Influence of rearing system on sows' prolificacy during gestation.
In females reared inindividual crates until early control of gestation and in common crates (8-16heads), prolificacy did not reach values that differ depending on the rearingsystem: there is a statistically insignificant difference in t-test(p>0.05). In gestating sows reared in individual crates, the difference wassignificant during the entire gestation period compared to group rearing:11.51±0.85 compared to only 11.13±0.68 in collective rearing. Though there arebetter results from the point of view of sows’ prolificacy when reared inindividual crates during the entire gestation, this rearing system is notrecommendable because of the high financial efforts caused by technology andbecause separation has negative influences on sows’ behaviour depending on reproductionand health state of gestating females.
Effects of the photoperiodicity on the reproduction in sow. II - Effects on the estrous cycle, pregnancy length and total born piglets.
In the frame of this paper it was researched the relationship between season and some reproductive parameters (oestrus length, pregnancy length and total born piglets) in primiparous and multiparous sows in terms of the photoperiodicity climate in Romania. The research was conducted on a crossbred Yorkshire sows (♀) × Landrace (♂) sow population and consisted of monitoring the oestrus duration, the gestation period and the number of total born piglets related to astronomical seasons: fall, winter, spring and summer. They were found seasonal influences characterized by a longer gestation length in autumn and spring seasons vs. summer and winter, with a difference of about one day between the seasons, and an annual average difference of about one day between primiparous and multiparous sows. Gestation length was inversely correlated with total born piglets. The oestrus length had an annual average of about 2.16 days in primiparous and 2.98 days in multiparous sows, with peak values in seasons of growing photoperiodicity and minimum values in seasons of decreasing photoperiodicity.
A comparison of the behaviour and performance of sows and piglets in crates and oval pens
A comparison was made of sow lying behaviour, piglet aggregation behaviour and performance in crates (no. = 10) and oval pens (no. = 8). Twenty-four hour time-lapse video tapes were made and a farrowing day defined for each sow by noting the 24-h period during which the sow gave birth (09:00 to 09:00 h). Each sow and litter, balanced for parity and time of year, was analysed from 12:00 to 20:00 h during the 24 h immediately following this day. The following analyses were conducted: (1) the number and type of lying behaviour; (2) each litter was scanned every 10 min and at each lying event the number of piglets within 0·3 m of the sow noted; two indices were then calculated, based on the mean of the 10-min scans and the mean for the lying events, for each sow expressed as a proportion of the total litter size. Any dead piglets were removed and cause of mortality established by post-mortem examination. Production data showed that there was no significant difference between litter size at birth and at weaning but overall level of mortality was higher in the pen compared with the crate due to crushing. The majority of crushing events occurred in the first 3 days after farrowing (crate 75%; oval pen 64%). The total number of lying events and related posture changes did not differ between systems; only ‘roll-over’ events (movement from lateral on one side to the other within 10 s) were higher in the oval pen. There was no difference in the proportion of aggregating piglets at the 10-min scans or the lying events. Increased crushing mortality in the pen does not appear to be due to the aggregation behaviour of piglets but to the increased number of sow roll-over behaviours.