Resposta à vermifugação seletiva em ovinos de diferentes raças sob pastejo contínuo nos trópicos úmidos

El objetivo fue evaluar la respuesta bajo un programa de desparasitación selectiva de ovejas Pelibuey (PB, n=12), Katahdin (KT, n=12), Pelibuey x Katahdin (PB:KT, n=15) y Pelibuey x Dorper (PB:DP, n=15) bajo pastoreo continuo sobre la excreción de huevos por gramo de heces (HPG), peso vivo (PV), condición corporal (CC), nivel de anemia (FAMACHA), hematocrito (Hto), hemoglobina (Hb) y la frecuencias de desparasitación. Las variables fueron evaluadas mediante un análisis de varianza considerando como tratamiento los grupos raciales (PB, KT, PB:KT y PB:DP) a través de los cuatro periodos de evaluación con medidas repetidas (días 20, 48, 76 y 104) en el tiempo y sus interacciones. Las frecuencias de desparasitación de las ovejas en cada categoría se analizaron mediante tablas de contingencia y pruebas de Chi cuadrada. Los valores de HPG fueron más altos (p<0.05) para las ovejas de los grupos raciales PB y PB:DP comparado a las ovejas KT y PB:KT. Contrariamente, las ovejas PB y PB:KT mostraron niveles mayores (p<0.05) de Hto comparadas con las ovejas KT y PB:DP. Sin embargo, los niveles de Hb encontrados fueron similares entre los grupos raciales evaluados. La proporción total acumulada revela que las ovejas PB:DP fueron las que mas requirieron (p<0.05) ser desparasitadas al menos una vez (32.8%). No se encontraron diferencias significativas entre los grupos raciales PB, KT y PB:KT. De acuerdo a los indicadores de PV, CC, Famacha, HPG, Hto, Hb y proporción de animales desparasitados durante el periodo evaluado, las ovejas del grupo racial PB:KT observaron el mejor comportamiento. Por tanto, la elección adecuada del mejor genotipo para condiciones de pastoreo combinado a un programa de desparasitación selectiva, puede contribuir significativamente en el control de nematodos gastrointestinales.The aim was to evaluate the response under a selective deworming program of Pelibuey (PB, n=12), Katahdin (KT, n=12), Pelibuey x Katahdin (PB:KT, n=15) and Pelibuey x Dorper (PB :DP, n=15) ewes under continuous grazing on the excretion of eggs per gram of feces (HPG), live weight (LW), body condition score (BCS), level of anemia (FAMACHA), hematocrit (Hto), hemoglobin (Hb ) and deworming frequencies. The variables were evaluated by means of an analysis of variance considering as treatment the racial groups (PB, KT, PB:KT and PB:DP) through the four evaluation periods with repeated measures (days 20, 48, 76 and 104) in time and their interactions. The deworming frequencies of the sheep in each category were analyzed using contingency tables and Chi-square tests. HPG values ​​were higher (p<0.05) for ewes from the PB and PB:DP breed groups compared to KT and PB:KT ewes. In contrast, PB and PB:KT ewes showed higher levels (p<0.05) of Hto compared to KT and PB:DP ewes. However, the Hb levels found were similar between the racial groups evaluated. The accumulated total proportion reveals that PB:DP ewes were the ones that most required (p<0.05) to be dewormed at least once (32.8%). No significant differences were found between the PB, KT and PB:KT racial groups. According to the indicators of LW, BCS, Famacha, HPG, Hto, Hb and proportion of dewormed animals during the evaluated period, the sheep of the PB:KT breed group observed the best behavior. Therefore, the adequate choice of the best genotype for grazing conditions combined with a selective deworming program can contribute significantly to the control of gastrointestinal nematodes

The reinsertion of controlled internal drug release devices in goats does not increase the pregnancy rate after short oestrus synchronization protocol at the beginning of the breeding season

Trabajo de investigación cuya temática es la sincronización del estro en ovejas de pelo.This study aimed to evaluate the effect of reinserting controlled internal drug release (CIDR) devices after fixed-time artificial insemination (FTAI) on pregnancy rates in goats. Oestrus was synchronized with a short (5 days) CIDR protocol, and FTAI was conducted 54 hours after CIDR removal. According to the reinsertion of CIDR after FTAI, goats were assigned to three treatments: G0 control group (n = 29), no CIDR reinsertion; G7 group (n = 27), CIDR reinserted 7 days; G14 group (n = 29), CIDR reinserted 14 days. Blood samples were collected to determine progesterone levels. Oestrus appearance (92.9%), interval of CIDR removal to oestrus (IRE = 34.1 ± 1.1 hours), interval of oestrus onset to artificial insemination (IEAI = 20.2 ± 1.0 hours), mean duration of oestrus (38.4 ± 1.4 hours), and pregnancy rates (61.0%) were similar (P > .05) among groups. Progesterone concentrations were higher (P  .05) for all groups. In conclusion, reinsertion of CIDR for 7 or 14 days after a short oestrus synchronization protocol and FTAI did not increase the overall pregnancy rate of goats

