Abelardo Correa-Calderón

Crecimiento y características de canal en corderos Pelibuey puros y cruzados F1 con razas Dorper y Katahdin en confinamiento.

The aim of this study was to evaluate feedlot performance and carcass characteristics of 36 male and female lambs from the genotypes pure Pelibuey, Dorper x ...

Pelibuey Ewe Productivity and Subsequent Pre-weaning Lamb Performance Using Hair-sheep Breeds Under a Confinement System

Abstract Macías-Cruz, U., Álvarez-Valenzuela, F.D., Correa-Calderón, A., Molina-Ramírez, L., González-Reyna, A., Soto-Navarro, S. and Avendaño-Reyes, L. 2009. Pelibuey ewe productivity and subsequent pre-weaning lamb performance using hair-sheep breeds under a confinement system. J. Appl. Anim. Res., 36: 255–260. The purpose of this study was to evaluate the effect of hair sheep sires on reproductive performance of Pelibuey ewes and to compare pre-weaning growth traits of their offspring. Forty-three Pelibuey ewes were randomly distributed in 3 groups to be mated by 3 breed sires (Dorper, Dr; Katahdin, Ka and Pelibuey, Pb). Fertility, fecundity and prolificacy were similar (P>0.05) among the three breed sires. In ewes mated to Dr, gestation length was 1.8 and 3.3 d shorter (P<0.01) than those mated to Ka or Pb sires, respectively. Birth weight, weaning weight and average daily gain up to weaning were higher among single born Ka lambs. Weaning litter weight per ewe lambing was greater (P<0.04) in ewes mated to Dr and Ka sires. In conclusion, Pelibuey ewes under a confinement system crossed with Dr or Ka sires improved their reproductive efficiency; moreover, pre-weaning traits of their lambs were also improved.

Thermoregulation of nutrient-restricted hair ewes subjected to heat stress during late pregnancy.

In summers with severe hot environmental temperatures, thermoregulation is expected to be critical during the last third of gestation of hair ewes, and this effect can be overstated by suboptimal feeding conditions. Twenty-four multiparous hair sheep ewes with approximately 100d of pregnancy were randomly assigned to two treatments to evaluate the effects of nutritional restriction (NR) during late gestation on some serum metabolites, physiological variables, and thyroid hormone concentrations under intense heat load (maximum temperature 42-45°C). Treatments were as follows: (1) control, ewes fed free choice wheat straw plus a concentrate at a rate of 500g/d, and (2) nutritionally-restricted (NR) ewes, which were offered wheat straw only ad libitum. Body weight of NR ewes dropped 5.1kg (P<0.05), while control ewes gained 4.7kg during the study period. Rectal temperature was not affected (P>0.05) by feeding regime either in the morning or afternoon hours. Respiration rate was greater (P<0.05) in control ewes (20 and 40breaths/min higher in the day and night, respectively) on d 130 and 145 of pregnancy compared to NR ewes. Skin temperatures during the morning and afternoon were affected (P<0.05) by feeding regime at d 130 and 145 of pregnancy. In the morning, NR ewes presented greater (P<0.05) head and rump temperature at day 145 of gestation, and lower (P<0.05) udder temperatures at d 130 and 145 than control ewes. In the afternoon, skin temperatures of NR ewes were higher (P<0.05) in head and right flank on d 130 and 145 of pregnancy, and in udder at day 145 compared to control ewes. Serum glucose was higher (P<0.05) in NR ewes than control animals at day 145 of pregnancy. Serum cholesterol, triglyceride and thyroid hormones were not affected by nutritional restriction. Overall, it was found that nutritionally restricted ewes were less affected by intense heat loads than well-fed ewes, apparently due to the lower metabolic heat produced by this underfed animals. Also, it was apparent that the lower respiration rate of NR ewes was compensated by a greater body surface temperature.

Behavioural, follicular and hormonal characteristics of the oestrous cycle of Mexican Criollo cattle

