Evaluation of different acute-phase proteins for herd health diagnostics in early postpartum Holstein Friesian dairy cows.

This research communication describes (1) the comparison of acute-phase protein (APP) concentrations in transition dairy cows on different farms using both pooled and individual blood samples, and (2) the association among different APP and clinical health parameters. The first hypothesis was that early postpartum dairy cows from different farms differ in the level of inflammation, which might be determined using APP assays in both pooled and individual blood samples. The second hypothesis was that the APP haptoglobin (Hp) might be the most sensitive parameter to detect cows at risk of excessive postpartum inflammation concomitant with systemic disease. Serum concentrations of Hp, serum amyloid-A (SAA), total protein (TP), albumin (Alb), coeruloplasmin (Cp) and C-reactive protein (CRP) in 100 fresh lactating cows (within 0-8 d postpartum) from 10 farms were compared and associated to clinical health parameters (rectal body temperature, vaginal discharge (Metricheck™ score), rumen fill, vulvovaginal laceration) using both pooled and individual blood samples. Mean serum concentrations of Hp, SAA and TP revealed significant differences among farms. Pooled serum samples of farms showed high correlations with the mean of individual samples. Only Hp was significantly positively correlated to both body temperature and Metricheck™ score. In conclusion, Hp differentiates dairy farms regarding the inflammatory state of transition cows using individual and pooled serum samples within the first week postpartum. It also mirrors the individual degree of inflammation, thus proving to be a diagnostic parameter of high interest during the periparturient period.

Application of strong ion difference theory to urine and the relationship between urine pH and net acid excretion in cattle.

OBJECTIVE: To develop an equation expressing urine pH in terms of independent variables, derive an equation relating urine pH to net acid excretion (NAE), and apply this new knowledge to determine the role that monitoring urine pH should play when diets with low cationanion difference are fed to dairy cattle. ANIMALS: 11 Holstein-Friesian cows. PROCEDURES: A physicochemical strong ion approach was used to develop a general electroneutrality equation for urine that involved urine pH and strong ion difference (SID [difference between strong cation and strong anion concentrations]), PCO(2), the concentration of ammonium ([NH(4)(+)]) and phosphate ([PO(4)]), and 3 constants. The general electroneutrality equation was simplified for use in bovine urine and applied to 321 data points from 11 cows fed different diets. RESULTS: Urine pH was dependent on 4 independent variables (urine SID, [NH(4)(+)], PCO(2), and [PO(4)]) and 3 constants. The simplified electroneutrality equation for bovine urine was pH approximately {pK(1)' - log(10)(S PCO(2))} + log(10)([K(+)] + [Na(+)] + [Mg(2+)] + [Ca(2+)] + [NH(4)(+)] - [Cl(-)] - [SO(4)(2-)]). The relationship between urine pH and NAE (in mEq/L) for cattle fed different diets was pH = 6.12 + log(10)(-NAE + [NH(4)(+)] + 2.6). CONCLUSIONS AND CLINICAL RELEVANCE: A change in urine SID, [NH(4)(+)], PCO(2), or [PO(4)] independently and directly led to a change in urine pH. Urinary [K(+)] had the greatest effect on urine pH in cattle, with high urine [K(+)] resulting in alkaline urine and low urine [K(+)] resulting in acidic urine. Urine pH provided an accurate assessment of NAE in cattle when pH was > 6.3.

Duration of the effects of anionic salts on the acid-base status in cows fed different anionic salts only once daily.

Seeing the fact that farm managers in Germany feed anionic salts to transition cows once daily, this study set out to evaluate whether the effects on the acid-base status (ABS) and calcium excretion in urine would persist throughout the entire day beyond this feeding practice. Eleven non-lactating, non-pregnant, Holstein-Friesian-cows with a rumen fistula were administered 2Eq of calcium chloride (CaCl(2)/five cows) or calcium sulfate (CaSO(4)/six cows) once daily for a period of 1 week. At day 7, blood and urine samples were taken every 4h starting at 06:00 a.m. before feeding the anionic salts, and then ending at the same time the next day. Feeding anionic salts to the cows induced metabolic acidosis in both of the groups. The changes tended to be greater in CaCl(2)-cows. After 12h, the acidosis lessened and the initial values were reached after 24h. The CaCl(2)-cows, however, still showed signs of compensated metabolic acidosis. The results of the present study showed that feeding anionic salts once daily confined the risk of an interrupted effect of the anionic salts on the acid-base status as well as calcium metabolism after 12h.

The role of dietary calcium concentration in the use of anionic salts to prevent parturient paresis in dairy cows.

