Quite often these days a new genetic index comes along that has been produced for breeders to use in their breeding plan. This month, August 2016, the new index is one that the Council on Dairy Cattle Breeding (CDCB) is calling Cow Livability (C.LIV). For breeders wanting their cows to live for many lactations, this will be a trait of interest.
What is Cow Livability?
CDCB is defining Cow Livability (C.LIV) as a prediction of a cow’s transmitting ability (aka genetic index) to remain alive while in the milking herd.
Every extended day that a cow remains milking in the herd gives the opportunity for more herd profit from more milk revenue and lower replacement costs. Cows that can remain alive when exiting the herd generating breeding stock or beef revenue, instead of the cost associated with deadstock disposal.
Facts About the USA Dairy Herd
It is interesting to note that CDCB reports that USA cow mortality rate averages 7% each lactation and death claims 20% of the USA cows while in the milking herd. On an annual basis that death loss costs the U.S. dairy farms $800 million or approximately $90 per milking cow per year.
How is C.LIV Different than PL?
CDCB provides the following explanation. “In contrast (to C.LIV), PL predicts how long a cow is expected to remain in the milking herd before dying or being culled.”
Livability is one of the traits that make up Productive Life, and it is economically important that cows remain alive, productive and not requiring another cow to replace her.
For decades, cow termination codes have been captured from DHIA herds with 32 million cows in CDCB’s database. Based on that extensive amount of data, CDCB has calculated correlations between C.LIV and PL of 0.70. So they are, in fact, different traits and breeders can expect to see that some sires may be ranked differently for the two traits.
Other Useful Traits
Already available, for a considerable time now, for breeders to use in breeding long-lived trouble free cows have been traits like PL and SCS. But they only partially cover the spectrum of what breeders want to know. For instance, SCS does report the expected SCC level, but it does not cover if in fact a cow is able to resist mastitis. Each mastitis flare up, even though not life threatening, costs $400 (lost revenue, treatment, added labor, lost future production, etc.) To address that, CDN now produces a genetic index for Mastitis Resistance. It includes factors (Read more: MASTITIS RESISTANCE SELECTION: NOW A REALITY!) beyond SCC. Furthermore, Zoetis has now developed a Dairy Wellness Profit Index (DWP$) that is a genetic estimate of a cow’s ability to avoid or resist health problems or disease. (Read More: THE COMPLETE GUIDE TO UNDERSTANDING ZOETIS’ NEW WELLNESS TRAITS – CLARIFIDE® PLUS)
CDN has recently reported a three-year release plan for health and fertility traits. In December 2016 it will publish a metabolic disease (ketosis & displaced abomasum) resistance index, in 2017 an index for resistance to fertility disorders (metritis & retained placenta) and in 2018 a hoof health index.
Considerable research is currently under way, and it will be interesting to see if breeds and/or bloodlines within breeds have different genetic capabilities for these added indexes. Many breeders feel that they detect differences between cow families for these various auxiliary traits.
What Do the Numbers Show for C.LIV?
The following CDCB table shows the importance of having high genetic indexes for individual traits when it comes to a sire having a high NM$ index. All traits are directly or indirectly included the NM$ except for C.LIV. That makes the comparison of C.LIV to NM$ truly independent.
Table 1 Average Genetic Index for USA AI Bulls (born after 1999), Grouped by Percent Rank for NM$
|&RK for NM$||Avg NM$||Milk-lbs||Fat - lbs||Protein-lbs||DPR||PL||C.LIV|
|80 to 99||588||1043||52||38||1.3||5.6||2.1|
|60 to 79||423||944||34||30||0.9||3.8||1.4|
|40 to 59||310||612||25||22||0.4||2.6||0.9|
|20 to 39||197||432||18||16||0||1.4||0.2|
|0 to 19||-53||-164||-2||-2||-0.8||-0.8||-1.1|
Soures: CDCB Article ” Genetic Evaluation for Cow Livability”
It is estimated by D Norman, CDCD and J Wright and P VanRaden, AIPL-USDA that having cows at 2.1 C.LIV compared to -1.1 C.LIV would be worth an additional annual net income of $9,400 (or $38.50 per cow) in the average USA DHIA herd of 244 cows.
CDCB reports that at some time in the future that C.LIV will be included in the four NM$ indexes replacing some of the current emphasis on PL. When that change is made CDCB sees the possibility that the combination of PL (14%) and C.LIV (7%) will move from the current 19% emphasis on PL in NM$ to 21% for PL plus C.LIV
Will These Functionality Traits Be Used?
For breeders that follow the concept of breeding for type and feeding for production, these functional traits are often regarded as a ho-hum issue.
However, for breeders wanting herds of cows that cause few problems, have minimal added expenses, and that remain in the herd a lactation or two longer than cows have in the past, then these additional traits, including C.LIV, will be important, when selecting the sires to buy semen from.
It is highly unlikely that there will be even one sire that is a standout for all functional traits. In fact, that is impossible. However, knowing bull ratings for added functional traits will allow breeds to avoid using sires that are below average for the traits that breeders find relevant to their breeding plan.
The Bullvine Bottom Line
C.LIV is the latest, but certainly not the last, genetic index that will be available for breeders to use to breed functional, commercially profitable cows. Time will tell if it is useful. But the fact remains breeders need to consider all traits for which there are genetic indexes and then make informed choices about which ones to include in their sire selection plan.