The objective of the present study was to describe the behavioural, ovarian and hormonal characteristics of the oestrous cycle of Criollo cattle. Twenty-two cycling cows subjected to oestrus synchronisation were used to take blood samples every 4 h, to determine luteinising hormone (LH) until ovulation was detected by ultrasound and then every 24 h until the subsequent naturally occurring ovulation to determine progesterone concentrations. At the onset of synchronised oestrus, ovaries were examined by ultrasound every 8 h to determine dominant follicles until ovulation was detected, and daily afterwards to observe ovarian dynamics until the onset of the subsequent spontaneous behavioural oestrus. Time from oestrus to ovulation was higher in synchronised than in spontaneous oestrus (P < 0.01). Time from LH surge to ovulation was 40.5 h. When two- and three-wave cycles were compared, inter-ovulatory intervals were similar, growth rate of the preovulatory follicle was lower in two-wave cycles, time from onset of ovulatory wave to ovulation was higher in cycles with two waves and time from oestrus to ovulation was higher in three-wave cycles (P < 0.01). Corpus luteum volume averaged 1.3 cm3 and progesterone concentration peaked at an average 6.5 ng/mL. LH peak averaged 33.5 ng/mL during oestrus in all cows. Ovulatory follicle diameter ranged from 8 to 12 mm in either two- or three-wave cycles. Results suggested that overall times from oestrus and LH peak to ovulation are longer in Criollo cows than those in other breeds. This, along with information about growth rate, size and age of ovulatory follicles, may have implications for reviewing the optimum time for artificial insemination and how reproductive technologies are applied to Criollo cattle.

Buffel grass (Cenchrus ciliaria L.) substitution for orange pulp on intake, digestibility, and performance of hairsheep lambs

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.

Reproductive Behavior and Efficiency in Pelibuey Ewes Treated with FGA-PMSG and Bred by Mounting or Laparoscopic Intrauterine Insemination

Abstract Quintero-Elisea, J.A., Vázquez-Armijo, J.F., Cienfuegos-Rivas, E.G., Correa-Calderón, A., Avendaño-Reyes, L., Macías-Cruz, U., Lucero-Magaña, F.A. and González-Reyna, A. 2010. Reproductive behavior and efficiency in Pelibuey ewes treated with FGA-PMSG and bred by mounting or laparoscopic intrauterine insemination. J. Appl. Anim. Res., 38: 13–16. To evaluate the effect of 200 IU of PMSG on reproductive behaviour of hair sheep ewes were bred by 1) intrauterine artificial insemination by laparoscopy (IAIL) or 2) natural mount (NM) in Northeast Mexico, and subjected to an estrus synchronization protocol, with fluorogestone acetate sponges for 10 d (40 mg, FGA). Twenty four hours before sponge withdrawal, the ewes were randomly assigned to one of two treatments, T1= 200 IU of PMSG (n= 40) IM or T2= 0 IU of PMSG (n=20). Ewes showing estrus, were divided in two groups, to be served by 1) MN or 2) by IAIL. The PMSG treatment reduced(P<0.0001)hours to estrus (HE) (25.8 h vs 37.7 h). The conception rate (CR) was smaller(P<0.05)in the PMSG treated ewes. In addition, the lambing rate (LR) and the fecundity (Fc) were smaller (P<0.05) in the ewes of the control group. The CR was lesser (P<0.05) for the IAIL group. The LR was lesser (P<0.05) in the ewes of the NM group. PMSG reduced the hours to estrus and increased the lambing rate; however, it will be necessary to determine the effect of PMSG dose, on the reproductive efficiency of the ewes. It is recommended to use an FGA+PMSG treatment for inducing the estrus, accompanied with IAIL to increase reproductive rate in hair sheep ewes.

Prediction of rectal temperature using non-invasive physiologic variable measurements in hair pregnant ewes subjected to natural conditions of heat stress

Rectal temperature (RT) is the foremost physiological variable indicating if an animal is suffering hyperthermia. However, this variable is traditionally measured by invasive methods, which may compromise animal welfare. Models to predict RT have been developed for growing pigs and lactating dairy cows, but not for pregnant heat-stressed ewes. Our aim was to develop a prediction equation for RT using non-invasive physiological variables in pregnant ewes under heat stress. A total of 192 records of respiratory frequency (RF) and hair coat temperature in various body regions (i.e., head, rump, flank, shoulder, and belly) obtained from 24 Katahdin × Pelibuey pregnant multiparous ewes were collected during the last third of gestation (i.e., d 100 to lambing) with a 15 d sampling interval. Hair coat temperatures were taken using infrared thermal imaging technology. Initially, a Pearson correlation analysis examined the relationship among variables, and then multiple linear regression analysis was used to develop the prediction equations. All predictor variables were positively correlated (P<0.01; r=0.59-0.67) with RT. The adjusted equation which best predicted RT (P<0.01; Radj(2)=56.15%; CV=0.65%) included as predictors RF and head and belly temperatures. Comparison of predicted and observed values for RT indicates a suitable agreement (P<0.01) between them with moderate accuracy (Radj(2)=56.15%) when RT was calculated with the adjusted equation. In general, the final equation does not violate any assumption of multiple regression analysis. The RT in heat-stressed pregnant ewes can be predicted with an adequate accuracy using non-invasive physiologic variables, and the final equation was: RT=35.57+0.004 (RF)+0.067 (heat temperature)+0.028 (belly temperature).

