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Abadia Rojas J.R.,University of Veracruz | De Jesus Ruiz Lopez F.,National Research Center Disciplinaria en Fisiologia y Mejoramiento Animal | Vega Murillo V.E.,Research Center Regional Golfo Centro | Montaldo H.H.,National Autonomous University of Mexico
Revista Mexicana De Ciencias Pecuarias | Year: 2016

Methodology survival analysis model with Weibull proportional hazards was used to study Holstein cattle duration of functional productive life (FPL) in Mexico, using a model sire-maternal grandsire with Survival Kit V3.12 software. The FPL was calculated as the number of days between the date of first calving and the date of culling or censored, with a maximum credit of 305 d per lactation. The FPL was defined as the length of time between first calving and date of culling or death and a maximum of 305 d lactation. The data analyzed were obtained from the Holstein Association of Mexico. The final file consisted of 36,507 records for FPL of cows that calved for the first time between 1995 and 2008. The model included baseline hazard function of Weibull and the following fixed effects: age at first calving, lactation number by stage of lactation with cuts 29, 249 y 305 and standardized production level, with 10 classes with changes in each lactation period included as dependent variables and random effects of herd-year of calving and genetic effects of sire and maternal grandsire. Percentage of censored data was 25.54 %. All analyzed fixed effects were significant (P < 0.0001) and had a significant risk of animal culling influence. The heritability calculated logarithmic, original, effective and equivalent scales were 0.08, 0.13, 0.12 and 0.10 respectively, indicating that this character can effectively integrate breeding programs as has been done in other locations of Holstein cattle. Source

Abo-Donia F.M.,Egyptian Animal Production Research Institute | Abdel-Azim S.N.,Egyptian Animal Production Research Institute | Elghandour M.M.Y.,National Autonomous University of Mexico | Salem A.Z.M.,National Autonomous University of Mexico | And 3 more authors.
Tropical Animal Health and Production | Year: 2014

This study aimed to assess impacts of fungal treatment on the nutritional value of peanut hulls (PH) or urea at the rate of 5 kg/100 g of PH. Fermented sugar beet pulp inoculated with Trichoderma viride was supplemented to PH at rates of 5.0, 10.0 and 15.0 g/100 g air dry of PH andmixed well before aerobic incubation for 21 days. Organic matter (OM) content of PH declined with increased levels of fermented sugar beet pulp inoculums, while crude protein (CP), ether extract (EE), and ash increased. Fiber contents were decreased with both treatments of fermented sugar beet pulp and urea. Total N of PH increased with urea treatment, which reduced the true protein N to total protein N ratio. In sacco degradabilities of dry matter (DM), OM, and CP with urea treatment increased compared with fungal treatment. The DM intake of peanut hulls treated with fungus (PHF) was higher (P <0.05) than with peanut hulls treated with urea (PHU). Digestibility of OM, CP, neutral detergent fiber, and non-fiber carbohydrate by native breed Ossimi sheep with PH were higher (P <0.05) than with PH or urea treated PH. The intakes, losses, and balance of N increased (P <0.01) with PHF versus PH feeding. Feeding PHF increased (P <0.01) ruminal concentrations ofNH3-N, acetic acid, butyric acid, and the acetic to propionic acid ratio. Bacterial and protozoal counts increased (P <0.05) with feeding PHF or PHU versus PH. Overall, this fungal treatment of peanut hulls created a higher nutritive value feed for ruminants. © Springer Science+Business Media Dordrecht 2013. Source

Vargas-Velazquez A.D.,Metropolitan Autonomous University | Jimenez-Severiano H.,National Research Center Disciplinaria en Fisiologia y Mejoramiento Animal
Revista Mexicana De Ciencias Pecuarias | Year: 2016

