J. Connor

Role of transportation in spread of porcine epidemic diarrhea virus infection, United States.

After porcine epidemic diarrhea virus (PEDV) was detected in the United States in 2013, we tested environmental samples from trailers in which pigs had been transported. PEDV was found in 5.2% of trailers not contaminated at arrival, , suggesting that the transport process is a source of transmission if adequate hygiene measures are not implemented.

Effect of day of mixing gestating sows on measures of reproductive performance and animal welfare.

Effects of day of mixing sows after breeding were measured for reproduction and welfare on a commercial research farm. Sows (n = 1,436) were weaned into stalls for breeding, and groups of sows were assigned to 1) no mixing and housed in individual stalls (STL), 2) mixed on d 3 to 7 after breeding (D3), 3) mixed on d 13 to 17 after breeding (D14), or 4) mixed 35 d after breeding (D35). Mixed sows were moved into pens (n = 58 sows/pen) with an electronic sow feeding station and maintained as a static group. In the first 12 d after mixing or movement into STL (period 1), sows were assessed for lameness and lesions every 3 d and then every 2 wk until farrowing (period 2). Cortisol and fights were measured in period 1. Conception rates were reduced (P < 0.005) in D3 (87.1%) and D14 (89.2%) compared to D35 (92.2%) and STL (96.2%). Farrowing rates were lower (P < 0.0001) in D3 (82.8%) compared to D35 (90.5%) and STL (96.2%), but litter size was not (P ≥ 0.20) affected by mixing. The proportion of sows bred within 10 d of weaning was reduced (P < 0.05) for D14 compared to STL, but D3 and D35 did not differ among treatments. Number of fights 24 h after mixing was less (P < 0.0001) for D14 compared to D3 and D35 groups, and serum cortisol was greater (P < 0.05) for D35 compared to STL and D3. From period 1 to 2, lameness increased in D3 and decreased in D35 but did not change for D14 and STL (treatment × period, P < 0.05), whereas leg inflammation did not differ (P > 0.10) among treatments. Head and body lesion scores declined from period 1 to 2 in all mix groups, whereas vulva lesions increased in the D3 and D35 but did not change in D14 and STL (treatment × period, P < 0.0001). These results suggest STL can improve most measures of welfare compared to mixing in groups. However, when mixing sows, assessments for reproductive performance and welfare may change from gestation to farrowing. The poorest reproductive performance and welfare was observed when sows were mixed 3 to 7 d after breeding. There were few differences between the D14 and D35 treatments in reproduction or welfare, but D14--not D35--differed from STL in weaned sows rebred. Overall, results of this trial suggest that, even though any of the mixing days can result in acceptable measures of reproduction, there are clear effects of day of mixing on fertility and welfare, and special attention should be focused on the long-term reproductive and welfare consequences.

Effect of timing of relocation of replacement gilts from group pens to individual stalls before breeding on fertility and well-being1

Variation in gilt fertility is associated with increased replacement and reduced longevity. Stress before breeding is hypothesized to be involved in reduced fertility. This study tested the timing of gilt relocation from pens to individual stalls before breeding on fertility and well-being. The experiment was performed in replicates on a commercial research farm. After detection of first estrus, gilts ( = 563) were assigned to treatment for relocation into stalls 3 wk (REL3wk), 2 wk (REL2wk), or 1 wk (REL1wk) before breeding at second estrus. Subsets of gilts from each treatment ( = 60) were selected for assessment of follicles at second estrus. Data included interestrus interval, number of services, conception, farrowing, total born, and wean to service interval. Piglet birth weight was obtained on subsets of litters ( = 42/treatment). Measures of well-being included BW, backfat, BCS, lesions, and lameness from wk 1 after first estrus until wk 16. Gilt BW at wk 5 (158.4 kg) was not affected ( > 0.10) by treatment. Measures of BCS, lameness, and lesions at breeding and throughout gestation did not differ ( > 0.10). Treatment did not affect ( > 0.10) gilts expressing a normal interestrus interval of 18 to 24 d (83.4%) but did influence ( < 0.05) the proportion expressing shorter ( < 0.001) and longer ( < 0.001) intervals. Gilts in REL3wk had a shorter ( < 0.001) interestrus interval (20.7 d) than those in REL2wk and REL1wk (22.6 d). Gilts with shorter intervals ( = 24) had fewer total born while gilts expressing longer cycles ( = 65) had reduced farrowing rates. The number of services (1.9) and number of follicles (19.7) at breeding were not affected ( > 0.10) by relocation. There was no effect of treatment on farrowing rate (85.2%), born alive (12.6), or any litter birth weight measures ( > 0.10). The percentage of sows bred within 7 d after weaning (94.4%) was also not affected by treatment ( > 0.10). These results suggest that the timing of relocation before breeding had no effect on well-being or on the majority of gilts with normal estrous cycles and their subsequent fertility. However, a smaller proportion of the gilts exhibited shorter and longer interestrus intervals in response to relocation 1 or 3 wk before breeding. In cases where gilt fertility may be less than optimal, producers that relocate gilts from pens to stalls before breeding should evaluate interestrus interval as a response criterion.