Body condition scores, parity, blood and milk beta-hydroxybutyric acid concentrations
The averages of BCS, BBAC and MBAC in the study cows were presented in Table 1. All primiparous and multiparous cows have lost significantly BCS at PP30 and PP60 compared to calving (p < 0.01), except for primiparous Simmental. There was a significant difference between breeds. BCS1 was not observed at calving in breeds. BCS2, BCS3 and BCS4 were detected in Holstein by 47%, 41%, and 8.6% at calving respectively. The average parity of Holstein, Montbeliard, Simmental and HC was 2.93 ± 0.11 (n = 37 primiparous, n = 179 multiparous), 3.09 ± 0.31 (n = 5 primiparous, n = 18 multiparous), 2.26 ± 1.03 (n = 9 primiparous, n = 29 multiparous), 2.04 ± 1.15 (n = 11 primiparous, n = 12 multiparous) respectively. The average parity of Simmental and HC were significantly lower (p < 0.01) than Montbeliard and Holstein. Figures 1 and 2 present BBAC and MBAC for different BCSs at calving. The average BBAC of Holstein at PPW2 or 4 was significantly (p < 0.05) higher if they got BCS4 at calving. Holstein cows having BCS4 or BCS2 at calving had significantly higher MBAC at PPW2 compared to BCS3 groups (p < 0.01). The significantly high MBAC at PPW4 was observed in Holstein cows having BCS2 at calving. Holstein having significantly high BBAC at PPW2 had BCS4 at PP30 and PP60. Significantly high BBAC at PPW2 was observed in Simmental cows having BCS4 at PP30 (p < 0.01). Correlation coefficients between BBAC and MBAC were r = 0.60 and r = 0.86 (p < 0.05) at PPW2 and PPW4, it was r = 0.36 and r = 0.14 (p > 0.05) in Holstein and Montbeliard cows respectively. Correlation coefficients for BBAC and MBAC were r = 0.45 and r = 0.75 (p < 0.05) between PPW2 and PPW4 in Holstein respectively. No significant correlation was found in other breeds.
Prevalence of subclinical ketosis detected in the blood (BSCK) and milk (MSCK)
BSCK was not detected in Simmental (farm 9, 11) and Holstein-Crossbred (farm 10) neither at PPW2 nor PPW4. BSCK was detected in Holstein farms (farms 2, 3, 5, 6, 7 and 8) at a rate of 8.3 and 4.7% at PPW2 and 4 respectively. The difference between PPW2 and PPW4 was significant (p < 0.01). Holstein farms 1 and 4 were negative for BSCK. Out of 23 Montbeliard cows, 1 primiparous cow with BCS4 at calving showed BSCK at PPW2 (4.3%) only, but that cow became negative at PPW4. The descriptive data about the prevalence of BSCK, the parity and BCSs were presented in Tables 2 and 3 for Holstein cows. Primiparous Holstein that was tested positive for BSCK at PPW2 and 4, lost significantly (p < 0.05) BCS at PP60. The correlation coefficient was r = 0.34 (p > 0.05) for BSCK between PPW2 and PPW4 in Holstein. No significant correlation was found in other breeds. The prevalence of MSCK in Holstein cows was presented in Table 2. The highest prevalence was observed in the MSCK1/2 group in Holstein, which was 17.3 and 11.9% at PPW2 and 4 respectively. The difference between PPW2 and 4 was significant (p < 0.01). MSCK1 and MSCK2 prevalence were 4.9, 5.8% and 5.8, 6.9% at PPW2 and 4 in Holstein respectively. The difference between PPW2 and PPW4 was significant (p < 0.01) in MSCK2. MSCK2 prevalence was negative in Holstein farms 1, 3 and 4. There were more MSCK2 positive multiparous Holstein at PPW4 compared to primiparous. No significant difference was found in BCSs of MSCK2 positive multiparous Holstein cows between calving, PP30 and PP60. However, all primiparous cows tested positive for MSCK lost BCS between calving, PP30 and PP60. Correlation coefficients were r = 0.26 and r = 0.48 (p > 0.05) for MSCK1 and MSCK2 between PPW2 and PPW4 in Holstein respectively. It was not applicable in other breeds. MSCK1 incidence in Montbeliard was 43.5% at PPW2, but all cows became negative at PPW4. MSCK1 or 2 in Simmental cows (farm 9 and 11) and MSCK2 in Montbeliard were negative. The combined prevalence of BSCK/MSCK1 and BSCK/MSCK2 was 4.0 and 2.0% at PPW4 in Holstein cows respectively. The prevalence of BSCK/MSCK1/2 was 8.6 and 4.0% at PPW2 and PPW4 in Holstein respectively. The difference between PPW2 and 4 was significant (p < 0.01). No combined prevalence was observed in Montbeliard and Simmental cows. It was not applicable for Holstein-Crossbred. The percentage of BSCK, MSCK1 and MSCK2 positive cases at both PPW2 and PPW4 were 2.3, 5.9 and 3.0% in Holstein respectively. No correlation between PPW2 and 4 was existed (p > 0.05).
