The objective of this study was to investigate the immunocastration using against gonadotropin-releasing factor (GnRF) with Bopriva® (Zoetis) on the performance of production variables, meat quality, docility, and scrotal circumference in young rams, from Sheep production center “Tupac Amaru”, Junin region, Perú. A total of 60 animals were divided into four treatments: T1, T2, and T3 with 0.50 mL, 0.75 mL, and 1.0 mL of doses with Bopriva®, respectively, and T4 (control - 1.0 mL of placebo (distilled water)), with fifteen animals in each. The variables were measured every 15 days for three months (September to November 2018). Datasets were assessed by one-way ANOVA and subsequent posthoc Tukey´s test to detect significant differences among treatments. The results indicated differences found between treatments with the immunocastration compared with non-castrated animals for final weight, carcass weight and performance, scrotal circumference, and docility. Growth performance and meat quality characteristics were not adversely affected by immunocastration. Likewise, immunocastration with Bopriva proved to be effective to stop scrotal development and consequently reduces the sexual and aggressive behavior of young rams. The dose of 0.5 mL seems to be adequate due showed better performance for most variables compared to other treatments

The objective of this research was to evaluate the effect of sperm on chromatin stability and its relationship with the membrane integrity structural – physiological and the rate of fertilization of female sheep. Ejaculates of sperm (2 × 109 sperm·mL-1) with 70% of motility were collected using an artificial vagina (n=5, 2 years old. For this, each ram was served with fifteen female sheep (n=75), generating thus five different Groups (A, B, C, D, and E). A control Group also was considered. Sperm nuclear chromatin stability (NCS) was evaluated using the Borate Buffer (BB), Sodium Dodecyl Sulfate (SDS), and the mixture of Ethylenediaminetetraacetic acid (EDTA) + SDS. The fertilization rate was evaluated after 16-18 hours post sperm injection. Sperm concentration showed a significant difference (P<0.05) between Groups. In Contrast, seminal volume, and sperm motility do not show a significant difference (P>0.05). A high correlation (r2=0.52) was observed between morphology and motility, and the fertilization rate was 74.6% (n=56). It was concluded in general that techniques to evaluate nuclear condensation values do have a high likelihood to give a diagnosis about the future potential of sperm populations in Junín ram.

This study aimed to determine protein and energy metabolites in postpartum Brown Swiss cows and their effect on the presence of subclinical ketosis and reproductive parameters. One hundred cows from four farms in the Mantaro Valley (Junín, Perú) were grouped according to parity (1, 2, 3 and 4). The variables of the metabolic profile (total proteins, blood urea nitrogen [BUN], glucose, βhydroxybutyrate [B-HB]), milk production and body condition were estimated between 7 to 60 days postpartum in 7-day intervals. Likewise, the calving-first heat interval and the pregnancy rate at first service were recorded. The determination of subclinical ketosis was based on a semi-quantitative analysis by levels of B-HB in milk (µmol/l) using a commercial kit. BUN levels ranged between 11.74 and 15.92 mg/dl, being higher in fourth parity cows (p<0.05). The averages of total protein (6.54-7.90 g/dl) were homogeneous between calvings. The glucose values presented an inverse response, being lower in cows of third and fourth parity compared to cows of first and second parity (p<0.05). Similarly, the highest levels of milk production were observed in third parity cows (14.41 ± 5.42 l/d) and fourth parity (15.43 ± 4.36 l/d) with respect to first and second calvers (p<0.05). Body condition was lower in cows with subclinical ketosis. The calving - first heat interval and the pregnancy rate at first service were lower in cows with subclinical ketosis (p<0.05).

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