The aim of this study was to evaluate the effects of dose and application time of pregnant mare serum gonadotropin (PMSG) on reproductive performance of hair sheep ewes synchronized with fluorogesterone acetate (FGA) under tropical conditions of Northeastern Mexico. Ninety-nine hair ewes (63 Blackbelly and 36 Pelibuey) were treated with intravaginal sponges during 10 days. After insertion of FGA sponges, ewes were divided into four groups, and PMSG was injected intramuscularly at doses of 100, 200, and 400 IU. Relative to FGA sponge removal, PMSG was administrated at -48 h, -24 h, and at sponge removal. PMSG was not administered to the control group. Control ewes had similar (P > 0.05) lambing rate, fertility, and fecundity than those treated with 100 IU of PMSG, but lower (P < 0.05) percentages to these variables than those treated with 200 and 400 IU of PMSG. Time to estrus decreased linearly, and ovulation rate increased quadratically as PMSG dose increased (0 to 400 IU). Administration of PMSG before sponge removal increased (P < 0.01) response to estrus and decreased (P < 0.01) interval to estrus compared with control. Ovulation rate, lambing rate, fertility, and fecundity were not affected (P > 0.05) by administration time of PMSG. Both dose and time of PMSG application did not affect (P > 0.05) pregnancy rate, percentage of single and multiple lambing, and prolificacy. In conclusion, results show that the dose of 400 IU of PMSG administered before sponge withdrawal in an estrus synchronization protocol improved reproductive efficiency of hair sheep ewes.

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Twenty Dorper x Pelibuey male lambs were used to evaluate the effect of substitution of forage with fresh orange pulp (FOP) in diets for fattening lambs on productive behavior, nutrient intake, apparent digestibility coefficient, and feeding costs. Lambs were divided into five groups (n = 4) and then housed in individual pens during 70 d. Treatments consisted of five levels of FOP (0, 25, 50, 75 and 100%) which substituted buffel grass hay on the base diet (40:60%, forage:concentrate). Additionally, changes in chemical composition of FOP stored in stack during 8 d were evaluated (from the day 1 until day 8). Daily feed intake expressed as kg/day and % live weight, lamb growth rate, feeding cost of each lamb per day and per fattening period, hemicellulose intake, and DM, OM, CP, NDF and hemicellulose digestibility showed a quadratic effect (P < 0.05), while DM, OM and CP intake presented a cubic effect (P < 0.05) with the increasing level of FOP. The maximum estimated value for those variables was observed at 75% of hay replacement with FOP. With respect to changes in chemical composition of pulp stored, DM content increased (P = 0.0011) from 210 to 310 g/kg FOP and OM, fiber fraction, and ash content were constant (P > 0.05) among storage days. Therefore, replacing around 75% of buffel grass hay with FOP in diets for fattening lambs resulted in the best growth rate and more efficient diet utilization. Fresh orange pulp stored in a stack did not change its chemical composition, and did not affect its utilization as a sheep feedstuff.

The period of both in vitro maturation (IVM) and incubation with oocyte activators affects the blastocyst yield following parthenogenetic activation (PA). Nevertheless, it is still unknown how these conditions impact the expansion and hatching rates of bovine parthenogenetic blastocysts. The objective of this study was to assess the influence of the duration of IVM and exposure to the activating agent, 6-dimethylaminopurine (6-DMAP), on a number of developmental parameters in bovine parthenotes, including: Cleavage, blastocyst formation, expansion, and hatching. Slaughterhouse oocytes were subjected to different periods of IVM. Subsequently, eggs were first parthenogenetically activated for five minutes with ionomycin and then incubated for distinct lengths of time with a second activator, 6-DMAP. The treatments were: a) Control: 22 h IVM/4 h 6-DMAP; b) 22 h IVM/5 h 6-DMAP; c) 24 h IVM/4 h 6-DMAP; and d) 24 h IVM/5 h 6-DMAP. Developmental stages were evaluated at day 4 and day 8 of in vitro culture (IVC). No differences were detected in most developmental parameters. However, the duration of IVM and incubation with 6-DMAP significantly affected (P<0.05) hatching capacity considering the number of blastocysts (Hatch./Blast.). Also, this same variable was higher (P<0.05) in group b) 22 h IVM/5 h 6-DMAP (45.89 ± 12.59%), as compared to c) 24 h IVM/4 h 6-DMAP (6.67 ± 6.67%). In conclusion, the length of IVM and incubation with 6-DMAP influenced parthenogenetic development, where 22 h IVM/5 h 6-DMAP was the condition producing the highest Hatch./Blast. rate in bovine parthenotes.

