Lameness in sows has an economic impact on pig production and is a major welfare concern. The aim of the present project was to develop methods to evaluate and quantify lameness in breeding sows. Five methods to study lameness were compared between themselves and with visual gait scoring used as a reference: footprint analysis, kinematics, accelerometers, lying-tostanding transition and foot lesion observation. Fifty sows of various parities and stages of gestation were selected using visual gait scoring and distributed into three groups: lame (L), mildly lame (ML) and non-lame (NL). They were then tested using each method. Kinematics showed that L sows had a lower walking speed than NL sows (L: 0.83 6 0.04, NL: 0.96 6 0.03 m/s; P , 0.05), a shorter stride length than ML sows (L: 93.0 6 2.6, ML: 101.2 6 1.5 cm; P , 0.05) and a longer stance time than ML and NL sows (L: 0.83 6 0.03, ML: 0.70 6 0.03, NL: 0.69 6 0.02 s; P , 0.01). Accelerometer measurements revealed that L sows spent less time standing over a 24-h period (L: 6.3 6 1.3, ML: 13.7 6 2.4, NL: 14.5 6 2.4%; P , 0.01), lay down earlier after feeding (L: 33.4 6 4.6, ML: 41.7 6 3.1, NL: 48.6 6 2.9 min; P , 0.05) and tended to step more often during the hour following feeding (L: 10.1 6 2.0, ML: 6.1 6 0.5, NL: 5.4 6 0.4 step/min standing; P 5 0.06) than NL sows, with the ML sows having intermediate values. Visual observation of back posture showed that 64% of L sows had an arched back, compared with only 14% in NL sows (P 5 0.02). Finally, footprint analysis and observation of lying-to-standing transition and foot lesions were not successful in detecting significant differences between L, ML and NL sows. In conclusion, several quantitative variables obtained from kinematics and accelerometers proved to be successful in identifying reliable indicators of lameness in sows. Further work is needed to relate these indicators with causes of lameness and to develop methods that can be implemented on the farm.

The objective was to assess persistence with antihypertensive therapy (AHT) and discontinuation patterns in patients newly dispensed different antihypertensive drug classes in a natural Canadian population-based setting. Hypertensive patients initiating AHT monotherapy were included in this 3-year retrospective cohort study (N ¼ 21 326) using the Saskatchewan health-care databases. Persistence was defined as consistently refilling a new prescription for AHT within 90 days of a previous dispensing. New courses of AHT were also documented in nonpersistent patients. Kaplan-Meier and Cox regression analyses were used to compare persistence and new courses of therapy across initial drugs. Compared to the newer angiotensin II antagonists (AIIAs), the likelihood of discontinuing therapy over the 39-month study period was significantly higher for angiotensin-converting enzymes inhibitors (HR ¼ 1.29; 95% CI ¼ 1.16-1.43), calcium channel blockers (HR ¼ 1.42; 95% CI ¼ 1.27-1.60), beta blockers (HR ¼ 1.62; 95% CI ¼ 1.45-1.80) and diuretics (HR ¼ 1.92; 95% CI ¼ 1.73-2.14). In the year following treatment discontinuation, between 54 and 75% of patients initiated a second course of treatment. Patients initiated on an AIIA had a significantly higher likelihood of starting a new course of therapy after a first treatment discontinuation, compared to all other agents. In conclusion, hypertensive patients initiated on an AIIA not only had greater persistence to AHT but were also more likely to initiate a new course of AHT after discontinuation than those initiating treatment with other agents. Further studies are required that relate intermittent treatment behaviours to health outcomes and costs in hypertension.

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