Desempeño productivo y análisis económico de una engorda intensiva de corderos tratados con zeranol y andrógenos inyectable bajo condiciones tropicales

The aim of this study was to compare the productive performance and profitability of the fattening of Kathadin male and female lambs (n=97) in confinement treated with Zeranol (ZNL), androgens (AND) and ZNL+AND under a 2x4 factorial design. The lambs treated with ZNL received 0.2 mg/kg of body weight (BW) every 28 d, those treated with AND received Nandrolone Decanoate + Trenbolone + Boldenone Undecinelate, via IM in doses of 0.3 mg/kg + 0.4 mg/kg + 0.3 mg/kg of BW, respectively, every 28 d, those treated with ZL+AND received the same doses of the mentioned drugs, while those in the control group received 0.5 mL of saline solution. Final body weight (FBW), daily weight gain (DWG), feed conversion (FC) on dry basis (DM) and wet basis (WM), and voluntary intake (VC) in DM and WM were evaluated. The FBW was different (p<0.05) between treatments in males and females. The DWG was higher (p<0.05) for females treated with AND compared to those treated with ZNL and AND+ZNL, the latter being similar to those of the control group. Females treated with AND registered a lower (p<0.05) VC compared to those treated with ZNL and AND+ZNL. Net utility, benefit: cost ratio and profitability were better in animals treated with AND. The administration of AND represents a viable alternative to make more efficient the confinement fattening systems of lambs.El objetivo del estudio fue comparar el desempeño productivo y la rentabilidad de una engorda de corderos machos y hembras Kathadin (n=97) en confinamiento tratados con Zeranol (ZNL), andrógenos (AND) y ZNL+AND bajo un diseño factorial 2x4. Los corderos tratados con ZNL recibieron 0.2 mg/kg de peso vivo (PV) cada 28 d, los tratados con AND recibieron Decanoato de nandrolona + Trembolona + Undecinelato de boldenona, vía IM en dosis de 0.3 mg/kg + 0.4 mg/kg + 0.3 mg/kg de PV, respectivamente, cada 28 d, los tratados con ZL+AND recibieron las mismas dosis de los fármacos mencionados, en tanto que los del grupo control recibieron 0.5 ml de solución salina. Se evaluó el peso vivo final (PVF), ganancia diaria de peso (GDP), conversión alimenticia (CA) en base seca (BS) y base húmeda (BH), y el consumo voluntario (CV) en BS y BH. El PVF fue diferente (p<0.05) entre tratamientos en hembras y machos. La GDP resultó mayor (p<0.05) para hembras tratadas con AND en comparación con las tratadas con ZNL y AND+ZNL, siendo las últimas similares a las del grupo control. Las hembras tratadas con AND registraron un menor (p<0.05) CV en comparación con las tratadas con ZNL y AND+ZNL. La utilidad neta, relación beneficio: costo y rentabilidad fueron mejores en los animales tratados con AND. La administración de AND representa una alternativa viable para hacer más eficiente los sistemas de engorda de corderas y corderos en confinamiento

Changes in air quality in Mexico City, London and Delhi in response to various stages and levels of lockdowns and easing of restrictions during COVID-19 pandemic

The impacts of COVID-19 lockdown restrictions have provided a valuable global experiment into the extent of improvements in air quality possible with reductions in vehicle movements. Mexico City, London and Delhi all share the problem of air quality failing WHO guideline limits, each with unique situations and influencing factors. We determine, discuss and compare the air quality changes across these cities during the COVID-19, to understand how the findings may support future improvements in their air quality and associated health of citizens. We analysed ground-level PM10, PM2.5, NO2, O3 and CO changes in each city for the period 1st January to August 31, 2020 under different phases of lockdown, with respect to daily average concentrations over the same period for 2017 to 2019. We found major reductions in PM10, PM2.5, NO2 and CO across the three cities for the lockdown phases and increases in O3 in London and Mexico City but not Delhi. The differences were due to the O3 production criteria across the cities, for Delhi production depends on the VOC-limited photochemical regime. Levels of reductions were commensurate with the degree of lockdown. In Mexico City, the greatest reduction in measured concentration was in CO in the initial lockdown phase (40%), in London the greatest decrease was for NO2 in the later part of the lockdown (49%), and in Delhi the greatest decrease was in PM10, and PM2.5 in the initial lockdown phase (61% and 50%, respectively). Reduction in pollutant concentrations agreed with reductions in vehicle movements. In the initial lockdown phase vehicle movements reduced by up to 59% in Mexico City and 63% in London. The cities demonstrated a range of air quality changes in their differing geographical areas and land use types. Local meteorology and pollution events, such as forest fires, also impacted the results