Culling and postpartum health disorders
The culling rate was 3.7% among Holstein cows in 90DIM. None of culled Holstein cows had BSCK at PPW2 or 4. Holstein cows that were positive for MSCK1, MSCK1/2 and MSCK2 at PPW2 created a likelihood of 6.3, 12.5 and 25% for culling risk respectively. MSCK2 positive cows were significantly more likely (OR:11.20, p < 0.05) to be culled than even MSCK1/2 (OR:3.46). MSCK1 did not create a significant risk for culling. The average BCS of culled Holstein was normal (BCS3) at calving, but a significantly BCS loss was observed at PP30 (BCS1). The difference between BCSs of culled Holstein (2.48 ± 0.20) and non-culled Holstein (2.95 ± 0.03) was significant at PP30 (p = 0.026). The average parity of culled Holstein was 3.62 (one primiparous, 7 multiparous). Mastitis (n = 1), metritis (n = 1) and displaced abomasum (n = 1), MD (n = 1, 12%), lameness (n = 2, 25%) were observed in culled Holstein. No associations were observed in other breeds between culling and SCK. The incidence of PPHD and its association with SCK in Holstein was presented in Table 3. Simmental and HC were not positive for SCK and no severe PPHD was observed in Montbeliard cows that were positive for BSK and MSCK1 at PPW2. MSCK1 did not correlate with PPHD in Holstein. CK, DA, metritis, mastitis, lameness and multiple diseases were observed moderately and, in some cases, significantly higher in Holstein cows that were positive for BSCK, MSCK1/2 and MSCK2 at PPW2 or 4 (Table 3). BSCK and MSCK2 positive Holstein at PPW2 or 4 were more likely to developing CK (OR: 15.4, p < 0.05). These cows had significantly higher average BCS at PP30 and moderately lower average parity compared to cows not having CK. DA was detected in 10% of Holstein cows that were positive for BSCK at PPW4, however, this did not create a highly significant risk (p = 0.09) (Table 3). Metritis was one of the most frequently observed PPHD in study cows (Montbeliard n = 1, Holstein n = 15). Holstein that was positive for SCK had frequently metritis cases, however, the incidence (25%) was most remarkable in MSCK1/2 positive Holstein at PPW4 (p = 0.06, OR: 4.48). Average BBAC at PPW2 and MBAC at PPW4 were significantly (p < 0.05 and < 0.01) higher in cows having metritis (Fig. 3). Those cows had also a moderate significantly (p = 0.07) lower BCS (2.81) at PP60 than other cows. Out of 300 study cows, 42 Holstein (14%), 2 Montbeliard (0.6%) and 1 Simmental cow had mastitis in 90DIM. Cows with mastitis had significantly (p < 0.05) lower average BCS at calving (3.23) and higher average parity (3.38 ± 0.27). There was a significant difference (p = 0.015) between BCS2 (having 24% of mastitis) and other BCS groups concerning the existence of mastitis. However, Holstein cows that were positive for MSCK1/2 at PPW4, were more likely to have mastitis (33.3%, p < 0.05, OR: 5.08) (Table 3). Ten percent of all study cows had lameness in 90DIM. The majority of them were multiparous (average parity was 3.29 ± 0.31, p = 0.06). The BBAC of cows with lameness was moderately high but not significant (p = 0.09) at PPW4 compared to cows without lameness. Holstein cows had frequently lameness in all SCK groups, especially cows having BSCK at PPW4 had a moderate significantly higher incidence of lameness (30%, p = 0.06, OR: 4.25). The incidence of CO was 3% among all study cows (Holstein n = 8, and Simmental n = 1), no significant relation was found between BBAC and MBAC. Sixteen among all study cows (Montbeliard n = 1, Holstein n = 15) had multiple diseases. They have got constantly higher BBAC and MBAC at PPW2 and 4, thus MBAC at PPW4 was significantly higher (p < 0.05) in cows having multiple diseases (Fig. 3). These cows had also significantly lower BCS at PP60 (2.73 ± 0.08) compared to cows without multiple diseases (2.97 ± 0.03). Holstein cows with positive BSCK, MSCK1/2 and MSCK2 had multiple diseases at certain rates. But, Holstein having had positive MSCK1/2 at PPW4 showed an incidence of 25% multiple diseases (OR: 4.5, p = 0.06) (Table 3).
