Many dairy cows experience a high incidence of health problems during the transition period (TP). The TP is an intermediate stage of various digestive, metabolic and reproductive functions which determine the general health status at the time of calving and during the first weeks postpartum. Negative energy balance due to increased energy demand at parturition and significantly reduced dry matter intake relative to demand is an important determinant. Consequently, substantial lipid mobilization from adipose tissue, increased oxidative stress and impaired immunity are associated with higher incidences of periparturient health problems including ketosis or subclinical ketosis (SCK), which have tremendous economic impact on dairy productivity. SCK is defined as the presence of increased blood ketone bodies (BHBA: betahydroxybutyric acid, acetone, acetoacetic acid) without clinical ketosis signs. Varying blood and milk cut-off values have been reported for BHBA concentrations defining SCK, but the most commonly accepted values are ≥ 1.2 mmol/L and ≥ 200 μmol/L respectively. This underestimated disease can impact dairy cow productivity through decreased milk production in the order of roughly 300 kg/lactation and increases the risk of metabolic and reproductive diseases such as displaced abomasum, retained placenta, metritis, mastitis, prolong oestrus interval and reduces conception rates. SCK also referred to as ‘profit robber or killer’ can cause productivity and economic losses of between $200-290 per dairy cow annually. Options for the control and prevention of SCK include controlled-release monensin capsules, and the injectable combination butaphosphan and cyanocobalamin and oral propylene glycol. SCK is easy to detect in early lactation using cow-side validated BHBA analysers with high specificity and sensitivity.

Phosphorus is critical for life and an indispensable element for biologically occurring organic molecules such as DNA, ATP, and phosphoproteomes. Butafosfan is a synthetically produced organic phosphorous (phosphonic acid) compound that contains 17.3% phosphorus. It does not belong to the group of biologically occurring organic phosphorous compounds. Butafosfan has been used in many animal species as a metabolic stimulant interfering with energy metabolism. Vitamin B12 (VB12) is a unique cobalt-containing vitamin. It functions as a cofactor for the enzymes methionine synthase and methyl-malonyl-CoA mutase. It is necessary for the conversion of propionate into succinyl-CoA in ruminants. A combination of butafosfan and VB12 (iBC) has been available for veterinary use since 1958 and the first publication appeared in the 1970s in cows. However, the first molecular biological studies about its mode of action appeared in early 2000s. Recent studies revealed that iBC has significant effects on carbohydrate and lipid metabolism. Investigations between 1970 and 1994 focused mainly on cows at risk of metabolic and reproductive disease in the dry period. Studies as of 2000 investigated its efficacy for the prevention and treatment of subclinical and secondary ketosis, adjunctive/supportive therapy for displaced abomasum operation, milk fever, improvement of postoperative rumen activity, uterus involution, and mastitis in transition dairy cows.

The present study analyzed the transformation of dairy cattle population and changes in yearly milk production and per lactation milk yield (1991 -2019) in Turkey. In addition, metabolic and reproductive diseases frequently seen in high milk yielding dairy cows (HYDC) and problems causing low milk yield were investigated. The number of dairy cows, culled and sent to slaughter was investigated for the last three years in Turkey. On the other side, the cost of the most common metabolic diseases by region has been analyzed by a phone survey (40 vets were asked in different regions). The dairy cow population was 6118997 in 1991 (HYDC pure breed: 10.6% and traditional indigenous dairy breed: 55.3%). The dairy cow population reached 6580753 in 2019 (7.5 % increase compared to 1991) which consisted of pure breed HYDC of 49.4% and traditional dairy breed of 8.9%. This is a transformation in dairy cattle population in 28 years. Yearly total milk production increased by 141.2% from 8.616.412 tons (1991) to 20782374 tons (2019). Yearly milk production per lactation/cow increased from 1.4 tons (1991), to 1.65 tons (2000) and to 3.16 tons (2019) which means 17.5% and 124.3% increase, respectively. The growth of the number of HYDC pure breed and their total yearly milk production was 399.3% (650739 -3249002) and 555.6% (1913438 tons to 12544507 tons) in 28 years, respectively. Numerous metabolic and reproductive diseases can often be observed in HYDCs due to genetic reasons as well as nutritional and maintenance mistakes during the transition and dry period which can cause economic loss related to milk yield and metabolic diseases. The treatment cost of the metabolic or reproductive diseases for the farmers was between 150-1200 TL per case. Many of the animals were sent to compulsory slaughter and culled because of these diseases. Indeed, a total of 738681 dairy cows have been sent to slaughter throughout the last three years.

