Page 8 - Hooked on Herefords Oct 2021

Technical Update Posy Moody | NZH Manager

Days to Calving

What is the ‘Days to Calving’ EBV? While many producers manage the reproductive
Days to Calving are estimates of genetic differences performance of their female herd using different
between animals in the time from the start of the joining strategies, in particular the culling of females that fail
period (ie. when the female is introduced to a bull) until to get in calf, research has shown that female fertility is
subsequent calving. influenced by the genetics of the breeding herd.

How are Days to Calving EBVS communicated? How do you submit Days to Calving information?
Days to Calving EBVs are expressed in ‘days’ and are There are two different methods available to submit
calculated from the natural joining details of both heifers the joining details and fate/disposal information to PBB
and mature cows. registry for days to calving. NOTE disposals recorded on
Most variation in this trait occurs in how long it takes the ADLS are not included in the Days to Calving analysis,
the females to get pregnant (eg did she get pregnant in so you need to submit disposals separately by using either
the first cycle, second cycle or not at all) with only a small of the two options below
amount of variation in this trait due to gestation length.
Lower more negative days to calving EBVs are more 1. Herds that us software packages (eg HerdMASTER,
desirable as they indicate females that conceive earlier in Stockbook) can extract the joining details from
the joining period. their computer program and submit the details to
registry electronically. If you require assistance
Why is the Days to Calving Information Important?
either entering the details contact PBB.
Reproductive performance is a key factor of profitability OR
in a beef farming. Consequently, selection for improved
reproductive performance should be an important 2. Microsoft Excel template is available. The template
consideration for all beef cattle producers. One major can be accessed from the NZ Hereford website or by
component influencing a beef performance is the fertility contacting Samantha (samantha@pbbnz.com )
of the female herd. As you know the job of a female in a
beef producing herd is to conceive, (preferably as early Days to Calving EBVs provide a useful tool that breeders
in the joining period as possible), carry a foetus during can use to improve the genetics of their females for
gestation, deliver a live calf and raise it until weaning, fertility, in association with their routine management and
within every 12-month period of her breeding life. A culling strategies.
female that does not do this is failing to do her job and
11/06/21
eroding herd profitability. 2021 HEREFORD GROUP BREEDPLAN
Genetic Trends for Birth and Fertility Traits for the Breed
10 10
Gestation Length
Calv.Ease Direct 2021 HEREFORD GROUP BREEDPLAN
Calv.Ease Dghtrs
8 Birth Wt. 8
Scrotal Size Genetic Trends for Birth and Fertility Traits for the Breed
Days to Calving
6 6
(EBV) 4 4

Value 2 2
Breeding 0 0

Estimated -2 -2

-4
-4
-6 -6

-8 -8

-10 -10
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
Calving Year
8 | NZ Herefords Newsletter. October, 2021 Hooked on Herefords