Genes con efecto mayor sobre la fertilidad de ovejas. Revisión

The genetic  study on sheep breeds  with naturally high ovulation  rate  (OR) and  prolificacy, has allowed to  detect theparticipation  of  several  genes.  Among  them  there  are  the  ones  related  to  the  transforming  growth  factor-betasuperfamily  (BMPRIB,  GDF9  and  BMP-15),  as  well  as  to  other  genes  with  major  effect,  such  as  the  distal-lesshomeobox  3’  (FecL),  estrogen  receptor  (ESR),  prolactin  receptor  (PRLR)  and  inhibin  receptor  (INHA  and  INHB).However,  sheep  homozygous  for  the  majority  of  the  allelic  variants  in  BMP-15  or  GDF9  are  sterile,  for  which  it  isimportant  the  understanding  of  the  genetic  and  molecular  basis  of  these  polymorphisms,  for  their  use  in  rationalprograms  of  genetic  improvement  on  prolificacy.  Polymorphism  in  the  melatonin  gene  (MTNR1)  has  been associatedwith  non-reproductive  seasonality in  sheep.  Selecting several  sheep  breeds for  these characteristics  has significantlyreduced  the  seasonal anoestrus,  showing reproductive  activity during  spring and  summer. It seems that  these  genesin  some  breeds  may  be  interacting  additively  and  an  allelic  variant  in  a  breed  may  not  be  present  in  other,  or  twobe  present  at  the same  time;  therefore, the  understanding of  the genetic  mechanisms  that affect  ovulation  rate  andprolificacy  are  important  for  the  selection  of  reproductive  traits.El estudio genético en razas de ovejas que naturalmente presentan altas tasas de ovulación (TO) y de prolificidad, ha permitido detectar la participación de varios genes. Entre ellos están los relacionados a lasuperfamilia del factor de crecimiento transformante B (BMPRIB, GDF9 y BMP-15), así como de otros genes con efecto mayor, tales como el “distal-less homeobox 3” (FecL), el receptor de estrógenos (ESR), el receptor de prolactina (PRLR) y el de las inhibinas (INHA y INHB). Sin embargo, las ovejas homocigotas para la mayoría de las variantes alélicas en BMP-15 o GDF9 son estériles, por lo que es importante el entendimiento de las bases genéticas y moleculares de estos polimorfismos, para su uso en programas racionales de mejoramiento genético con énfasis en la prolificidad. El polimorfismo en el gen de la melatonina (MTNR1) se ha asociado con la no estacionalidad reproductiva en ovejas. La selección en varias razas de ovejas para estas características ha reducido significativamente el anestro estacional, mostrando actividad reproductiva durante la primavera y el verano. Sin embargo, parece ser que estos genes en algunas razas pueden estar interactuando aditivamente, y una variante alélica en una raza puede no aparecer en otra, o bien dos al mismo tiempo, por lo que son variados los mecanismos genéticos que afectan la tasa ovulatoria y prolificidad

Producción de leche en vacas de doble propósito tratadas conoxitocina bajo condiciones de trópico húmedo mexicano

