Housing tiestall dairy cows in deep-bedded pens during an 8-week dry period: Effects on lying time, lying postures, and rising and lying-down behaviors.

Dairy cow lying behavior is useful in determining the cow's level of welfare, as well as in determining how her environment may affect her comfort and ease of movement. In tiestall systems, cows usually remain in a stall for the duration of their lactation. The dry period offers a unique opportunity to provide alternative housing to the cow with minimal effects on farm housing and management. Our objective was to determine whether housing tiestall cows in deep-bedded pens over an 8-wk dry period altered lying time, lying and rising ability, or lying postures. At dry-off, 20 cows, paired by parity and calving date, were randomly assigned to a deep-bedded loose pen (LP) or a tiestall (TS). Leg-mounted pedometers measured lying time. Rising and lying ability were measured using 6 events of rising and lying from 24-h video recordings taken once a week per cow. Sequenced images (1/min) from the 24-h recordings were used to document lying postures and locations for each cow. Data were analyzed for the early (first week of dry-off), mid, and late (week before calving) terms of the dry period. Lying time did not differ between LP and TS but was numerically higher for LP than TS cows (14.4 vs. 13.0 h/d, respectively). Contact with stall or pen confines when lying down was 5 times higher in TS than LP. The increased contact, coupled with a higher occurrence of hindquarter shifting in the late term, led to higher overall abnormal lying behaviors in TS. Contact with the stall upon rising increased in the late term for TS cows. Cows housed in loose pens also exhibited greater variation in hind-leg postures, keeping legs tucked 20% less often in favor of alternative postures. Stall hardware (e.g., tie rail, dividers) may have affected the ease of transition between lying and standing, leading to higher levels of contact with the stall. Loose-pen cows are able to assume more postures than TS cows when provided more space, possibly allowing them to orient themselves in ways that provide greater comfort. Lying surface in the deep-bedded loose pen may ease the cow's lying-down and rising movements and lead to the higher lying time found with LP cows. Overall, aspects of the stall largely contributed to differences in lying behaviors, warranting further study into whether freestall systems would yield similar outcomes. Improving our concept of ease of movement related to lying and quality of rest in dairy cows, through evaluating lying behaviors in different housing systems, allows for better recommendations on viable alternative housing options.

The treatment of cheese whey wastewater by sequential anaerobic and aerobic steps in a single digester at pilot scale.

The treatment of reconstituted whey wastewater was performed in a 400 L digester at 20 degrees C, with an anaerobic digestion step, followed by a step of aerobic treatment at low oxygen concentration in the same digester. In a first set of 48 cycles, total cycle time (T(C)) of 2, 3 and 4 days were tested at varying organic loading rates (OLR). The COD removal reached 89+/-4, 97+/-3 and 98+/-2% at T(C) of 2, 3 and 4 days and OLR of 0.56, 1.04 and 0.78 g COD L(-1) d(-1), respectively. The activity of the biomass decreased for the methanogenic population, while increasing by 400% for the acidogens, demonstrating a displacement in the predominant trophic group in the biomass bed. A second set of 16 cycles was performed with higher soluble oxygen concentration in the bulk liquid (0.5 mg L(-1)) during the aerobic treatment at a T(C) of 2 days and an OLR of 1.55 g COD L(-1) d(-1), with a soluble COD removal of 88+/-3%. The biomass specific activities showed a compartmentalization of the trophic group with methanogenic activity maintained in the biomass bed and a high acidogenic activity in the suspended flocs.

Coupled anaerobic-aerobic treatment of whey wastewater in a sequencing batch reactor: proof of concept.

A proof of concept was performed in order to verify if the coupling of anaerobic and aerobic conditions inside the same digester could efficiently treat a reconstituted whey wastewater at 21 degrees C. The sequencing batch reactor (SBR) cycles combined initial anaerobic phase and final aerobic phase with reduced aeration. A series of 24 h cycles in 0.5 L digesters, with four different levels of oxygenation (none, 54, 108 and 182 mgO2 per gram of chemical oxygen demand (COD)), showed residual soluble chemical oxygen demand (sCOD) of 683 +/- 46, 720 +/- 33, 581 +/- 45, 1239 +/- 15 mg L(-1), respectively. Acetate and hydrogen specific activities were maintained for the anaerobic digester, but decreased by 10-25% for the acetate and by 20-50% for the hydrogen, in the coupled digesters. The experiment was repeated using 48 h cycles with limited aeration during 6 or 16 hours at 54 and 108 mgO2gCODinitial(-1), displaying residual sCOD of 177 +/- 43, 137 +/- 38, 104 +/- 22 and 112 +/- 9 mgL(-1) for the anaerobic and the coupled digesters, respectively. The coupled digesters recovered after a pH shock with residual sCOD as low as 132 mg L(-1) compared to 636 mg L(-1) for the anaerobic digester. With regard to the obtained results, the feasibility of the anaerobic-aerobic coupling in SBR digesters for the treatment of whey wastewater was demonstrated.