Alan W. Blackshaw

Heat stress in cattle and the effect of shade on production and behaviour: a review

At high temperatures, evaporative cooling is the principal mechanism for heat dissipation in cattle. It is influenced by humidity and wind speed and by physiological factors such as respiration rate, and density and activity of sweat glands. Following exposure to heat, cattle appear to acclimatise within 2-7 weeks. The failure of homeostasis at high temperatures may lead to reduced productivity or even death. Knowledge of characteristic behavioural signs of increasing heat stress may alert cattle handlers to impending heat distress, particularly in areas of potential climatic extremes of high temperatures and humidities. Reduction of the heat increment of feeding by dietary manipulation may partially protect cattle from forecast heat stress. Under high heat stress, Bos indicus breeds and their crosses have better heat regulatory capacities than Bos taurus breeds, due to differences in metabolic rate, food and water consumption, sweating rate, and coat characteristics and colour. Also, because Bos taurus have a higher heat loading at the skin, they must evaporate substantially more sweat than Bos indicus to maintain normal body temperatures. Welfare concerns exist about heat stress and the provision of shade for feedlot cattle. In hot weather, cattle actively seek shade, which may reduce the radiant heat load by 30% or more. Under conditions of extreme heat load, shading may maintain production and reduce deaths from heat stroke. Shading of feed and water also offers production advantages for British and European breeds of cattle.

Comparison of behaviour patterns of sows and litters in a farrowing crate and a farrowing pen

The behaviours of eight sows (Large White×Landrace) and litters housed in a farrowing crate (600–800 mm width adjustable crates in a 2130 mm × 1850 mm pen) were compared with the behaviours of eight sows and litters in a farrowing pen (2130 mm × 1850 mm) using data from real-time videotapes. Each sow and litter was videotaped on day 1 or 2 after parturition and on six other occasions between days 6 and 30. Piglet activity was similar in the farrowing crate and the farrowing pen systems both in the pen area and at the udder. The farrowing pen piglets rested in the pen area nearly three times as long as the farrowing crate animals (1003 ± 75 vs 315 ± 40; P<0.01; all frequencies per 3 h tape). Piglets in both systems spent a similar amount of time resting at the udder; however, those in the farrowing crate, spent twice as long under the heat lamp (1350 ± 68 vs 671 ± 58; P<0.01). Sows in the farrowing crate were less than half as active as sows in the farrowing pen system when lying down (stretching, kicking, shaking or rolling) (frequencies per 3 h tape, 10.2 ± 1.2 vs 23.9 ± 1.5; P<0.05). Sows in both systems sat, stood up and ate the same amount of time. The sucking activity duration (slow sucking and rapid sucking) of the piglets was significantly longer in the farrowing crate (3.1 ± 0.1 min vs 2.3 ± 0.1 min; P<0.01; duration per 3 h tape). Mortality rates of piglets in the farrowing pen system was 32% vs 14% in the farrowing crate (t(14)=2.116; P=0.053) which suggested that the farrowing pen system was more hazardous for piglet welfare than the farrowing crate for the breed of pig used in this study.

The development of playful behaviour in piglets from birth to weaning in three farrowing environments

Abstract Observations of piglet play behaviour were recorded on real time video over 28 days during six periods for 6 h per period per litter (days 1–5, 6–10, 11–15, 16–20, 21–25, 26–30), from birth, in three farrowing environments: (i) an adjustable parallel crate (800 mm width) in a 2130 mm × 2105 mm pen; (ii) a round crate (1.85 mm diameter) within a pen (2130 mm × 2105 mm); (iii) a pen (2130 mm × 2105 mm) surrounded on the inside by horizontal metal bars 200 mm above the floor. Eight sows and their litters were observed in each environment. Individual play was recorded as spring (sudden jumping or leaping, 9.6% of observations of play frequency, highest in the round crate), run (8.3% of play, no pen differences) and object play (18.8% of play, highest in the parallel crate). These behaviours all began at 3–5 days of age, and peaked at 21–25 days. Social play, which involved nudging or pushing other animals also began at 3–5 days. Nudging contributed 12.3% of observations of play, this behaviour occurring more frequently in the open pen, while pushing comprised 17.1% of play observations and was greatest in the parallel crate. Play with sow began on days 1–2 with piglets climbing, nudging, or biting the sow. This accounted for 22.6% of observations of play and occurred at higher levels in the round crate and open pen than in the parallel crate. Naso-naso contact of piglets with the sow also began early (days 1–2) and averaged 11.0% of play observations with a higher frequency in the parallel crate. The end to a social play episode was usually separation as piglets ceased their activity and walked away (average 72.2% of observations of play endings). Aggression, where the play developed into a fight, accounted for 27.8% of endings in the parallel crate, only 12.5% in the open pen and 13.4% in the round crate. Rest, where the piglets lay down after play, accounted for an average 9.7% of observations of play endings and was much higher in the parallel crate. This study shows that play behaviour develops rapidly in an intensive farrowing environment, which may indicate that piglet welfare is not compromised.