Research employing crossbred cows (½, ¾ and 7/8 B. Taurus x B. indicus) during the first 60 d of lactation was carried out at three commercial dairies, where feeding is based fundamentally on rotational grazing of tropical grasses. Supplemental feeding of the cows and their calves varied among the herds, but consisted mainly of mineral salts, poultry litter and other local resources. Two treatments related to the milking procedures were compared at each site. At Rancho Los Rejones (RLR) 11 cows per group were subjected to either: no stimulation to milk letdown other than that involved in routine 2x/d mechanical milking (control) or injection of 8 IU of oxytocin (OT) a.m. and p.m., three quarters being milked and the other left to be suckled by the calf. At Rancho Las Palmas (RLP) and Rancho La Isla (RLI) the 60-d period was divided into four successive 15-d phases. At RLP two groups of nine cow alternated by phase between the treatments: 8 IU/d of OT at the sole daily mechanical milking of three quarters or dummy insertion of a hypodermic needle without hormone (HN). At RLI one group of six cows received teat simulation by the calf (CS) prior to hand milking and six others received 10 IU/d of OT during two 15-d phases, alternating with CS in the other two phases. Milk production (kg/d) responded more to OT use than to routine stimulation at RLR (8.46 vs. 4.28, P<0.01), to HN at RLP (4.07 vs. 2.73, P<0.001) or to CS at RLI (8.58 vs. 5.48, P<0.05). At RLR body condition score of the cows did not differ between treatments, but at RLI use of OT resulted in greater weight loss than CS (51.08 vs. 17.24 kg). Weight gain of the calves (g/d) of cows treated with OT was slightly higher at RLR (381 vs. 328), but lower at RLP (252 vs. 333) and especially at RLI (561 vs. 719, P<0.01) relative to non-use of the exogenous hormone. In conclusion, the use of OT in early lactation improved milk yield, but it can also result in weight loss by the dam and reduced weight gain by the calf, to the detriment of double purpose operations.Se realizó experimentación usando vacas cruzas (½, ¾ and 7/8 B. taurus x B. indicus) durante los primeros 60-d de lactancia en tres ranchos comerciales donde la alimentación se basa fundamentalmente en pastoreo rotativo de gramíneas tropicales. La alimentación suplementaria de las vacas y sus crías varió entre los tres hatos, pero constó mayormente de sales minerales, pollinaza y otros recursos locales. Se compararon dos tratamientos relacionados con el ordeño en cada lugar. En Rancho Los Rejones (RLR) se sometieron 11 vacas por grupo a los tratamientos: ningún estímulo para la eyección de la leche en adición al rutinario del ordeño mecánico 2 x/d (control) o inyección de 8 UI de oxitocina (OT) a.m. y p.m., ordeñándose tres pezones y dejando el otro para la cría. En Rancho Las Palmas (RLP) y Rancho La Isla (RLI) se dividió al período de 60 d en cuatro sucesivos lapsos de 15. En RLP se alternaron por lapso dos grupos de nueve vacas entre los tratamientos: 8 UI/d de OT al ordeño mecánico único del día de tres pezones o la inserción de una aguja hipodérmica sin inyectar hormona (AH). En RLI un grupo de seis vacas recibió el estímulo de la cría sobre los pezones (EC) antes del ordeño manual y otras seis recibieron 10 UI/d de OT durante dos lapsos de 15 d, alternando con EC en los otros dos. La cosecha de leche (kg/D) respondió mejor al uso de OT que al estímulo rutinario en RLR (8.46 vs. 4.28, P<0.01), a AH en RLP (4.07 vs. 2.73, P<0.001) o a EC en RLI (8.58 vs. 5.48, P<0.05). En RLR la puntuación de condición corporal de las vacas no difirió entre tratamientos, pero en RLI el uso de OT resultó en mayor pérdida de peso materno que el EC (51.08 vs. 17.24 kg). La ganancia de peso de las crías (g/d) de vacas tratadas con OT fue levemente mayor en RLR (381 vs. 328), pero menor en RLP (252 vs. 333) y RLI 561 vs. 719, P<0.01) relativo al no uso de la hormona exógena. En conclusión, el uso de OT en lactación temprana promovió mayor producción de leche vendible, pero puede a la vez resultar en pérdida de peso corporal de la vaca y ganancias de peso menores en las crías, efecto adverso en un sistema doble propósito

Ovulatory response and embryo quality in Katahdin ewes supplemented with palm oil