Comportamiento productivo, consumo de nutrientes y productividad al parto de ovejas de pelo suplementadas con energía en el preparto durante verano e invierno

Se utilizaron 48 ovejas multiparas gestantes para evaluar el efecto de la suplementacion energetica (100 y 125% de energia metabolizable) y la epoca (verano e invierno) sobre el comportamiento productivo y el consumo de nutrientes durante el ultimo tercio de gestacion, en un clima arido. Adicionalmente fue evaluada la productividad de la oveja al parto. Las dietas experimentales se ofrecieron del dia 100 de gestacion al parto. Las condiciones climaticas en verano fueron de estres calorico y en invierno termoneutrales. La interaccion suplementacion por epoca no fue significativa (P > 0,05) para ninguna variable. Las ovejas suplementadas comparadas con el grupo testigo presentaron mayor (P 0,05) el peso al nacimiento de los corderos y la productividad de la oveja al parto. Por lo demas, el consumo de nutrientes, la ganancia de peso y la eficiencia alimentaria fueron mayores (P 0,05) el peso al nacimiento pero si (P < 0,05) el tamano y peso de camada. En conclusion, la suplementacion energetica mejoro el consumo de energia, lo que se reflejo en un incremento en el peso vivo de la oveja pero no sobre el peso al nacimiento de las crias. Las altas temperaturas de verano redujeron la productividad de la oveja como resultado de un bajo consumo de nutrientes.

Efecto de época del año (verano vs. invierno) en variables fisiológicas, producción de leche y capacidad antioxidante de vacas Holstein en una zona árida del noroeste de México

El estres por calor (EC) induce la produccion de radicales libres derivados del oxigeno que se asocian con efectos negativos en la fisiologia, patologia y productividad de vacas lecheras. Con el proposito de medir y comparar variables fisiologicas y productivas de vacas Holstein en verano e invierno en una zona arida, se seleccionaron aleatoriamente 40 vacas lactantes (100 a 150 d en leche) en un mes representativo de cada epoca del ano (n = 20/ epoca). Los datos fueron analizados en un ANOVA bajo un diseno experimental completamente al azar, con epoca del ano como factor de interes (verano vs. invierno), y un nivel de significacion del 5%. Las temperaturas de la piel en costado derecho, nalga, ubre y cabeza, asi como de la leche, fueron 10 oC mas altas (P < 0,05) en verano. La tasa respiratoria fue dos veces mayor (106,87 ± 0,05 vs. 47,74 ± 0,06; P < 0,05) en verano, mientras que la temperatura rectal alcanzo 1,6 oC mas (P < 0,05) en verano. Las concentraciones de colesterol y TAS fueron menores (P < 0,05) en verano, mientras que la glucosa, TOS and IEO fueron mayores (P < 0,05) en la misma epoca. La produccion de leche se redujo en mas del 50% (P < 0,05) en verano, observandose reducciones de 42,6% en la produccion de energia en leche y de 48,4% en la produccion de leche ajustada a 3,5% de grasa. Se concluye que el efecto del EC es evidente y tiene un efecto perjudicial en la fisiologia y productividad de vacas Holstein en produccion, lo que hace necesario utilizar innovaciones ambientales para reducir este impacto negativo de las altas temperaturas

Effect of short-term cooling on physiological and productive responses of primiparous Holstein cows exposed to elevated ambient temperatures

Abstract To evaluate effects of short periods of cooling on physiological and productive parameters during summer, 27 first parity cows were grouped into control, 1 h cooling (C); 2 h cooling (AM); and 4 h cooling (AM+PM). The cooling system consisted of misting and forced ventilation. Skin temperatures were lower (P<0.05) in the AM+PM group during the morning but higher (P<0.01) in the afternoon, compared to C and AM groups. The respiratory rate was lower (P<0.01) in the AM+PM group than in C and AM groups. Rectal temperature, milk production, milk protein, and milk energy output were similar among the groups. Conversely, milk fat was higher (P<0.05) in AM+PM cows. Because use of a 4 h cooling period enhanced some physiological parameters and milk fat in primiparous Holstein cows, we recommend increasing the cooling period in arid regions to achieve higher performance and comfort of dairy cows.