## 3 Results
However, compiling the results of the whole herd never fully reflects the real situation in the herd--as shown by the results in Figures 1-4, this herd indeed had ketosis. Figure 1 shows the results of the C18:1 trans11 content in cows' milk per 100 g of fat, which depends on the age of the cows and the blood BHBA content. The TVA content remained at a similar level throughout the experiment in healthy primiparous (PH) and multiparous (MH) cows, while the results were quite different in animals diagnosed with ketosis (MK, PK). During the first week of lactation, PH and MH milk had by far the highest TVA content, while the lowest content was found in multiparous cows with ketosis (MK). Compared to animals whose blood results indicated ketosis, TVA content was 0.212 g higher in primiparous females and 0.161 g higher in multiparous females. In the second week, there was a decrease in TVA content in PH, MH, and MK cows, while the primiparous animals with ketosis (PK) experienced a 0.15-gram increase in TVA content. In the third week of lactation, the highest TVA content was found in milk from MK cows, where the highest increase in TVA content was also observed, amounting to 0.493 g; the lowest value was observed in PK cows. Figure 2 shows the C18:2 n-6 content depending on the age of the cows and the BHBA content in blood. The results showed quite large fluctuations in this fatty acid's content across the different groups of animals participating in the experiment. LA content in the milk of primiparous cows showed a similar trend of decreasing content over the course of the experiment; in addition, the LA content, for both healthy and diseased primiparous cows, was higher in the first week of lactation than that in multiparous cows. LA content in multiparous cows was quite variable. In MH cows, the LA content increased in the second week of lactation and decreased in the third week; however, in MK cows, the lowest LA level of all animal groups was observed for the first two weeks of the experiment. In addition, a decrease in LA content was observed in the second week compared to the first week of lactation, while in the third week, there was a significant increase in LA content in the milk of these cows, which totaled 0.905 g/100 g fat--this figure was the highest value recorded among the experimental groups. Figure 3 shows the results of C18:2 cis9,trans11 content according to the age of cows and the BHBA content in blood. In the first week of lactation (days 5-7), the highest CLA9 content was observed in PH and MH milk, with the lowest content found in PK and MK milk. In particular, the CLA9 content in MH milk was high, amounting to as much as 0.833 g/100 g of fat, while in PH milk, the respective figure was 0.684 g/100 g of fat. The CLA9 content in the milk of PH cows in the first week of lactation was 32.75% higher than that in PK milk, while in MH milk, the respective figure was 67.7% higher than that in MK milk. In the second week of lactation (days 8-14), the highest CLA9 content was found in PH milk, despite experiencing a decrease compared to the first week, and in PK milk, the CLA9 content of which had increased. On the other hand, there was a rather large \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**Treatment Effect**} \\ \cline{2-5}  & **1** & **2** & **3** \\ \hline  & LSM & 0.93 AB & 0.67 A & 0.68 B \\ BHBA & SEM & 0.072 & 0.066 & 0.057 \\ \hline \hline \end{tabular} BHBA—\(\theta\)-hydroxobutyric acid.  
\end{table} 
Table 3: BHBA content in blood depending on the week of lactation [mmol/L]. Data were presented as least-squares means with the standard error of the mean. Treatment effect: 1 st week of lactation; 2 nd week of lactation; 3 rd week of lactation. Means marked with the same letters differ significantly at lowercase letters, \(p\leq 0.05\); uppercase letters, \(p\leq 0.01\). reduction in the CLA9 content in MH milk, which experienced a fall of up to 55%.