Sperm morphology is essential in evaluating seminal quality and important for fertility prediction in breeding males. The aim of this study was to compare the morphometric parameters of alpaca sperm, collected using three methods of semen extraction, recovery of the vas deferens (DCD), electro ejacula-tion (EE) and vaginal aspiration (VA). The collection was made of 3 animals by each method. The mobility, concentration, vitality, membrane functionality and sperm morphometry parameters were determined in a computerized semen analysis kit – ISAS® CASA - Morph. For morphometric parame-ters, semen samples were processed with a Hemacolor® staining kit and viewed under a phase-contrast microscope. For each sample, at least 200 sperm were captured at random, with an image resolution of 0.08 µm per pixel on the horizontal and vertical axes. The comparison of the morphometric parameters between the collection method and the animal was carried out using a random block design. Total motil-ity was 16.27±11.96%, 14.68±11.21% and 12.44±7.27%; the sperm concentration of 247±186.70x106EPZ/mL, 67.92±67.92x106EPZ/mL and 100.32±56.13x106EPZ/mL, the vitality was 62.86 ±15.92%, 63±15.21% and 70.16±14.33% in sperm collected by DCD, EE and AV respectively. Regarding the morphometric parameters, a length of 5.49±0.43µm, 5.53±0.41µm and 5.75±0.53µm was found, area 14.30±2.00 µm2, 15.05±1.77 µm2 and 15.88±2.00 µm2, perimeter of 16.10±1.31µm, 17.11±1.20µm and 17.41 ± 1.43, width of 3.22±0.27µm, 3.30±0.32µm and 3.33±0.25µm and the acrosome percentage of 52.22±7.82µm, 49.52±7.47µm and 47.44±5.77µm in sperm collected by DCD, EE and AV respectively. The morphometric parameters of the size and shape of the sperm head and the intermediate piece showed significant statistical differences (p <0.01) between the collection methods and between the animals. In conclusion, the morphometric parameters of alpaca spermatozoa were influenced by collection method, and show variations between animals.

La morfología espermática es esencial en la evaluación de la calidad seminal e importante para la pre-dicción de la fertilidad de machos reproductores. El objetivo del presente estudio fue comparar los parámetros morfométricos de espermatozoides de alpaca, obtenidos por tres métodos de extracción de semen, la recuperación del conducto deferente (DCD), electroeyaculación (EE) y aspiración vaginal (AV). La colección se realizó de 3 animales por cada método. Se determinó la movilidad, concentra-ción, vitalidad, funcionalidad de membrana y parámetros de morfometría espermática, con un equipo de análisis computarizado de semen - ISAS® CASA - Morph. Para los parámetros morfométricos, las muestras de semen se procesaron con un kit de tinción Hemacolor® y se observaron en un microscopio de contraste de fases. Por cada muestra, se capturaron al menos 200 espermatozoides al azar, con resolución de imágenes de 0.08 μm por píxel en los ejes horizontal y vertical. La motilidad total fue de 16.27±11.96%, 14.68±11.21% y 12.44±7.27%, la concentración espermática de 247±186.70 x 106EPZ/mL, 67.92±67.92 x 106EPZ/mL y 100.32±56.13 x 106EPZ/mL, la vitalidad fue 62.86±15.92%, 63±15.21% y 70.16±14.33% en espermatozoides colectados por DCD, EE y AV respectivamente. En cuanto a los parámetros morfométricos se encontró una longitud de 5.49±0.43 µm, 5.53±0.41µm y 5.75±0.53µm, área 14.30±2.0µm2, 15.05±1.77µm2 y 15.88±2.0µm2, perímetro de 16.10±1.31µm, 17.11±1.20µm y 17.41±1.43µm, ancho de 3.22±0.27µm, 3.30±0.32µm y 3.33±0.25 µm y el porcentaje de acrosoma de 52.22±7.82%, 49.52±7.47% y 47.44±5.77% en espermatozoides colectados por DCD, EE y AV respectivamente. La comparación de los parámetros morfométricos entre método de colecta y animal se realizó mediante un diseño de bloques alzar. Los parámetros morfométricos del tamaño y forma de la cabeza de espermatozoide, y pieza intermedia mostraron diferencias estadísticas significati-vas (p<0.01) entre métodos de colección y entre animal. En conclusión, los parámetros morfométricos del espermatozoide de alpaca son influidos por el método de colección, y muestran variación entre animales.

Peru has the largest inventory of alpacas worldwide. Despite their importance as a source of net income for rural communities living at the Andean Plateau, data on energy requirements and methane (CH4) emissions for alpacas are particularly lacking. In 2019, the International Panel on Climate Change (IPCC; 2006, and Refinement 2019) outlined methods for estimating CH4 emissions from enteric fermentation and no methane (CH4) conversion factors were reported for camelids. IPCC has since updated its guidelines for estimating CH4 emissions from the enteric fermentation of livestock at a national scale. For greenhouse gas (GHG) inventory purposes, conversion factors were developed for ruminants but not for domestic South American camelids (SAC), with this category including alpacas. A mobile open-circuit respirometry system (head hood) for the rapid determination of CH4 and CO2 production, O2 consumption, and thereafter, heat production (HP) for camelids was built and validated. In addition, an experimental test with eight alpacas was conducted for validation purposes. The average HP measured by indirect calorimetry (respiratory quotient (RQ) method) was close to the average HP determined from the carbon–nitrogen balance (CN method); 402 kJ/kg BW0.75 and 398 kJ/kg BW0.75, respectively. Fasting HP was determined by the RQ method and 250 kJ/kg BW0.75 was obtained. The metabolizable energy requirement for maintenance (MEm) was calculated to be 323 kJ/kg BW0.75 with an efficiency of energy utilization of 77%. When intake was adjusted to zero energy retention by linear regression, the MEm requirement increased to 369 kJ/kg BW0.75 and the efficiency decreased up to 68%. The CH4 conversion factor (Ym) was 5.5% on average. Further research is required to gain a better understanding of the energy requirements and CH4 emissions of alpacas in conditions of the Andean Plateau and to quantify them with greater accuracy.

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