Piglets born from centrifuged and vitrified early and peri-hatching blastocysts.

Cryopreservation of zona-intact porcine embryos has been relatively unsuccessful to date, although some success has been obtained with lipid reduced morulae and early blastocysts. This study adapted some vitrification protocols used successfully with late blastocysts for use with early zona-intact blastocysts, using actin depolymerization, centrifugation, and open-pulled (OPS) straws. Initially, Day 6 peri-hatching blastocysts were collected, cultured for 40 min in 7.5 microg/ml cytochalasin B and vitrified in 6.5 M glycerol and 6% BSA (VS1) in either heat-sealed (HS) or open straws (OS). The post-thaw survival of those stored in HS was 15.4% after 24 and 48 h in vitro; storage in OS significantly improved survival (58.8% for both 24 and 48 h). When similar stage blastocysts were cultured in cytochalasin B and vitrified with 8 M ethylene glycol and 7% polyvinylpyrrolidone (PVP; VS2) in OS, survival was 44.4 and 33.3% for 24 and 48 h, respectively. Day 5 late morulae and early blastocysts were collected, cultured with cytochalasin B, and centrifuged or left intact (control), then vitrified with VS1 in HS or OS, or vitrified in VS2 in OS only. None of the intact control embryos survived thawing and 48 h culture in vitro. Centrifuged early blastocysts vitrified with VS1 showed good post-thaw survival in culture when stored in HS (62.8 and 60.5% for 24 and 48 h, respectively), or OS (75 and 63.6%). When vitrified with VS2 in OS, survival improved (80 and 76.7%). Peri-hatching blastocysts were vitrified in VS1, and early blastocysts were vitrified with VS1 and VS2. All blastocysts were stored in OS. The embryos were recovered and transferred to Day 4 and 5 pseudopregnant recipients (for Day 5 and 6 blastocysts, respectively). Of the five recipients receiving peri-hatching blastocysts, two became pregnant and delivered a total of eight piglets. All three recipients of early blastocysts vitrified in VS1 had a delayed return to estrus; while of the four receiving embryos vitrified with VS2, two were delayed in returning to estrus, and one was confirmed pregnant after 45 days. A litter of five piglets, one male and four female, was produced at 116 days of gestation. To our knowledge, this is the first litter of piglets produced from early blastocysts vitrified without micromanipulation to remove polarized lipid droplets.

Shade-seeking and lying behaviour in pigs of mixed sex and age, with access to outside pens

Observations were made over a 2 month period (50 days) of the standing, lying and shade-seeking behaviour of boars, sows, growers and weaners with access to an outside pen. Some pigs sought shade between 15 and 20°C, and by 26-30°C nearly all the boars (88.3%), sows (87.3%) and growers (91.2%) were in the shade. However, only 65.4% of the weaners were in the shade. Above 35°C, the proportion of weaners seeking shade had increased to 85%. At the lower temperatures (15-20°C) most of the sows in the shade were lying down (84.7%), but only 13.3% of the boars, 54.8% of weaners and 67.6% of growers were lying in the shade. Above 35°C, almost all sows and boars in the shade were lying down (99.6% and 97.9%, respectively) and many of the growers (93.9%) and weaners (91.1%). The younger animals were more restless or lacked the experience to seek shade, either standing or lying down. The proportion of all pigs in the sun (standing or lying) in the morning (08:00-12:00 h) was negatively related to temperature (P < 0.01) and there was no relation with time. In the afternoon (13:00-16:00 h), ambient temperature was not related to the proportion of pigs in the sun, however, time of day showed a weak correlation for boars, sows and weaners, but not for growers. In the morning (08:00-12:00 h) and afternoon (13:00-16:00 h), the proportion of animals standing was related to time rather than temperature. In the morning, the proportion standing decreased and in the afternoon increased with advancing time. If access to outdoors becomes an alternative pig husbandry system, consideration should be given to provision of shade in temperatures above 20°C.

