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Relative reticulo-rumen pH indicators for subacute ruminal acidosis detection in dairy cows
- C. Villot, B. Meunier, J. Bodin, C. Martin, M. Silberberg
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Subacute ruminal acidosis (SARA) is usually characterized by abnormal and intermittent drops in rumen pH. Nevertheless, high individual animal variability in rumen pH and the difference in measurement methods for pH data acquisition decrease the sensitivity and accuracy of pH indicators for detecting SARA in ruminants. The aim of this study was to refine rumen pH indicators in long-term SARA based on individual dairy cow reticulo-rumen pH kinetics. Animal performances and rumen parameters were studied weekly in order to validate SARA syndrome and rumen pH was continuously measured using reticulo-rumen sensors. In total, 11 primiparous dairy cows were consecutively fed two different diets for 12 successive weeks: a control diet as low-starch diet (LSD; 13% starch for 4 weeks in period 1), an acidotic diet as high-starch diet (HSD; 32% starch for 4 weeks in period 2), and again the LSD diet (3 weeks in period 3). There was a 1-week dietary transition between LSD and HSD. Commonly used absolute SARA pH indicators such as daily average, area under the curve (AUC) and time spent below pH<5.8 and pH<6 were processed from absolute (raw) daily kinetics. Then signal processing was applied to raw pH values in order to calculate relative pH indicators by filtering and normalizing data to remove inter-individual variability, sensor drift and sensor noise. Normalized AUC, times spent below NpH<−0.3 and NpH<−0.5, NpH range and NpH standard deviation were calculated. Those relative pH indicators were compared with commonly used pH indicators to assess their ability to detect SARA. This syndrome induced by HSD was confirmed by consistent expected changes in milk quality, dry matter intake and acetate : propionate ratio in the rumen, whereas the ruminal concentration of lipopolysaccharide was increased. Commonly used pH SARA indicators were not able to discriminate SARA syndrome due to high animal variability and sensor drift and noise, whereas relative pH indicators developed in this study appeared more relevant for SARA detection as assessed by receiver operating characteristic tests. This work shows that absolute pH kinetics should be corrected for drift, noise and animal variability to produce relative pH indicators that are more robust for SARA detection. These relative pH indicators could be more relevant for identifying affected animals in a herd and also for comparing SARA risk among studies.
High concentrate-induced subacute ruminal acidosis (SARA) increases plasma acute phase proteins (APPs) and cortisol in goats
- Y. Y. Jia, S. Q. Wang, Y. D. Ni, Y. S. Zhang, S. Zhuang, X. Z. Shen
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The aim of this study was to investigate changes of stress status in dairy goats induced to subacute ruminal acidosis (SARA). The level of acute phase proteins (APPs) including haptoglobin (HP) and serum amyloid A (SAA) in plasma and their mRNA expression in liver, as well as plasma cortisol and genes expression of key factors controlling cortisol synthesis in adrenal cortex were compared between SARA and control goats. SARA was induced by feeding high concentrate diet (60% concentrate of dry matter) for 3 weeks (SARA, n=6), while control goats (Con, n=6) received a low concentrate diet (40% concentrate of dry matter) during the experimental time. SARA goats showed ruminal pH below 5.8 for more than 3 h per day, which was significantly lower than control goats (pH>6.0). SARA goats demonstrated a significant increase of hepatic HP and SAA mRNA expression (P<0.05), and the level of HP but not SAA in plasma was markedly increased compared with control (P<0.05). The level of cortisol in plasma showed a trend to increase in SARA goats (0.05<P<0.1). In adrenal cortex, mRNA expression of 17α-hydroxylase cytochrome (P45017α) (P<0.01) and 3β-hydroxysteroid dehydrogenase (3β-HSD) (P<0.05) was significantly increased in SARA goats. The contents of 3β-HSD and P450 side-chain cleavage protein were increased by 58.6% and 39.4%, respectively, but did not reach the statistical significance (P>0.05). These results suggested that SARA goats experienced a certain stress status, exhibiting an increase in HP production and cortisol secretion.
A constant goal, changing tactics: The Krusenbaum dairy farm (1996–2005)
- Joshua L. Posner, Gary G. Frank, Kenneth V. Nordlund, Ronald T. Schuler
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- Renewable Agriculture and Food Systems / Volume 24 / Issue 1 / March 2009
- Published online by Cambridge University Press:
- 09 December 2008, pp. 8-18
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This case study documents the trajectory of a successful alternative dairy farm in southeastern Wisconsin. The 1990s were a difficult period for dairying and the Krusenbaum family entered this shifting field in 1990 with a 37-cow Holstein herd in a stanchion barn, 88 tillable hectares and a vision to gradually develop a biodynamic dairy. Low milk prices and the unrelenting workload associated with conventional dairying forced the family to look for alternative strategies. By 1995 they had converted all their land to 47 rotationally grazed paddocks, increased herd size to 70 cows and their annual net farm income had grown to a solid $54,000. The workload remained very heavy, and during the next few years they introduced a swing-16 milking parlor that approximately doubled their milking efficiency and allowed them to again increase herd size, implemented seasonal dairying and constructed an outwintering shed (1997) that greatly facilitated animal management during the winter. By 2002 the farming system had been, by and large, consolidated and by not focusing solely on milk production and crossbreeding with non-Holstein breeds, the herd benefited from improved reproductive vigor. They were then able to synchronize annual calving and the herd's maximum nutritional needs with the spring flush of their pastures, which resulted in lowered purchased feed costs per cow. By this time, annual milk production was fairly constant [around 7400 kg rolling herd average (RHA)], herd health was good and annual net farm income had grown to $75,600. In 2003, the farm became certified organic. With this change the value of the milk increased dramatically from $0.31 liter−1 to $0.45 liter−1 ($14.27–$20.24 per hundredweight), but feed costs climbed sharply due to the high cost of organic feed, as did labor costs due to the decision to train new farmers in grass-based dairying rather than simply hire employees. Due to very sound farm management, good money management and an entrepreneurial philosophy, this farm, by most performance standards, is now both highly profitable and environmentally sound and the families living on it have a good quality of life.