La retención placentaria (RP) es uno de los trastornos reproductivos más comunes que afecta a las vacas lecheras; sin embargo, los factores de riesgo no están completamente establecidos. El objetivo fue determinar la relación entre diferentes factores de riesgo para PR en el norte de México. Se utilizaron los registros productivos de 2,483 vacas Holstein en Ciudad Juárez, Chihuahua, México. Las variables se analizaron mediante una prueba X2. Se calcularon las razones de momios (odds ratio; OR) y se realizó un análisis de correlación canónica para determinar la influencia de los factores de riesgo con RP y la influencia de RP sobre los parámetros reproductivos. La incidencia total de RP fue del 10.15%. Los factores de riesgo con mayor OR fueron nacimiento gemelar y nacimiento prematuro, seguidos por mortinatos y distocia. Ninguna temporada de parto incrementó la presencia de PR. La presencia de PR no aumentó la presencia de metritis. El análisis de correlación canónica fue significativo para parto gemelar, mortinatos, nacimiento prematuro y distocia, pero no para la temporada de parto. Existe una correlación significativa de PR con la cantidad de servicios para lograr gestación, el número de lactancias y los días en leche. En conclusión, los factores de riesgo parto gemelar, parto prematuro, mortinatos, distocia y edad de la vaca afectan la incidencia de RP, mientras que la temporada de parto no predispone a la presentación de esta alteración. PR no aumenta la presencia de metritis o la cantidad de servicios, pero reduce los días en leche.

Objective: To test whether HTF (Human Tubal Fluid) is capable of protecting goat sperm cells increasing the semen m Objective: To determine if HTF (Human Tubal Fluid) can protect buck sperm cells, increasing semen motility when used by itself or combined with the Andromed® commercial extender. Design/Methodology/Approach: The semen of eight bucks of the Boer breed was used (10 ejaculates per male). Each ejaculate was diluted in three treatments (5 repetitions per treatment): 1) only Andromed®; 2) only HTF; and 3) Andromed® + HTF. The following variables were evaluated: mass motility (MM) and progressive motility (MP) in fresh (37 °C) and refrigerated (5 °C) semen. The differences between treatments were detected, based on the MM and MP in fresh and refrigerated semen variables, using the GLM procedure (SAS V9). In the case of the MM evaluated in three different periods, the measures repeated over time were analyzed using the Proc Mixed procedure (SAS V9). Results: Regarding the quality of fresh spermatozoa, MM and MP recorded similar values (p>0.05) for the three treatments. On the one hand, MM registered 97.1% for Andromed®, 95.8% for HTF, and 97.5% for Andromed® + HTF; its highest value was achieved with the Andromed® + HTF combination, followed by Andromed® and HTF. On the other hand, the highest MP percentage was observed with the combination of Andromed® + HTF (91.0%), followed by Andromed® (90.4%), and HTF (89.0%). Regarding the quality of the sperm refrigerated at 5 °C, the combination of Andromed® + HTF had a higher MP value (p<0.05) than other treatments. Study Limitations/Implications: In all the evaluated treatments, the motility of sperm decreased over time (0 to 24 hours after cooling); however, the treatments with Andromed®, and Andromed®+HTF maintained a high motility. Findings/Conclusions: The combination of Andromed® and HTF can be used to dilute both fresh and cooled semen.

Objective: to evaluate the effect of breed, reproductive season, dose and time of application of equine chorionic gonadotropin (eCG) on the estrous cycle and ovarian activity in hair ewe lambs. Design/methodology/approach: 216 Hair lambs were used (62 Dorper, 69 Katahdin y 85 Pelibuey), 91 in the high reproductive season and 125 in the low reproductive season, they were synchronized with intravaginal sponges containing 20 mg of fluorogestone acetate (FGA) and equine chorionic gonadotropin (eCG; 200 and 300 IU) intramuscularly. The treatments are the breed, reproductive season, dose and time of application of eCG. The presence of estrus was analyzed under a logistic regression model, the interval to estrus and ovulation rate were analyzed by analysis of variance using a completely randomized design with a 2x2x2x3 factorial arrangement with the PROC LOGISTIC and PROC GLM procedures. Results: the breed influenced (P<0.01) the presence of estrus, Dorper ewe lambs presented 9.74 times more possibilities than the Pelibuey. The interval to estrus was shorter in duration (P<0.05) in Dorper (29.5±0.9 h) and Katahdin (29.1±0.9 h) compared to Pelibuey (34.8±0.9 h). The interval to estrus was lower (P<0.05) with the application of 200 or 300 IU of eCG 24 h before the end of the protocol, compared to the application of 200 IU of eCG at the time of progestogen withdrawal. Ovulation rate was only affected by breed (P<0.05), being higher in Pelibuey (2.4±0.1) compared to Dorper (2.0±0.1) and Katahdin (1.9±0.1). Study limitations/implications: To complement the study, it would be convenient to take the research to a second phase where the gestation part of the females is included to relate it to the ovulation rate, and also to make measurements of ovarian structures by means ultrasound. Findings/conclusions: Estrus and ovarian activity in hair ewe lambs synchronized with progestogens is mainly influenced by breed.