Why I added New Zealand genetics to my mini Jersey herd

After raising miniature Jerseys for a few years I became interested in raising our miniature Jerseys on pasture. I gradually reduced the concentrates that I fed the cows during milking and began to learn and practice rotational grazing and then intensive rotational grazing.

I found that the miniature Jerseys I had then, including Gingersnap and Molly, did quite well on the pasture-based system. Both Snap and Molly are capacious or stout which, as I later learned, is important for grazing efficiency. Also they bred soon after calving even when nursing a calf which translates to high fertility and is one of the most important traits in any dairy cow system but especially important for a grazing dairy cow. Snap and Molly were also easy to handle, move to new pastures, contain in single-stranded fencing. 

A daughter of Hillstar Terrific 5 Star

Could I improve production and udder conformation without increasing size (too much) or risk losing condition on pasture?

When selecting a herdsire it is important to consider the traits you would like to add or improve in the herd. For Molly and Snap I could use some improvement in udder conformation. Their udders and teats were OK just not as tight or in the shape of registry cows. One of 5-Star’s daughters is pictured above.

Their milk production was moderate and I wondered if that could be improved without compromising the grazing traits I was enjoying. I knew from another higher production cow that there was the risk of losing condition if the cow’s production and condition depended on concentrates. 

Hardly any Miniature Jersey bull or sire information 

At the time (about 2010-2011) there were two miniature Jersey breed registries but these registries offered little information about the few sires that were available through AI or about other miniature Jersey bulls. Information on farmer websites about mini Jersey bulls was sparse.

In contrast the American Jersey Association directory and other international Jersey directories provided an overwhelming amount of statistics about  their sires.

Advice

I talked with my AI technician who, as a dairy farmer, raised and bred registered standard Jerseys and was very familiar with American Jerseys. Because of my interest in grazing, he recommended a New Zealand Jersey sire rather than an American Jersey sire.

I discussed the situation with Maureen Neidhardt, the director of the AMJA, American Miniature Jersey Association, the registry for Dolly, Gingersnap and Molly. Maureen encouraged me to breed my miniature Jerseys with New Zealand Jersey semen. 

New Zealand Sire Directory

There are a few New Zealand directories. I chose the LIC NZ directory which has regional USA representatives.

The traits listed in the data about the New Zealand sires included “Conformation” traits of Stature and Capacity. I looked particularly for a sire with significantly negative Stature and positive Capacity (short and stout). I could also select for positives in udder support and overall udder conformation (as well as a host of other traits).

I selected Hawthorne Grove Zeus and asked my semen sales representative for another sire based on my criteria. He suggested Donald’s Edify.  The next year I selected Hillstar Terrific 5-Star.

Risks and Downsides

One of the main risks of my plan was larger offspring. New Zealand Jerseys are generally smaller than American Jerseys and I had selected for some of the shortest available but there was no actual height data. Also if the calves were larger then there was the risk of delivery complications.

The other downside was that all the New Zealand sires at the time, similarly to registered American Jersey sires, were horned. I had had polled calves for several years so I had to relearn how to deal with horned calves.

Results So Far - Height

I am pleased with the results of adding New Zealand genetics to my miniature Jersey grazing herd so far. 

Early on I had some added height but no delivery issues. Lately my cows have continued to decrease in size as noted below.

My AI tech successfully AI’d my miniature Jersey cows five times with New Zealand semen and I got three bulls (Leo from Zeus, Rupert from Edify and Goldstar from 5 Star) and two heifers (Merry and May from Zeus).

From this first generationTwo bulls, Leo and Goldstar, and one of the heifers, Merry, were mid-sized with a mature height of about 46”.  

Rupert’s mature height was under 42” and May’s mature height was 39.5".

For the next generation I began to use my own bulls and with 1/4th New Zealand and 3/4 miniature Jersey the cows and bulls were quite short, all under 40” and some exceedingly short like Merry’s Ruby at 36” at two years.  

Subsequent generations have gradually become shorter with occasional cows over 40” but now with cows averaging about 38” and bulls averaging about 40”.