Cattle Reproduction
Turning out a subfertile bull means some cows in the herd won’t get bred or bred in a timely manner. Both problems are costly, says Chance Armstrong, DVM, Auburn University. Check out the two scenarios he outlines here.
Bulls passing all four parts of a BSE are set up for reproductive excellence. The best achieve a 60% to 65% conception rate every 21 days on healthy, cycling cows, says Dr. Chance Armstrong. Subfertile bulls are costly.
The use of A.I. has come a long way since its first use in dairy cattle during the late 1930s. While the technology has vastly changed, the basic principles still remain and practice can help keep skills current.
Statistically, impulse heifer breeding is about 80 percent more variable than planned heifer breeding. Therefore, impulse heifer breeding plays an important role in the dynamics of cattle cycles.
While most cows are in larger groups, bulls tend to be in small groups, resulting in more exposure to the elements. Keeping them protected from the elements is crucial.
Timed A.I. protocols have become so good that farmers, veterinarians and dairy reproductive specialists know they work. The temptation, though, is to tweak those protocols if reproductive performance falls short.
Improved performance is helping dairy producers capitalize on better genetics, according to Dr. Paul Fricke, University of Wisconsin dairy cattle reproduction professor and Extension specialist.
Getting cows pregnant is vital to keeping the pipeline full. According to Jeremey Natzke of Wayside Dairy, a 35% plus pregnancy rate equates to an outstanding repro program and a number his dairy worked hard to achieve.
Rather than focusing breeding goals on being heavily terminal or primarily maternal, sexed semen allows commercial herds of all sizes to “take both roads.”
Crossbreeding has shown increases in growth rate starting in utero, calf survival rate, immune function, average daily gain and longevity in cows.
The industry’s recent push for larger carcass weights while keeping cow costs at a minimum has brought terminal crossbreeding programs to the forefront.