To characterize the development of the epididymides, Barbados Blackbelly ram lambs were castrated at birth and every three weeks until wk 21 (n=4 to 6 per group). The individual epididymal weight was recorded; the three anatomical regions (caput, corpus and cauda) of the left epididymis were weighed, and samples taken for morphometric studies. The percentage of tubular tissue was calculated, as well as the tubular diameter, the width and area of the muscular layer, the height and area of the epithelium, and the diameter and area of the tubular lumen. Data were analyzed to determine differences among the anatomical regions and ages. The greatest growth of the whole organ was observed between 9 and 18 wk; the cauda started developing earlier than the other anatomical regions; the cauda was heaviest between birth and wk 12, but from 15 to 21 wk the caput and cauda weights were similar to each other. Overall, tubular diameter, width and area of the muscular layer, and luminal diameter and area were greatest in the cauda epididymidis. The epithelium height was greatest in the cauda until wk 9, but the situation reversed from wk 12 onwards. According to previous information for this breed, cauda started developing before the increase of circulating testosterone concentrations, and before the seminiferous tubule lumen appeared, whilst the caput and corpus development coincided temporally with the increase of testicular steroidogenic capacity and tubular fluid secretion. Such findings suggest differential requirements of endocrine and lumicrine stimulation for the normal development of the various anatomical regions of the epididymis. Source

Velazquez G.M.,Instituto Nacional de Investigaciones Nucleares | Zepeda A.B.,Instituto Nacional de Investigaciones Nucleares | Bermudez M.M.,National Research Center Disciplinaria en Fisiologia y Mejoramiento Animal | De Jesus Bustamante Guerrero J.,Instituto Nacional de Investigaciones Nucleares | And 3 more authors.
Revista Mexicana De Ciencias Pecuarias | Year: 2012

Data were collected between 2001 and 2003 from Guzerat (G), Criollo (C), Guzerat x Criollo (GC), and Criollo x Guzerat (CG) cows (n=208 records) to estimate heterosis (hi) and direct (gi) and maternal (gm) genetic effects for day of peak milk yield (DMP), maximum milk yield (PML), total milk yield (PTL), daily milk yield (PDL), persistency of lactation (PER), and to estimate relationships between PTL and weaning weight adjusted to 210 d of age (PA210). Lactation curve was estimated by the equation Y(n)=n/aekn. Variables were analyzed with least squares procedures and mixed models. Final models included effects of genotype of the cow, number, year and season of calving, sex of calf, birth weight as a covariate and two factor interactions. Correlations and regressions were estimated between PA210 and PTL. GC cows had greater production for PML, PTL and PDL (P<0.10) than C and G cows. hi was important (P<0.05) for PML, PTL and PDL. g i were favorable to G (P<0.05) for PML, PTL and PDL. Correlations were important (P<0.05) for all genetic groups. The regression coefficients were 0.044±0.014 (C), 0.037±0.014 (GC), 0.032±0.009 (G) and 0.027±0.015 (CG). Calves from C, GC, G and CG cows required 22.5, 27.3, 30.9 and 37.3 kg of milk per each kilogram of weight at weaning. The differences in the efficiency of utilization of milk consumed by calves suggest that different strategies of feeding during lactation should be considered for the production of feedlot calves with C, GC, G and CG cows. Source

Ortiz Rodea A.,National Autonomous University of Mexico | Barbosa Amezcua M.,National Autonomous University of Mexico | Partida de la Pena J.A.,National Research Center Disciplinaria en Fisiologia y Mejoramiento Animal | Gonzalez Ronquillo M.,National Autonomous University of Mexico
Journal of Applied Animal Research | Year: 2015

The present study constitutes a meta-analysis of the use of zilpaterol hydrochloride (ZH) in sheep production (18 studies, n = 724 animals were evaluated), focused in its effects on productive performance and carcass characteristics in sheep who were given ZH in different doses (control 0, ≤0.50 and ≥0.54 mg/kg raised to the power 0.75 body weight (BW)). The analysis of the data assembled in the database was conducted by a statistical meta-analysis based on mixed model methodology. Results on weight gain were higher (P < 0.03) for the group supplemented with ≥0.54 mg vs. control treatment, feed conversion improved (P < 0.01) with the inclusion of ZH compared with the control group. Carcass yield and Longissimus dorsi area showed no differences (P > 0.05) between treatments, fat content in the carcass diminished in a linear effect (P = 0.02) with the inclusion of ZH. The results show a positive effect on improving animal performance, mainly in the characteristics on the fat deposition. The optimal dose varies depending on the variable to improve, ranged in 0.24 up to 1.21 mg ZH/kg BW0.75 to reduce fat and carcass get leaner or increase average daily gain, respectively. © 2015 Taylor & Francis Source

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