Percentage of blastocysts on Day 7 was 38.16%±3.80 for HBF, 30.11%±2.60 for MBF, and 17.78%±2.10 for LBF. This value tended to be significantly higher for HBF than MBF, and both were significantly superior to LBF (P<0.05). In conclusion, under the conditions of this research, although LBF donors had more total recovered oocytes, blastocyst rates were increased in HBF and MBF donors. Therefore, based on the results of the present study, CDU can be a useful tool for the selection of oocyte donors.
SexedULTRA-4M™ is made using an improved method of sex-sorting sperm in a less damaging environment for better retaining sperm integrity throughout the sorting process. The objective of this research was to compare conventional (CONV) and SexedULTRA-4M™ (ULTRA-4M) semen for bovine IVP using four Angus bulls. Matured slaughterhouse oocytes (n = 4000) were divided into the CONV group and the ULTRA-4M group (2000 COCs for each semen type). The IVF process was implemented with CONV and ULTRA-4M semen from the same bull. The cleavage rates, eight cell embryos and blastocysts on day 7 of culture were evaluated for each semen type and each bull. The statistical analysis was carried out with the ANOVA procedure SAS software. The results were 54.45% ± 1.03 and 58.10% ± 1.07; 35% ± 1.57 and 39.15% ± 1.62; 22.8% ± 1.09 and 27.15% ± 1.12 for CONV and ULTRA-4M, respectively, for cleavage rate, eight cell embryos and blastocysts on day 7 for the average of all bulls, comparing only the semen type. Concerning only the semen type, ULTRA-4M was significantly superior to CONV for cleavage rates (P = 0.01) and blastocysts on day 7 (P = 0.009). There were no significant differences between the CONV and ULTRA-4M groups (P>0.05) for all variables analyzed for Bull 1 and Bull 4, however, for Bull 2 ULTRA-4M was significantly superior to CONV for cleavage rates and blastocysts on day 7 (P< 0.05). In Bull 3, ULTRA-4M was significantly higher (P< 0.05) for blastocysts on day 7 compared to CONV. In conclusion, under the conditions of this research the ULTRA-4M and CONV semen produced similar bovine IVP results overall.
El objetivo fue evaluar el impacto de factores asociados al manejo de la madre y la calidad del calostro sobre la crianza de reemplazos bovinos durante la lactancia, en el sistema de producción de leche a pequeña escala. En 13 unidades de producción se obtuvo información del crecimiento corporal, la alimentación con calostro e información asociada a la madre de 220 becerras Holstein. Las variables de interés fueron: morbilidad, concentración de inmunoglobulinas en el calostro (CIC; <110 mg/ml), concentración de proteína sérica (CPS; <6.6 g/dl), ganancia diaria de peso (GDP; <0.650 kg/día) y ganancia diaria de altura (GDA; <0.222 cm/día). Los factores de estudio fueron: peso corporal al nacimiento (PCN; <42 kg), altura al nacimiento (AN; <82 cm), calostro consumido el primer día (CCPD; <4 l), calostro consumido el primer día/kg de PV (CPDPV), condición corporal al parto (CCP; <3), duración del periodo seco (DPS; >68 días), vacas primíparas (VP) y vacas sin dieta de reto (VSDR). Para determinar el impacto de los factores de estudio sobre los eventos de interés, se obtuvo la razón de momios a partir de análisis de regresión logística múltiple. Los factores identificados para morbilidad fueron CCPD y VP (P<0.1). Los factores para CIC fueron la DPS y VSDR (P<0.1), mientras que para la GDP lo fue VSDR (P<0.1). Finalmente, los factores para GDA fueron VSDR, PCN, AN y CPDPV (P<0.1). Estos resultados sugieren que la nutrición de la madre durante la gestación tardía tiene un impacto importante sobre la salud y el desarrollo corporal de las becerras durante la lactancia. Estudios adicionales deberán determinar los efectos a largo plazo.
In tropical, subtropical and arid zones, heat stress is the main cause of productivity reduction in cattle. When climate stressors occur, animals are thermal adapted through differential expression of some genes, including HSP family. The aim of this study was to determine levels of expression of HSP60, HSP70 and HSP90 genes in Simmental cattle raised in tropical environments of Mexico. MethodsIn this study, expression of HSP60, HSP70 and HSP90 genes was analyzed in 116 Simmental cattle from three farms with tropical climate located in western Mexico. Animals were sampled twice a day, in the morning and noon. Gene expression was evaluated by qPCR using probes marked with fluorescence. The MIXED procedure of SAS with repeated measures was used for all statistical analysis. ResultsHSP60 gene expression differences were found for sex (p=0.0349). HSP70 gene differences were detected for sampling hour (p=0.0042), farm (p<0.0001), sex (p=0.0476) and the interaction sampling hour x farm (p=0.0002). Gene expression differences for HSP90 were observed for farm (p<0.0001) and year (p=0.0521). HSP70 gene showed to be a better marker of heat stress than HSP60 and HSP90 genes. ConclusionExpression of HSP70 gene in Simmental herds of the tropical region of western Mé xico was different during early morning and noon, but the expression of the HSP60 and HSP90 genes was similar. Identification of resilient animals to heat stress will be useful in the genetic improvement of the Simmental breed.
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