Declining sow performance with increasing parity or an increase in the number of poor- quality pigs potentially impacts on farm productivity. This study investigated the phenotypic and genetic background of the sow’s influence on (i) the number of pigs not meeting the industry standards (tail-enders) and (ii) changes in performance with parity. Data were available for 3592 sows and their litters (13,976 litters) from a pig production system in NSW, Australia. The mean, standard deviation (SD), and slope for trait values over time were estimated for the sow characteristic traits: number of born-alive (NBA) and stillborn (SB) piglets and body condition of sow recorded with a caliper (CAL), along with maternal effects on piglet performance, represented by: average piglet birth weight (APBW), number of weaned piglets (WEAN), and tail-enders (TEND). Traits were analyzed in ASReml 4.2, by using an animal model. The number of tail-enders produced by a sow is a heritable trait, with a heritability estimate of 0.14 ± 0.04. Sow characteristics and maternal effects on piglet performance expressed by mean and slope had similar heritability estimates, ranging from 0.10 ± 0.03 to 0.38 ± 0.05, whereas estimates for SD traits were generally not different from zero. The latter suggests individual variability in sow characteristics or maternal performance between parities is largely not genetic in origin. This study demonstrated that more attention is required to identify contributions to the problem of tail-enders, and that slope traits could potentially be useful in the breeding program to maximize lifetime performance.

A small-aliquot freezing technique was employed to store at -80 C red blood cells (RBC) prepared for quality control of antiglobulin sera. These RBC were used to test the specificity and potency of both polyspecific and monospecific antiglobulin sera on the day of use. Following deglycerolization, about 83 per cent of test RBC were recovered. They were then stored as 5 per cent suspensions in 0.9% NaCl at 4 C for up to two weeks and tested for specific agglutination. EIg (RBC sensitized with immunoglobulins) and EC4 (RBC sensitized with the fourth component of human complement) remained reactive for the two-week period. EC43 (RBC sensitized with both the fourth and third components of human complement) tended to lose reactivity only with anti-C3c antibodies following deglycerolization and storage. EC3d (RBC sensitized with the C3d fragment of the third component of human complement), produced in vivo as a result of Mycoplasma pneumoniae infection, remained reactive for the two-week period, whereas EC3d prepared by the alternative pathway of complement activation was useful only for one week. Use of deglycerolized test RBC improved quality-control procedures by saving materials and technician time as well as by providing a constant supply of uniformly prepared test RBC.

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