When rendering partial view, I lose items loaded with jquery in dropdowlist

I have this main view:

@model JedyHealthWeb.Models.ResponsableCaso

@ {     ViewBag.Title="Responsible for the account.";     Layout="~ / Views / Shared / _LayoutSinControles.cshtml"; }

@section Scripts {     @ Scripts.Render ("~ / bundles / jqueryval")

<script>
    $(function () {
        $("#copiar").click(function () {
            var url = "@Url.Action("ResponsableIgualPaciente", "ResponsableCaso")";
            var valor = @ViewBag.CedulaPaciente;
            loadPartial(url, valor);
        })
    })
</script>
<script>
    $(document).ready(function () {
        var url = "@Url.Action("getSeguros", "ResponsableCaso")";
        var valor = "";
        llenaDropDownSeguros(url, valor)
    })
</script>

}

When you press a button, it updates _CreatePartialResponsable with data, since in the initial load this partial view is empty:

<div class="form-row">
    <div class="form-group col-md-3">
        @Html.LabelFor(model => model.Parentesco, htmlAttributes: new { @class = "titulocampo" })
        @Html.EditorFor(model => model.Parentesco, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.Parentesco, "", new { @class = "text-danger" })
    </div>
    <div class="form-group col-md-9">
        @Html.LabelFor(model => model.DireccionHabitacion, new { @class = "titulocampo" })
        @Html.EditorFor(model => model.DireccionHabitacion, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.DireccionHabitacion, "", new { @class = "text-danger" })
    </div>
</div>

<div class="form-row">
    <div class="form-group col-md-3">
        @Html.LabelFor(model => model.Empresa, htmlAttributes: new { @class = "titulocampo" })
        @Html.EditorFor(model => model.Empresa, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.Empresa, "", new { @class = "text-danger" })
    </div>
    <div class="form-group col-md-9">
        @Html.LabelFor(model => model.DireccionTrabajo, new { @class = "titulocampo" })
        @Html.EditorFor(model => model.DireccionTrabajo, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.DireccionTrabajo, "", new { @class = "text-danger" })
    </div>
</div>

<div class="form-row">
    <div class="form-group col-md-2">
        @Html.LabelFor(model => model.TelefonoTrabajo, new { @class = "titulocampo" })
        @Html.EditorFor(model => model.TelefonoTrabajo, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.TelefonoTrabajo, "", new { @class = "text-danger" })
    </div>
    <div class="form-group col-md-2">
        @Html.LabelFor(model => model.TelefonoHabitacion, new { @class = "titulocampo" })
        @Html.EditorFor(model => model.TelefonoHabitacion, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.TelefonoHabitacion, "", new { @class = "text-danger" })
    </div>
    <div class="form-group col-md-2">
        @Html.LabelFor(model => model.TelefonoCelular, new { @class = "titulocampo" })
        @Html.EditorFor(model => model.TelefonoCelular, new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.TelefonoCelular, "", new { @class = "text-danger" })
    </div>
    <div class="form-group col-md-6">
        @Html.LabelFor(model => model.SeguroNombre, htmlAttributes: new { @class = "titulocampo" })
        <select id="SeguroNombre", name="SeguroNombre" class="form-control"><option value=""></option></select>
        @Html.ValidationMessageFor(model => model.SeguroNombre, "", new { @class = "text-danger" })
    </div>
</div>
<hr />
<div class="form-row">
<div class="btn-group" role="group" aria-label="Control">
    @Html.ActionLink("Regresar", "Index", "Pacientes", null, new { @class = "btn btn-success" })
    <input type="button" id="copiar" value="Copiar de paciente" class="btn btn-success" />
    <input type="submit" value="Continuar" class="btn btn-success" />
</div>

}

After that update is done, the items loaded in the dropdownitem are lost through the document.ready

this is the script that fills the dropdowitem

function llenaDropDownSeguros(url, valor) {

var data = { nombre: valor };
$.post(url, data).done(function (data) {
    if (data.isError) {
        muestraError(data.Titulo, data.Mensaje);
    } else {
        for (var i = 0; i < data.length; i++) {
            $('#SeguroNombre').append('<option value=' + data[i].codigoSeguro + '>' + data[i].descripcion + '</option > ');
        }
    }
});

};

And this is the script I use to update the view with the data

function loadPartial(url, valor) {
$("#esperar").show();
var data = { cedula: valor };
$.post(url, data).done(function (data) {
    if (!data.isError) {
        $("#esperar").hide();
        $("#partialView").html(data);
    } else {
        $("#esperar").hide();
        muestraError(data.Titulo, data.Mensaje);
    }
}).fail(manejarErrorAjax);

};

I have little experience with this javascript and partial views, I think my problem is concept error, but I can not identify, what I'm doing wrong.