The autumn low milk yield syndrome in Brown Swiss cows in continental climates: hypotheses and facts

Extensive research has been conducted globally on the impact of heat stress (HS) on animal health and milk production in dairy cows. In this article, we examine the possible reasons for the decrease in milk production in Brown Swiss (BS) cows during the autumn season, known as the autumn low milk yield syndrome (ALMYS). This condition has been extensively studied in high-yielding Holstein Friesian (HF) cattle and has also been observed in BS cows with a daily milk yield of around 30 kg. Our hypothesis is that the drop in milk yield and the increased prevalence of mastitis in autumn, as found in our recent studies, may be a long-term consequence of summer HS. We re-evaluate our previous findings in light of the possible manifestation of an HS-related form of ALMYS in BS cows. As milk yield, mastitis spread, and reproductive function of cows are interrelated and have seasonal dependence, we examine the consistency of our hypothesis with existing data. The significant drop in milk yield in BS cows in autumn (by 2.0-3.2 kg), as well as the threshold of milk yield decrease (temperature-humidity index of 70.7), may point in favour of the manifestation of ALMYS in BS cows, similar to HF cows. Only the percentage effect of seasonal factor (59.4%; p < 0.05) on milk yield of BS cows was significant. HS-related ALMYS provides a robust conceptual framework for diverse sets of productive and animal health data in BS cows, similar to observations in high-yielding HF cattle. However, the limitations associated with the lack of additional data (e.g. immunological indicators) suggest the need for further research to confirm ALMYS in BS breed.

Influence of country of origin and lineage on the lifetime milk production of Holstein cows

<b>This work investigated the percentage influence of country of origin and lineage on parameters of lifetime milk production in Holstein cows brought as heifers to Ukraine from Western Europe. The animals were kept untethered in new, modern, uninsulated steel cowsheds in a large dairy complex. Data from the Orsek dairy management system were used to evaluate randomly selected cows of different origins with complete lactation for lifetime milk, fat and protein yield. Despite significant differences in milk productivity between animals depending on their country of origin and line, the share of the influence of these factors was fairly small. Two-way analysis of variance showed that the percentage influence of the line on lifetime milk yield was 5,5%, and its influence on the yield of milk fat and protein was 6,3-7,8%. The percentage influence of the country of origin was even smaller, at 0,5–2,6% (with a greater impact on milk yield). The rather small effect of the factors studied could be due to the influence of environmental factors (feeding and living conditions), which should be investigated in further studies. </b>