Browsing by Autor "Atsuko Ikeda"

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Comportamiento productivo y reproductivo de vacas Nelore de diferentes edades en un sistema a pastoreo del trópico boliviano
(Universidad Técnica de Manabí, 2019) Atsuko Ikeda; Juan Pablo Garzón; Edis Macías Rodríguez; Pablo Roberto Marini
Productive and reproductive behavior of Nelore cows of different ages in a grazing system of the Bolivian tropics Resumen El objetivo del trabajo fue evaluar el comportamiento productivo y reproductivo de vacas adultas y en crecimiento de la raza Nelore en condiciones de pastoreo del trópico boliviano. El trabajo de investigación se realizó de octubre de 2016 a octubre de 2017 en la Hacienda Ganadería E7, Santa Cruz, Bolivia. Se utilizaron 100 vacas para el estudio. Se dividieron en dos grupos: Grupo adulto: GA, 28 vacas ≥ 5 años de edad y Grupo en crecimiento: GC, 72 vacas ≤ 5 años de edad. Los pesos entre ambos grupos analizados para GA y GC mostraron diferencia entre ellas (p≤0,05) durante todo el ensayo. Las vacas adultas tuvieron los menores intervalo parto-parto (GA: 380±28; GC: 506 ±18 días, p≤0,003), El estado corporal entre ambos grupos analizados también mostró diferencias entre los grupos (p≤0,05) el mejor estado corporal (GA: 2,4±0,06; GC: 2,2±0,02, p≤0,002), el mayor peso vivo adulto (GA: 461 ±7; GC: 418±5 kg, p≤0,0001) y mayor peso del ternero sin mostrar diferencias p≥0,05 (GA: 34,1±0,8; GC: 32,3±0,5 kg). Se concluye que las vacas adultas poseen un mejor comportamiento productivo y reproductivo, y además sería importante mantener en el rodeo un porcentaje mayor de ellas para los sistemas estudiados. Palabras clave: peso adulto; estado corporal; intervalo parto-parto: peso el ternero al nacimiento Abstract The objective of the work was to evaluate the productive and reproductive behavior of adult and growing cows of the Nelore race under grazing conditions of the Bolivian tropics. The research work was carried out from October 2016 to October 2017 at rancher farm E7 in Colonia San Juan, Santa Cruz, Bolivia. 100 total cows were used for the study. They were divided into two groups: Adult group: GA, 28 cows ≥ 5 years of life and Growing group: GC, 72 cows ≤ to 5 years of life. The weights between both groups analyzed for GA and GC showed differences between them (p≤0.05) throughout the trial. The body condition between both groups analyzed also showed differences between the groups (p≤0.05). Adult cows had the lowest calving interval (GA: 380 ± 28, GC: 506 ± 18 days, p≤0.003), the best body condition (GA: 2.4 ± 0.06, GC: 2.2 ± 0.02, p≤0.002), the highest live weight (GA: 461 ± 7, GC: 418 ± 5 kg, p≤0,0001) and greater weight of the calf without showing differences p≥0.05 (GA: 34.1 ± 0.8, GC: 32.3 ± 0.5 kg). It is concluded that adult cows have a better productive and reproductive behavior, and it would also be important to maintain a greater percentage of them in the herd for the systems studied. Keywords: adult weight; body condition; calving interval; weight the calf at birth.
Longevity of Nelore Cows of the Bolivian Tropics. Is It Possible to Explain It Through Productive Variables?
(Canadian Center of Science and Education, 2019) Atsuko Ikeda; Ivana Barbona; Yoichiro Hayashi; Juan Antonio Pereira; Pablo Roberto Marini
The objective of this work was to evaluate the longevity and its relationship with productive variables of Nelore cows in grazing systems of the Bolivian tropics. Retrospective data were used corresponding to 259 Nelore breed cows, primiparous and multiparous discarded with a total of 800 births, in the period between 2005 and 2019, belonging to the Cooperativa Agropecuaria Integral San Juan de Yapacan&iacute; (CAISY) located in the San Juan Japanese Communities, Santa Cruz, Bolivia. The variables analyzed were: Live weight of cow (WC) in kg, Weight of the calf at birth (WCB) in kg, Weight of calf at weaning (WCW) in kg, Total weight of weaned calf (WWC) in kg, Age at first calving (AFC) in months, Number of calvings (NC), Longevity (L) in days, Calf Index (CI) in kg, Accumulated Productivity (PAC) in kg, Total calf production (CP) in kg, Efficiency of Stock (ES) in kg. In order to respond to the main objective of this work, the relationship between the life longevity of the cow and the other productive variables was studied. For this, first principal component analysis (PCA) was carried out, by means of which the space dimension of the productive variables was reduced creating new linearly independent variables and in this way avoid problems of multicollinearity in the model, because the productive variables in some cases turned out to be correlated. Then, the first three main components that explain 77% of the total variability of the data were retained and interpreted as follows: The PC1 was high and directly correlated with the variables NC, Kg produced total, % of stock efficiency, PAC and Kg produced meat / day, therefore can be thought of as an indicator of &quot;productive efficiency&quot;. PC2 was an indicator of &quot;efficiency in rebreeding&quot; since it presented altar and direct correlations with WC and AFC. PC3 was high and directly correlated with birth weight and weaning weight, which is interpreted as an indicator of &quot;breeding efficiency&quot;. Finally, a multiple linear regression model was adjusted considering Longevity as a function of productive efficiency, breeding efficiency and rebreeding efficiency (p-value &lt;0.0001 in the three cases). 87% of the total variability of L (days) is explained by the model. It is concluded that Longevity is related to productive indicators for this group of Nelore cows in grazing systems of the Bolivian tropics.
Relationship of Longevity with Productive and Reproductive Variables in Nelore Cows of the Bolivian Tropic
(2020) Atsuko Ikeda; Ivana Barbona; Yoichiro Hayashi; Juan Antonio Pereira; Pablo Roberto Marini
The objective of this study was to evaluate the relationship between longevity with productive and reproductive efficiency variables of Nelore cows in grazing systems in the Bolivian tropics. Retrospective data corresponding to the period 1992-2019, belonging to the Cooperativa Agropecuaria Integral San Juan de Yapacan and the Foundation Technology Center on Agriculture and Livestock, Santa Cruz-Bolivia were used. The data corresponding to 774 Nelore breed cows, primiparous and multiparous discarded with a total of 4050 calvings were evaluated. The following variables were analyzed: Number of calves, live weight of cow in kg, calf weight at birth in kg, calf weight at weaning in kg, total calf weight in kg, age at first calving in months, longevity in days and calving interval in days. Cows born in the year (1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995) are those that arrive later to have their first calving, have a greater calving interval, have greater longevity, similar weaning weight, lower birth weight, lower live weight and higher weight total calf. While cows born in the year (2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) are those that arrive younger to have their first calving, they have a shorter calving interval; have shorter longevity, similar weaning weight, higher birth weight, live weight intermediate and lower total calf weight. For the three periods analyzed, the length of life increases between 0.66-0.95 days on average when the age at first calving increases by one unit, between 1.78-2.99 days on average when the calving-calving interval increases by one unit and between 1.77-1.83 days on average when total calf weight increases by one unit. It is concluded that it was possible to find a model that explained that the greater longevity of Nelore cows in a grazing system in the Bolivian tropics was related to the older age at first calving, the greater calving interval and the greater kg of weights total calves.