Association of BSCK and MSCK with the average daily milk yield
The ADMY was compared between SCK positive and negative cows in 90DIM and presented in Tables 4, 5 and 6, Figs. 4 and 5 in Holstein cows only. Simmental cows (all were SCK negative) was disregarded in the milk yield analysis concerning SCK to prevent the dilution of the data. ADMY of all Simmental was 26.80 ± 0.80 kg in 90DIM. The average monthly milk yield of Simmental cows were 26.27 ± 0.87, 27.10 ± 0.66, 27.36 ± 0.85 kg in the first, second and third month after calving respectively (data was not shown in tables). There was no significant effect (p > 0.05) of high MSCK1 prevalence in Montbeliard at PPW2 on ADMY (positive: 38.45 ± 2.17 kg; negative: 35.47 ± 2.14 kg) in 90DIM. Montbeliard had in an average of 31.91 ± 1.45, 37.17 ± 1.91 and 40.45 ± 1.65 kg milk yield in the first, second and third month after calving respectively, and the first-month milk yield was significantly different (p = 0.00) (data was not shown in tables). Holstein had a significantly lower average monthly milk yield in the first month compared to the second and third months after calving, however, there was a difference between SCK positive and negative cows (Table 4). Average daily, weekly and monthly milk production of BSCK and MSCK2 negative Holstein had always an upwards trend throughout 12 weeks postpartum in comparison to positive cows (Table 4, 5, 6 and Figs. 4 and 5). The difference in ADMY between SCK negative and positive cows was significant at weeks 10th, 11th and 12th (Figs. 4 and 5). ADMY of Holstein cows having negative BSCK at PPW2 and PPW4 looked higher than cows having positive BSCK, however, the difference was not statistically significant. However, MSCK2 positive Holstein cows at PPW2 had moderate significantly (p = 0.07) lower ADMY (Table 4). ADMY was significantly different in Holstein that was in combined prevalence groups of BSCK and MSCK2, and roughly 5.4 kg and 4 kg higher ADMY was observed in SCK negative cows than positive cows respectively (Table 5). If Holstein cows were positive both for BSCK and MSCK2 at PPW2, ADMY was 6.7 kg less than negative cows, which was significant (p ≤ 0.05) (Table 5). MSCK1 and MSCK1/2 in Holstein did not have a significant effect on average daily, weekly and monthly milk yield in 90 DIM, even no effect was observed in the combined prevalence groups. Therefore the data was not presented in the tables. ADMY of PRP Holstein that was negative for BSCK (40.59 ± 1.45 kg) at PPW2 was significantly higher (p ≤ 0.05) than those with positive BSCK (33.55 ± 2.79 kg) in 90 DIM, which meant an average 7 kg milk yield loos per day (Table 4). Besides, PRP Holstein was negative for BSCK at PPW2, had a much higher milk yield in the second and third months postpartum (Table 6). The average monthly milk yield of all Holstein and PRP Holstein, that were negative for BSCK or MSCK2 at PPW2, was markedly higher at second and third month postpartum, thus the difference was significant (p < 0.05) at 2nd month after calving, and moderately significant (p = 0.07) at third month after calving (Table 6).