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The aim of the study was to examine the ratio of different calving courses of Angus, Charolaise, Hereford, Limousin and Simmental beef breed cows in relation to the age at first calving as well as frequency of assisted calvings depending on the cow's age at first delivery. 6549 calvings were analyzed. The percentage of difficult deliveries, regardless of age at first calving, was low and amounted to 5.6%. A highly significant dependence between first calving age and its course was noticed. The most assisted deliveries were observed in the group of cows delivering the first calf up to 25 months of age. The cow's breed statistically had a highly significant influence on calving course: The lowest ratio of assisted deliveries was noticed for Simmental and Angus cows, the most for Charolaise and Limousin cows. In case of Angus, Hereford and Limousine breeds there was no statistically significant relationship between age at first calving and its course. Taking into consideration the influence of age of first calving on its course, it should be stated that there are not any contraindications for primiparous cows of Angus, Hereford and Limousine breeds to deliver for the first time at 2 years of age.
Medycyna Weterynaryjna
|
2010
|
tom 66
|
nr 08
s.566-569,rys.,tab.,bibliogr.
The aim of this study was to determine the effect of the origin of service sires on calving ease in dairy cattle herds. The experiment involved a total of 1257 Polish Holstein-Friesian Black-and-White cows. Variability of traits associated with calving ease was estimated on the basis of direct observation. Calving heifers and cows after the second and third pregnancy lasting at least 260 days were taken into consideration. Twin pregnancies were not taken into account, because by nature they are associated with a high proportion of difficult calvings. The experimental factors were as follows: calving ease (1 - birth independently without human assistance; 2 - birth requiring a little help from one person; 3 - severe birth, requiring the use of much strength and the help of several people; 4 - very heavy labor needing the assistance of a veterinarian, including a caesarean section), the age of the cows (1 - first calving, 2 - second calving, 3 - third calving), the country of origin of 100 sires (France, USA, Poland, Germany) and calf birth weight. Overall, 15.67% of the calvings were considered hard pulls and required the assistance of a veterinarian (10.26% and 5.41% respectively). The number of difficult births decreased in successive calvings. Calving difficulty increased with calf birth weight. Calving ease was significantly affected by the sire. The highest percentage of hard pull and veterinary-assisted calvings (24.79%) was noted in the group of calves sired by a German bull, while the greatest calving ease was reported for American service sires. The high variation in the results of a phenotypic evaluation of bulls with respect to calving ease indicates that this trait should be considered in dairy herd improvement programs, and suggests that the country of origin of sires is less important than their actual test scores.
The purpose of the study was to evaluate the performance of Scottish Highland cattle in Polish production systems. Research material consisted of the cattle’s performance records provided by the Polish Association of Beef Cattle Breeders and Producers. The data comprised the following traits: cow weight, height at withers and at sacrum, chest circumference, calf weight at calving and at 210th day, calving difficulties, calves stillborn and growth gains. In this study 495 calvings were examined. All calvings were described as “easy, natural, without the need for human assistance.” Similarly good results were observed with regard to calves stillborn: only 4 calves were lost. The studies revealed that the average weight of Highland calves at birth in 2007-2011 remained at a similar level (24 kg for heifers and 25 for bulls), but a decrease in growth gains of calves at the age of 210 days was noted (by over 200 g/day). This phenomenon may have been related to a decreased milk productivity of cows and to genetic factors.
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