Reproduction management in a dairy herd
10:30 (GMT+2), Mon , 12 May 2014
Fertility in dairy cows is defined by three indicators, i.e. (1) the ability of cows to show heat soon after calving, and (2) to become pregnant with a minimum number of inseminations and (3) to remain pregnant until the next calving. These basic indicators could be expanded to include more information, such as the interval from calving to conception and artificial insemination success rate.

The herd consisted of 160 cows of which 138 (or 86%) were in milk. This is a first indication of reproduction problems as cows are usually being milked longer when reproductive problems occur causing an increase in the percentage of cow in milk. This is further confirmed by the high average number of days-in-milk(DIM) of 176 days which should be closer to 150 DIM. This will also result in a reduction in the average daily milk yield of the herd because more cows are in late lactation.

All dry cows are pregnant while 37 and 56 % of cowsmore than 100 and 200 DIM respectively are pregnant. These figures are low which should be higher than 60 and 85% respectively. This follows that 44% of cows more than 200 DIM have not been confirmed pregnant. Insemination records indicate that most of these cows have recently been inseminated.

The average interval from calving to first artificial insemination (AI) is 65 days which is very good with 79% of first AI’s done within 80 days after calving. First insemination success rate is however only 28%. This should be more than 60% to reduce the interval from calving to conception or days open (Dopen) which is high at 147 days resulting in a high calving interval of about 425 days. A further problem is the high number of all AI’s per conception whichis estimated by the sum of all inseminations divided by the number of confirmed pregnancies. The inverse of the number of AI’s per conception gives an indication of the efficiency of insemination for confirmed pregnancies which is for this herd low at 41%.

In this herd first insemination is done early although at a low first insemination success rate. This could indicate cows not fully recovered after calving.The interval from calving to conception is long requiring a high number of inseminations per conception. To improve herd reproduction management attention should be given to heat detection and insemination techniques including semen quality.

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