The aims of this study were to evaluate the superovulatory response (SR), embryo quality and embryonic development in Katahdin ewes that received a dietary supplement of palm oil (PO). Ten ewes were assigned to receive 35 g palm oil (n = 10, PO3) and 10 to receive 70 g palm oil (n = 10, PO6) for 25 days. On day 0, the ewes were synchronized with 0.3 mg progesterone-releasing devices (CIDR-G®). From days 6 to 9, the donors were superovulated with 200 mg follicle-stimulating hormone (FSH) (Folltropin-V®) at decreasing doses every 12 hours (40 - 40, 30 - 30, 20 - 20 and 10 - 10 mg/ewe). On day 8, the devices were removed and donors were mated twice with fertile rams at 12-h intervals. Seven days after mating, the embryos were recovered and evaluated for their stage of development and quality grade (1 = excellent, 2 = good, 3 = bad and 4 = degenerated). In addition, on days 0, 7 and 15, blood samples were taken to determine cholesterol, triglycerides, insulin and insulin-Iike growth factor-1 (IGF-1) concentrations in serum blood. Using chi-square and t-tests, the superovulatory response (SR), ovulation rate (OR), total embryonic structures (TES), transferable embryos (TE), degenerated embryos (DEs) and developmental stage and quality were evaluated. No significant differences were observed between treatments for SR, OR, TES and TE variables or for cholesterol, triglycerides, insulin and IGF-1 concentrations. There were differences in the numbers of DE, as well as a trend for more homogeneous developmental stage in the embryos of ewes supplemented with PO6, as well as a higher number of quality 1 embryos and lower numbers of quality 3 and 4 embryos. Palm oil supplementation could be a recommendable practice to improve the quality of embryos and homogenous developmental stage (morula and blastocyst).Keywords: Fatty acids, ovarian activity, shee

Efecto del aceite de palma sobre el crecimiento y capacidad reproductiva de carneros de pelo púberes

The average daily gain (GDP), semen quality, libido, and serviceability in 8 hair rams (Black Belly × Kathadin and Pelibuey × Kathadin) supplemented with rations containing a 3 % of palm oil (AP) or animal fat (GA) were studied during 120 days. During the first 60 days, lambs were fed with 300 g/animal/d of a diet with 3 % of animal fat and, the following 60 days, each lamb received 500 g of feed. In the experimental group GA was replaced by AP. The average daily weight gain (GDP), body condition score (CC), scrotal circumference (CE), thoracic perimeter (PT), height at withers (AC) and length from the withers to the rump (LCG) were evaluated. The seminal quality was evaluated from 6 months of age and average weight of 26.0 kg. During seven weeks, the volume, concentra- tion, mass motility, individual primary abnormalities and living sperm percentage were assessed. To evaluate the libido and capacity of mating, the males were placed for 15 minutes with estrogenized females; number of mounts (NM), number of servi- ces (NS), number of mounts by service (NMS), reaction time (TR) to matings (1M, 2M, 3M) and services (1S, 2S, 3S), were recorded. The varia- bles were analyzed by ANOVA. There were no differences among AP and GA for the evaluated variables for PV, GDP, PT, CC, AC, and LCG. Semen quality, libido and serving capacity were similar. The number of services and reaction times for mount and service were also similar for both treatments, however diferents were observed in the number of mounts and so in number of mounts by service. The AP is an energetic alternative that can be considered in the feeding of rams in the tropics without affecting growth, the seminal quality and libido.Se evaluó la ganancia diaria de peso (GDP), calidad seminal, libido y capacidad de servicio en carneros de pelo, bajo pastoreo y suplementados con raciones conteniendo un 3 % de aceite de palma (AP) o grasa animal (GA). Se utilizaron ocho corderos Black Belly × Kathadin y Pelibuey × Kathadin. A los animales se les suministró durante los primeros 60 días, 300 g por cabeza de una ración con 3 % de GA, cantidad que se elevó a 500 g desde los 60 a los 120 días. En el grupo expe- rimental GA se sustituyó por la misma proporción de aceite de palma. Cada 14 días se evaluó el peso vivo (PV), GDP, condición corporal (CC), circun- ferencia escrotal (CE), perímetro torácico (PT), altura a la cruz (AC) y largo de la cruz a la grupa (LCG). La calidad seminal se evaluó a partir de los 6 meses de edad con un peso promedio de 26,0 kg. Durante siete semanas, se evaluó el volumen, concentración, motilidad masal e individual, % de anormalidades primarias y % de espermatozoides vivos. La libido y capacidad de monta se valoró con hembras estrogenizadas registrando el nú- mero de montas (NM), el número de servicios (NS), el número de montas por servicio (NMS), tiempo de reacción (TR) a las sucesivas montas (1M, 2M, 3M) y servicios (1S, 2S y 3S). Las variables se analizaron mediante un ANOVA. No se registraron diferencias entre AP y GA para las variables PV, GDP, PT, CC, AC y LCG. La calidad seminal, libido y capacidad de servicio fueron similares en ambos tratamientos. El número de servicios y el tiempo de reacción a la monta o al servicio fueron similares en ambos tratamientos sin embargo se observa- ron diferencias en el número de montas lo que se reflejó en el número de montas por servicio. El aceite de palma es una alternativa energética para la alimentación de carneros en el trópico que no afecta al crecimiento, calidad seminal y libido