The role of dietary calcium concentration during the feeding of anionic salts (AS) was reviewed. Hypocalcaemia is still the major cause of parturient paresis in dairy cows. Feeding AS is an established method for preventing severe hypocalcaemia by activating the calcium metabolism in the last two to three weeks before parturition by inducing a metabolic acidosis. In compensation for this acidosis, the organism increases the concentrations of ionised Ca [Ca2+] in the blood. This increase leads to an increasing excretion of calcium via the urine, which is ensued by an increased calcium absorption in the intestine. The ongoing metabolic acidosis changed the flux of Ca. The size of the Ca pool, however, remained unchanged. As the calcium metabolism is activated by AS, it seems necessary to increase the amount of calcium that is fed to the cows. Several studies examined the impact of different dietary calcium concentrations on the acid-base balance and the calcium metabolism in cows fed anionic salts. The study designs vary concerning the amounts of calcium fed and the use of pregnant or non-pregnant cows. Only one study combined the feeding of AS with a very low amount of calcium, which fell below the daily requirements of pregnant cows in the last three weeks before parturition. In this study, the calcium balance post partum was better in the cows that were administered AS and a high calcium diet. In the other studies, the amount of calcium in the different experimental groups and the difference between the amounts of calcium fed varied greatly. As far as it was monitored in the studies, the calcium concentration of the diet did not have a significant impact on the degree of acidosis induced by AS. In pregnant cows, no significant differences in the calcium concentration in serum or urine occurred before parturition. Some of the researchers found a lower incidence of parturient paresis when cows were fed a combination of AS and a higher amount of calcium, but some other researches did not. Interestingly, the parameters of bone metabolism did not change between experimental groups. According to what is currently known, the feeding of AS to transition cows should not be combined with a dietary calcium concentration that falls below the requirement of cows in this stage of lactation. On the other hand, there is no need to increase the Ca concentration. When AS are used the dietary calcium concentration should be between 9 g and 12 g/kg dry matter. Further research is needed to investigate the role of dietary calcium regarding the use of AS for improving Ca metabolism in dairy cows around parturition.

The impact of dietary cation anion difference (DCAD) on the acid-base balance and calcium metabolism of non-lactating, non-pregnant dairy cows fed equal amounts of different anionic salts.

We evaluated the impact of the dietary cation-anion difference (DCAD) on the influence of anionic salts (AS) on the metabolism of dairy cows using a study-design that included control of feed intake. Ten mature, non-lactating, non-pregnant, Holstein-Friesian-crossbreed cows received 2000 mEq of either one of the seven anionic salts tested, two combinations of the anionic salts or water as control via a rumen cannula. Salts and controls were assigned in a 10x10 Latin square design. Whole blood, serum and urine samples were taken during treatment (TP) and washout period. Samples of whole blood were tested for pH, base-excess and bicarbonate concentrations. In urine, pH and net acid-base excretion (NABE) were analysed. Calcium was measured in serum and urine. According to the different batches of hay, five groups of DCAD were created regarding cluster analysis. Changes in urine and blood parameters were statistically analysed for each DCAD group separately. The different DCAD had an impact on the amount of change in acid-base balance (ABB) and calcium metabolism and for how long these changes lasted. In the DCAD group receiving the highest amount of AS (239 mEq/kg dry matter with AS), changes of ABB were only noticeable in urine and these changes only differed from day zero in the first week of TP (P<0.05). In the other four groups changes of ABB were also visible in blood parameters, but only on a few days of TP did the deviations differ significantly (P<0.05) from day zero. Changes of ABB parameters in urine samples were more pronounced than those in blood and differed clearly from day zero (P<0.05). Parallel to the changes of ABB, calcium concentrations in these samples were significantly increased (P<0.001) in all DCAD groups. Except for the highest DCAD group, ionized calcium concentrations changed over time (P<0.020). However, the differences were very small and only differed from day zero on a few TP days. We conclude that the DCAD of a dairy cow's diet has an important impact on the effect of AS on ABB and calcium metabolism with respect to the duration and amount of change. The target regions of DCAD should be clearly below 100 mEq/kg dry matter to ensure the desired effect on ABB and calcium metabolism. Extremely negative DCAD should be avoided to minimize the risk of clinical acidosis induced by AS.

[Impact of a simultaneous application of anionic salts and rumen buffer on acid-base-balance and mineral metabolism in dairy cows]. / Auswirkungen einer gleichzeitigen Gabe von sauren Salzen und Pansenpuffern auf den Säuren-Basen-Haushalt und Mineralstoffwechsel von Milchkühen.

In this study, the influence of simultaneous application of anionic salts (AS) and rumen buffer (RB) on the metabolism of dairy cows was examined. Eleven rumen fistulated, non-pregnant and non-lactating dairy cows received equal amounts of one AS (CaCl2 or CaSO4) and one RB (NaHCO3 or KHCO3) via rumen cannula during feeding time over a period of eight days. Before the first application of AS and RB and on day eight of the treatment period, blood, urine and rumen fluid samples were taken. The following parameters were measured: whole blood: pH, base excess, bicarbonate; serum: sodium, potassium, chloride, calcium; urine: pH, net acid base excretion, sodium, potassium, chloride, calcium; rumen fluid: pH. The changes of each parameter were compared via ANOVA. The changes in acid-base balance on day eight were very small, although significant. But p-values showed that the statistical evidence was low. The most changes occurred when NaHCO3 was fed in combination with one of the AS used. In this case a small acidogenic load was seen in blood (p < 0.05), and calcium concentrations increased slightly (p < 0.05). No alkalotic reaction could be detected when any combination of AS and RB were given to the cows. Simultaneous application of AS and RB results in a loss of effectivity of AS. Neither an adequate acidification of blood nor an activation of calcium metabolism occurred. In feed ration for cows in the last weeks of pregnancy, rumen buffer must not be fed, if anionic salts are given for prevention of parturient paresis.