A Survey of the Postpartum Reproductive Performance of Dairy Cows with Fertility Problems in Southern Iceland

Abstract

The purpose of this survey was to evaluate the reproductive performance of dairy cows on problem farms in southern Iceland. In all 229 cows on 6 farms were studied. The animals were examined clinically by rectal palpation, once a month. Blood samples were taken 2–5 and 7–10 weeks after calving. The blood samples were analysed for the contents of glucose, urea, inorganic phosphate, calcium and magnesium. Milk samples for progesterone profiles were taken, by the farmer, every 4th day from day 10 postpartum until first oestrus. Because of this sampling method, 128 cows had no rise in progesterone levels, when milk sampling was stopped. These 128 animals were excluded from the study. The results are based on 101 animals.

There was a large variation between cows in postpartum reproductive performance. In the total material 1st ovulation occurred later than reported in many other countries. Fifty percent of the cows had ovulated 35 days after calving and 90 percent 70 days after calving.

The first luteal phase was short in about 60 % of the cows. The progesterone values assayed from those short cycles were lower than the values assayed from the following cycle. First artificial insemination (ai) was on the average 77 days postpartum (pp). The conception rate to first service was 49 %. Of 100 milk samples taken at the time of ai, 20 had high progesterone value. This indicates a high frequency of luteal phase inseminations.

Clinical ketosis was diagnosed in 35 cows. Of these, 31 had a low glucose value. Cows with clinical ketosis ovulated, on the average, later than other animals and 24 ovulated later than 40 days pp. The results indicated that the fertility problems of these cows studied were late ovulations, low conception rate, probably in part, due to luteal phase inseminations, and a high frequency of ketosis which could be caused by low quality feedstuff.

Sammanfattning

Avsikten med undersökningen var att studera orsaken till låg dräktighetsfrekvens och långa kalvningsintervall hos mjölkkor på södra Island.

Totalt ingick 229 kor från 6 gårdar i undersökningen. Korna undersöktes regelbundet, en gång i månaden, kliniskt genom rektalpalpation.

Blodprov samlades i intervallen 2–5 och 7–10 veckor efter kalvning. Blodproverna analyserades för glukos, urea, fosfat, kalcium och magnesium.

Mjölkprover för analys av progesteron togs var 4:e dag från dag 10 till första brunst. Denna provtagningsmetod orsakade att endast progesteronprofiler från 101 kor kunde räknas. Övriga 128 kor hade inte förhöjda progesteronvärden när provtagningen avbröts.

Resultaten från 101 kor visar på en avsevärd variation mellan djur beträffande könsfunktionerna efter kalvning. I hela materialet inträffade den första ovulationen efter kalvning senare än vad som rapporteras från många andra länder. Femtio kor hade ovulerat inom 35 dagar efter kalvning och 90 kor hade ovulerat 70 dagar efter kalvning. Den förstå lutealfasen postpartum var kort och progesteronnivåerna i mjölken var låga i 60 % av korna.

Förstå ai var mellan 35–145 dagar efter kalvning. Konceptions-frekvensen var 49 %. Etthundra mjölkprov tagna samtidigt med insemination analyserades med avseende på progesteron. Tjugo av dessa pröver hade höga progesteronvärden och ingen av dessa inseminationer resulterade i dräktighet.

Trettiofem kor diagnosticerades med klinisk ketos. Trettioen av dessa kor hade låga glukosvärden i blodet. Merparten av ketoskorna ovulerade senare än kor som in te hade klinisk ketos.

Dessa resultat tyder på att kornas fertilitetsproblem kan bero på der as almänna skötsel och utfodring.