Texas Tech University Laboratory of Animal Behavior, Physiology and Welfare
Home Research Sow Housing2004 Sow Housing Abstracts

Sow housing abstracts to be presented at the 2004 ASAS Annual meeting in St. Louis

McGlone1, J. J., L. Hulbert1,*, J. Dailey2, R. McPherson1, and J. L. Morrow2.  Trickle versus drop feeding for gilts and sows in gestation crates or pens: reproductive performance and rates of injury.    1Pork Industry Institute, Texas Tech Univ., 2USDA-ARS, Livestock Issues Research Unit, Lubbock.

Sow housing systems and their effects on sow welfare are important to pork producers and consumers.  Specifically, we sought to evaluate the effects of trickle feeding (feed delivered over 30 min) vs. drop feeding (feed delivered in a single moment) for PIC-USA Camborough-22 gilts/sows housed in gestation pens (groups of 5) or individual crates.  Gilts were randomly assigned to one of the four factorially-arranged treatments.  A total of 8 blocks were established.  Pregnant gilts all farrowed in standard farrowing crates and then they returned to their same environment for a second complete parity.  A total of 188 litters were farrowed from parity 1 and 2 females.  Measures included backfat thickness, farrowing rates, numbers of pigs born alive, weaned, stillborn and piglet birth and weaning weights.  Sow weights were collected at farrowing and weaning.  Sow injuries, wounds and scratches were quantified.   No interactions between parity, housing systems or feeding systems were observed.  The interaction between housing and feeding systems was significant (P = 0.01) for only sow farrowing weights;  drop-fed, penned sows were heavier than drop-fed, crated sows while trickle-fed, penned sows were lighter than trickle-fed, crated sows.  Penned sows had more (P < 0.05) backfat thickness than crated sows.  Drop-fed sows weaned pigs were heavier (P < 0.05) than trickle-fed sows.  All other measures of productivity were not different among treatments.  Injuries, wounds and scratches were statistically similar for sows in each treatment group.  Drop-fed, penned sows increased backfat thickness compared with crated sows (perhaps being able to huddle, penned sows required less feed), but this effect was eliminated when penned sows were trickle-fed (and energy expenditure may be increased).  Farrowing rates were 10% lower among penned than crated sows.  We conclude that overall gilt and sow productivity and injury rates were similar for sows in crates and pens, with the exception that farrowing rates may be reduced among sows housed in social groups during gestation.

Key words: Pigs, Sow, Stress, Gestation housing, Welfare

Hulbert*1, L. E., J. M. Hellman1, J. W. Dailey2, J. L. Morrow2 and J. J. McGlone1
Behavior and heart rate of crated gestating sows given and ICV CRH or a CRH receptor antagonist.  1Pork Industry Institute, Texas Tech Univ., 2USDA-ARS, Livestock Issues Research Unit, Lubbock.     

Third-parity, crated Camborough-28 (PIC USA) sows (n=3) were used to determine the effects of intracerebroventricular (icv) corticotropin releasing hormone (CRH) or a CRH antagonist (Astressin, AST) on sow behavior and heart rate.  Specifically we sought to determine if oral-nasal-facial (ONF) stereotyped behaviors were caused by elevations in central CRH.   Sows were surgically fit with an icv canulae in the lateral ventricle during in mid gestation.  Following an 8-d recovery period, sows were fed and then 30 min later given icv saline (SAL), CRH or AST.  Heart rates (Polar 610 IR)  and sow behavior were recorded for 48 h after icv injection. Behaviors included sitting, standing,  feeding, drinking, sham chewing, ONF directed towards the bars, floor, or feeder and total ONF duration and frequency.  Central CRH increased (P < 0.01) ONF directed towards the bars and the floor and total ONF compared with icv SAL.  AST did not (P > 0.10) change ONF or general activity.  Total ONF duration was 187.8, 2,253.1 and 203.1 s for SAL, CRH and AST, respectively (P < 0.001;  SE = 117.8).  Lying down duration was lower for CRH-treated sows than for sows in the other treatments (3,261, 1,153, 3,175 s for SAL, CRH and AST, respectively, P < .001; SE = 127). Heart rate was increased among CRH-treated sows compared with the other treatment groups (75, 114 and 86 bpm; P < 0.01; SE = 5.8).  Increasing central CRH dramatically increased ONF, general activity and heart rate.  Central AST did not reduce (or increase) ONF or heart rate.  We conclude that elevated basal levels of CRH among crated sows does not cause ONF behaviors (because AST did not reduce this behavior).  However, elevated central CRH increases both ONF behaviors and heart rate.  Sow bar-biting behaviors, at the levels observed in crated sows,  is not caused by elevated central CRH.    

KeyWords: Pigs, CRH, Welfare

J. J. McGlone.  Behavior of sows during lactation.  Pork Industry Institute, Texas Tech Univ., Lubbock.

 Sow behavior is influenced by their genes and by their environment.  During lactation, sows undergo significant changes in physiology that cause large behavioral changes.  The objective of this review is to summarize the literature on sow behavior during lactation and the effects of management practices (such as weaning age and housing system) on sow behavior.  Also, this review will summarize sow behaviors that lead to problems with the lactating sow or piglets.  Sows undergo four major phases of behavior in the peri-lactation phase.  First, prior to farrowing, sows undergo nest-building behavior that may involve building of an actual nest if sows are given building materials or expression of phantom nest-building behaviors in the absence of building materials.  The second phase involves the establishment of the maternal-neonatal bond.  This phase requires 12 to 24 h and is critical for piglet survival and growth.  Maternal pheromones are secreted and the piglet is able to suckle in the presence of maternal pheromones.  The piglet also is able to recognize its mother by her odor signature.  The third phase is the lactation phase in which sows and piglets organize suckling with an interval of 40 to 50 min between nursing bouts.  As piglets become larger, they will have larger, but less frequent meals – this trend continues from birth through market age.  If given the opportunity, sows will spend less time with piglets as lactation progresses.  The fourth phase is the weaning phase which can be gradual or abrupt and includes weaning and the weaning to estrus interval.  Natural weaning by the sow can take place at any time from 3 d to 6 months of age.  Sow genotype and the housing system can have major impacts on pig behavior during each phase.  Weaning age will significantly impact phase 3 and 4 sow behaviors.  Sow welfare including stress-related behaviors, wounds, scratches, injuries, weight loss and body condition are influenced by the behavior sows express as a result of their genotype, housing system and management practices. 

Key Words: Pigs, Lactation, Behavior