NLMIXED in R

Plotting NLMIXED Model

#### Plotting NLMIXED Model #####
try.nlm2<-nlme(y~U+D*exp(-(Kd*x)),
               data=Grass_compl,
               fixed=U+D+Kd~1, 
               random=U+D+Kd~1|Trial/Cow,
               start=c(U=20,D=50.88,Kd=0.02698),
               method="ML", 
               control=nlmeControl(maxIter=1000, msMaxIter = 100))
               
pdata<-expand.grid(x=as.numeric(0:350),
                   Trial=unique(Grass_compl$Trial),
                   Cow=unique(Grass_compl$Cow))
pdata2<-as.data.frame(predict(try.nlm2, newdata=pdata, level=0:2)) # predict for all three levels --> predict.fixed, predict.trial, predict.Cow
head(predict(try.nlm2, newdata=pdata, level=0:2))
pdata<-cbind(pdata,pdata2[,2:5])
rm(pdata2)
pdata<-pdata[,c(1:2,4:7)]

myx<-scale_x_continuous(breaks=c(0,8,16,32,56,96,336))
myy<-scale_y_continuous(breaks = seq(0, 80, by = 10))
ggplot(Grass_compl, aes(x=x,y=y))+
  myx+
  myy+
  labs(title = "DM residue over time in 8 Trials / 39 Cows", y="DM residue", x="Time (hours)")+
  geom_point(colour="grey80")+
  theme_bw()+
  geom_line(data=pdata, aes(y=predict.Cow, group=Cow, colour="Cow"),lwd=1, alpha=0.5)+
  geom_line(data=pdata, aes(y=predict.Trial, group=Trial, colour="Trial"),lwd=2, alpha=0.7)+
  geom_line(data=pdata, aes(y=predict.fixed, colour="Population"),lwd=2.5, alpha=1)+
  scale_colour_manual(name="Line Color",
                      values=c(Cow="blue", Trial="green", Population="red"))

myx<-scale_x_continuous(breaks=c(0,8,16,32,56,96,336))
myy<-scale_y_continuous(breaks = seq(0, 80, by = 10))
ggplot(Grass_compl, aes(x=x,y=y, colour=Trial))+
  myx+
  myy+
  labs(title = "DM residue over time in 8 Trials / 39 Cows", y="DM residue", x="Time (hours)")+
  geom_point(colour="grey80")+
  theme_bw()+
  geom_line(data=pdata, aes(y=predict.Cow, group=Cow),lwd=0.7, alpha=0.3)+
  geom_line(data=pdata, aes(y=predict.Trial, group=Trial),lwd=1.5, alpha=1)+
  geom_line(data=pdata, aes(y=predict.fixed), colour="black",lwd=2, alpha=1)