A total of 300 dairy cows were randomly enrolled from 11 dairy farms in Turkey. The beta-hydroxybutyric acid concentration (BAC) was tested in the blood (BBAC) and individual milk (MBAC) samples at postpartum week 2 (PPW2) and week 4 (PPW4) for the detection of subclinical ketosis (SCK) in Holstein, Montbeliard, Simmental and Holstein-Crossbred (HC; only BBAC). The prevalence of BSCK (BBAC ≥ 1.2 mmol/L), MSCK1 (MBAC = 100 µmol/L), MSCK2 (MBAC ≥ 200 µmol/L) and MSCK1/2 (≥ 100 µmol/L) was 8.3, 11.8, 5.8 and 17.3% at PPW2 and 4.7, 4.9, 6.9 and 11.9% at PPW4 in Holstein respectively. SCK was not observed in Simmental and HC. The prevalence of BSCK and MSCK1 at PPW2 were 4.3 and 43.5% in Montbeliard respectively. Primiparous Montbeliard and Holstein had significantly higher MBAC at PPW2 than PPW4. Overall, HC and Montbeliard had significantly lower BBAC. Cows having body condition scores 2 and 4 at calving had higher MBAC at PPW2 and 4 that was associated significantly with metritis and multiple diseases. Holstein with BCS4 at calving had higher BBAC at PPW2 and 4. Holstein with SCK was more likely to develop postpartum metabolic health disorders (PPHD) in 90 days in milk (90DIM). MSCK1 did not associate milk production loss in Montbeliard and Holstein. Holstein with both BSCK and MSCK2 at PPW2 had a 6.7 kg average daily milk yield loss in 90DIM. Conclusively, SCK was not observed in Simmental and HC, and MSCK1 didn’t cause PPHD and milk yield loss in Montbeliard. BSCK and MSCK2 created a significant risk for PPHD and milk production loss in Holstein.

Background: Accurate analysis of ionized calcium (iCa) is critical for the detection of hypocalcemia or subclinical hypocalcemia. The Edan i15 Vet (EDAN) blood gas device has not been validated for iCa in dairy cows. Objectives:We aimed to validate the EDAN blood gas device against the Gem Premier 3000 (GEM) analyzer by measuring iCa concentrations and evaluating the ability of these measurements, compared with serum total calcium (TCa) concentrations, to diagnose subclinical hypocalcemia.Methods: iCa concentrations were measured with the EDAN and GEM devices, and serum TCa concentrations were measured with a wet biochemistry method with blood from 125 lactating Holstein cows between calving to day 27 postpartum.Results: Bland-Altman plots showed a mean and total bias of 0.05 and 0.24 mmol/L for the EDAN device, respectively. The intercept did not include zero, but the slope included 1.0 in the Passing-Bablok regression. The sensitivity and specificity (Se/Sp) of the EDAN device were 93/94%, 93/90%, 91/93%, and 85/95% for iCa cut-off values of <1.00, 1.05, 1.10, and 1.15 mmol/L, respectively, as determined with the GEM device. The Se/Sp were 57/82% and 72/80% for EDAN and 57/80% and 72/79% for GEM at serum TCa cut-off points <2.15 and <2.00 mmol/L, respectively. The average iCa concentrations analyzed with the GEM and EDAN devices were 1.04 ± 0.18 and 1.09 ± 0.17, respectively. Conclusions:The EDAN device did not have satisfactory agreement with GEM and could not be used interchangeably, but it had satisfactory Se/Sp to diagnose subclinical hypocalcemia compared with the GEM-derived iCa cut-off points. Serum TCa concentration cut-off values were not suitable for diagnosing subclinical hypocalcemia because of unsatisfactory Se/Sp compared with iCa concentrations analyzed by the GEM and EDAN devices. The iCa values analyzed using the EDAN and GEM devices were consistent with previously reported data.

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Lactating Holstein (n=125) were enrolled randomly for the coccygeal whole blood analysis by blood gas devices GEM Premier 3000 (GEM) and Edan i15 Vet (EDAN) between calving to postpartum day 3 (G1) and postpartum day 4 to 27 (G2). Blood pH, ionised calcium (ICA7.4) and lactate analysis were significantly correlated between GEM and EDAN (r=0.86, 0.94, 0.87 respectively). The bias for ICA7.4, lactate and pH analysis was -0.054, -0.344 mmol/L and +0.009 respectively. ICA7.4 was correlated negatively with parity and chloride, but positively with lactate. The averages of ICA7.4 and serum total calcium (TC) was significantly lower in G1 than G2. Chloride and lactate were significantly higher in G1 than G2. Subclinical hypocalcemia prevalence (SCH) (serum TC<2.15 mmol/L, as reference) was 52.9% in G1 and 21.1% in G2. Cows with SCH had frequently over 50% ICA7.4/TC ratio. Sensitivity analysis provided a sensitivity of 57.4% for ICA7.4 cut-points of 1.02 (GEM) and 1.05 (EDAN) mmol/L to detect SCH based on reference serum TC. Primiparous (PRP) with and without SCH in G1 had significantly higher ICA7.4 than multiparous (MUL). Cows with SCH had significantly higher chloride in G1 than G2. MUL had significantly higher lactate and chloride in G1 than G2. Conclusively, ICA7.4 and pH analysis between GEM and EDAN were correlated well with acceptable biases, but high differences occurred in lactate analysis. MUL was at risk in G1 due to lower ICA7.4 and TC over PRP. Higher ICA7.4 of PRP can reduce the risk and frequency of clinical hypocalcemia. SCH correlated negatively with Cl concentration in G1, but not lactate.