Student Perceptions of Attitudes to the Human-Animal Bond

AbstractStudents (67 per year) in years 1, 2, and 5 (final year) of the veterinary course at The University of Queensland, Australia, were surveyed with six questions asking them to score their perceptions of pet owners, themselves, and veterinarians of the human-animal bond. All students perceived owners, themselves, and veterinarians as usually attached to their pets, although the owners were scored higher, especially by the final-year (year 5) students. The students rated themselves, owners, and veterinarians as usually upset by reports of cruelty to pets, although by year 5 the students realized that veterinarians would be familiar with cruelty to pets.The use of dogs and cats as experimental animals was perceived to upset owners, but only sometimes to upset veterinarians and students. Students and veterinarians were perceived as less likely to buy cards with pets on them, or Christmas presents for their pets, than were pet owners.The results indicate that by final year (year 5) these veterinary stude...

Collagen biosynthesis in cultured rat testicular sertoli and peritubular myoid cells

The incorporation of 3H-proline into protein was regarded as a measure of total protein synthesis and the incorporation into hydroxyproline as indicative of collagen synthesis. Relative collagen synthesis (expressed as percent of total protein synthesized) by Sertoli and peritubular myoid cells cultured from 20-22 day old rat testis was estimated. In both secreted and cellular pools, relative collagen synthesis by Sertoli cells was significantly greater than by peritubular myoid cells. Coculture of Sertoli and myoid cells resulted in a significant increase in relative collagen synthesis when compared to monocultures of each cell type. Addition of serum to peritubular myoid cells resulted in a stronger stimulation of relative collagen production. Sertoli cell extracellular matrix inhibited relative collagen synthesis by peritubular myoid cells in the presence or absence of serum. Radioactivity into hydroxyproline as corrected per cellular DNA also showed similar results. Immunolocalization studies confirmed that both cell types synthesize type I and type IV collagens. These results indicate that stimulation of collagen synthesis observed in Sertoli-myoid cell cocultures is due to humoral interactions, rather than extracellular matrix, and Sertoli cell extracellular matrix regulates serum-induced increase in collagen synthesis by peritubular myoid cells.

The Effect of Group Composition on Behaviour and Performance of Weaned Pigs

Abstract Three methods of grouping piglets at weaning (30–33 days) into a 12-member weaned pool were studied: 6 pigs from 2 litters (6×2); 4 pigs from 3 litters (4×3); 3 pigs from 4 litters (3×4). Each method had three replicates and the weight range at weaning was 7.3–9.9 kg. Agonistic behaviour was recorded over three periods: Period 1 (0–1.5 h immediately after mixing); Period 2 (1 h, 4–5 h later the same afternoon); Period 3 (5 days later for 1 h). Both contact (head thrusting, biting and pushing) and non-contact (chasing, threat and displacement) agonistic behaviours were recorded. Growth rates over 28 days were calculated, but there were no significant differences in growth between the three methods. Contact behaviours contributed the most to establishment of a hierarchy and dropped significantly in frequency over time (P It appears that the 4×3 composition may cause less physical contacts than the other two groupings. This composition has been suggested by some Queensland pig producers as showing less “fighting” behaviour.

Buller steer syndrome review

Abstract The buller steer syndrome is found among confined and pasture-kept cattle. The buller behavior occurs when a steer is repeatedly mounted (“buller”) and ridden by its pen mates (“rider”) until it is injured or killed. The usual practice is to remove the animal being ridden. The ridden animals are typically grouped together in a “buller” pen where little or no mounting is observed. The buller steer syndrome, in todays dollars is estimated at US

Sexual responses of rams to ovariectomized and intact estrous ewes.

70 per steer and thus represents a significant economic loss. Factors associated with an increase in the rate of bulling include: submissive behavior, pheromones, warm weather, large group sizes (over 200–250 head per pen) and other stressful events (mixing, handling, temperature, dust). Buller steer physiology has been studied, with few concrete conclusions. Exogenous estrogen may increase and androgens may decrease the behavior. The vomeronasal organ was not found to be involved in the behavior since lesions to this secondary olfactory organ did not influence bulling rates. A concerted effort is needed to systematically study this problem for economic and welfare reasons.