Create script and use as input for splunk:

#!/bin/bash

#this script needs the moreutils package

ntpserver="ntp1.domain.tld"
community="<your community string>"
version="2c"

/bin/snmpget -OsQ -v $version -c $community $ntpserver \
	mbgLtNgRefclockStatusA.1 \
	mbgLtNgRefclockStatusB.1 \
	| tr -d " " | ts

Example output:

$ ./get-pzf-stats.sh
Jan 07 23:45:59 mbgLtNgRefclockStatusA.1=96
Jan 07 23:45:59 mbgLtNgRefclockStatusB.1=99