Reproductive state of dairy cow sector in the Principality of Asturias (Spain)

The dairy sector has been involved in an intensification process for the last decades. Under the hypothesis that the milk yield is related to the level of intensification of herds, the current reproductive status and reproductive technologies used in the Principality of Asturias were evaluated in relation to the size of the dairy farms. This was carried out through a survey to 2.4% of total active dairy cows stakeholders in the region to obtain reproductive data and the use of reproductive technologies. The yield per lactation and cow was lower in the farms with less production level (6,656 L) than in the rest of the farms (8,640, 9,322 and 10,070 L/cow in farms with production levels between 175-325 tonnes milk/year, 325-500 tonnes milk/year and >500 tonnes milk/year, respectively; P<0.001). However, the number of lactations per cow decreased when the production level increased from <175 to >500 tonnes milk/ year (6.1 to 3.0 lac-tations per cow, P<0.001). A number of 2.61 inseminations were necessary to obtain a delivery irrespective of the production level, with an interval between calving and next fertilization of 131 days in the most productive farms and 99 in the less productive ones (P<0.05). Hormonal treatments, sexed semen and embryo transfer were used to a greater extent as the size of the herd increased. No differences were observed in the incidence of reproductive pathologies among production levels. The results show that the production level of the farms affects the productive and reproductive performances of the animals.