P. A. Phillips

Effect of straw on the behaviour of growing pigs

Abstract The effects of straw on the behaviour of young growing pigs were studied in two experiments. In Experiment 1, groups of three pigs, aged about 7 weeks, were housed in raised decks with or without straw bedding. Time-lapse video recording showed no major differences between treatments in the amount or daily pattern of overall activity and feeding. Detailed observations showed that bedding reduced the incidence of rooting and chewing on pen-mates, but had little effect on other social activities such as mounting and aggressive biting. Experiment 2 compared groups of eight growing pigs aged about 10 weeks, housed in floor pens with or without a small amount of straw provided daily in a rack. Pigs with straw concentrated more of their daily activity into the period when straw was fresh, but the total amount of overall activity and time spent feeding were not affected. Rooting and chewing of pen-mates were the only social activities reduced by the provision of fresh straw. In these studies, where straw was not required to compensate for deficiencies such as low temperatures or hunger, the one major function of straw was to provide a stimulus and outlet for rooting and chewing, with a resulting reduction in such activities directed at pen-mates.

Farrowing behaviour and stillbirth in two environments: an evaluation of the restraint-stillbirth hypothesis

A total of 59 farrowings were studied in either a conventional, narrow farrowing crate (0.43 m wide) or a much wider alternative design with sides spaced 1.2 m apart at the sows standing height but narrowing near the floor to limit the sows lying area. Using video recoding, we monitored each “birth interval” (i.e. the period between two successive births) and noted the intervals length, the sows posture and postural changes during the interval, and whether the interval ended with a live-born or stillborn piglet. The wide and conventional crates did not differ significantly in median interval between piglets (15.9 versus 16.0 min, respectively), incidence of stillbirth (5.8 versus 7.0%), in any measures of posture or postural change, or in piglet survival and weight gain to 3 days of age. Sows were most active during the first two birth intervals; as farrowing continued they made progressively fewer postural changes and spent more time lying. Sows differed greatly in the frequency of postural changes and the time they spent in different postures; however, these measures were largely unrelated to stillbirths, except that stillbirths were rare if the sow sat during much of the interval (P < 0.001). Birth intervals were longer, on average, before a stillbirth (median of 34 min) than before a live birth (13 min; P < 0.001). The greater incidence of stillbirths late in the farrowing was associated with a greater proportion of long birth intervals late in the farrowing, and greater likelihood of stillbirth even for shorter and medium intervals. Stillbirths were more common in longer farrowings (P ≈ 0.01), evidently because these tended to involve larger litter sizes and more long birth intervals of over 60 min. However, the proportion stillborn in a litter was not correlated with median birth interval. The results of this and related studies suggest that greater freedom of movement in the farrowing environment does not consistently produce shorter duration of farrowing or a lower incidence of stillbirth.

Lethargy and low water intake by sows during early lactation: A cause of low piglet weight gains and survival?

Abstract Daily water intake was monitored for 40 sows during 5 days before and 14 days after farrowing. Intake averaged 9–12 l day −1 before farrowing, dropped to a mean of 6 l on the day of farrowing and increased gradually over 4 days to a plateau of ∼ 14 l day −1 . Sows varied greatly in the degree of reduction in intake during the day of farrowing and the first 3 days of lactation, and those sows with low water intake on these days had low average weight gains by the piglets in the same period. Most of the piglet deaths in the study (14 of 19) occurred in the 10 litters whose dam consumed ≤6 l day −1 of water from Day 0 to 3 of lactation. Monitoring of 14 sows by time-lapse video recording showed that gross physical activity (percentage of time standing and sitting) varied greatly among sows during the first 3 days after farrowing, with the less active sows having significantly lower water intake. We suggest that some sows are excessively lethargic in the first days after farrowing and fail to consume adequate water, and that this could contribute to low milk production in early lactation.

Preference by sows for a partially enclosed farrowing crate

A preference testing apparatus was designed to give sows continuous access to three farrowing crates with different degrees of visual enclosure. A ‘fully enclosed’ crate had solid black panels on the sides and top of the crate, a ‘solid-sided’ crate had the side panels only and an ‘open crate’ had no solid panels over the crates tubular framework. The crates radiated from a central area sufficient for sows to enter or leave any crate freely. Video recording was used to determine sow position from 3 days before to 6 days after farrowing. The results indicated that younger sows (second or third parity) preferred the enclosure offered by the solid side panels during and for several days after farrowing (P < 0.05). Older sows, which had previously farrowed a number of times in an open crate, had no clear preference. A solid panel overhead did not improve, andmay have reduced the acceptance of a crate with solid sides. It is concluded that less experienced sows prefer a degree of enclosure on the sides of the farrowing crate, but that this preference largely disappears with repeated experience of open crates.

Floor Temperature Preference of Sows at Farrowing

A preference testing apparatus was used to provide sows with continuous access to three identical farrowing crates, each with a different floor temperature. The concrete floor under each crate contained copper pipe through which temperature-controlled water was circulated to achieve unoccupied floor temperatures of 22 degrees C (+/-3.5), 29 degrees C (+/-1) and 35 degrees C (+/-1). Eighteen sows were tested in the apparatus. Video recording was used to determine sow position from 7 days before farrowing (Days -7 to -1) to 14 days after (Days 1 to 14). On Days -7 to -1, sows showed no significant preference among the three temperatures when selecting a resting area. Once farrowing had begun, there was a significant increase (P<0.01) in the use of the 35 degrees C floor and it became the most preferred resting area for Days 1 to 3. After this interval, use of the 35 degrees C floor declined significantly (P<0.01), and use of the cooler floors increased, resulting in no significant thermal preference during Days 4 to 6. There was a further decline in the use of the 35 degrees C floor after Days 4 to 6 (P<0.01) to the extent that the coolest floor (22 degrees C) became the most preferred from Days 7 to 14. In summary, sows showed a pronounced increase in preference for a warm floor during the 3 days after the start of farrowing. This change in preference may explain how free-living sows select a suitable thermal environment for their young, and why sows try to avoid metal flooring at the time of farrowing.