Matrilinear social dominance and spatial relationships among Angus and Hereford cows.

Two groups of Angus and Hereford cow families on summer pastures were observed to determine the effects of kinship and breed on social dominance and spacing relationships among individuals within groups. Each group was composed of 20 cows and contained two granddam-dam-daughter families and two dam-daughter families of each breed. Herefords tended to weigh more (P less than .10) than Angus; 518 (SD = 114) and 467 (SD = 92) kg, respectively. However, Angus were socially dominant (P less than .01) to Herefords, with 51.9 (SD = 20.1) and 33.4 (SD = 15.9) mean dominance values for cows of the respective breeds. In no case was a Hereford cow determined to be dominant to an older Angus cow. Within families of both breeds, dams and granddams were always dominant to their progeny. Relative distances among cows were determined on 30 occasions over a 2-mo period of time. Based on nearest neighbor frequency, there was a tendency for members of families to aggregate, but in general family explained only a slight to moderate amount of variation in spacing characteristics. Breed affected mean distance to all cows (P less than .01), distance to group center (P less than .05), distance to same breed group center (P less than .01), distance to opposite breed group center (P less than .05) and mean distance to all cows of the same breed (P less than .01), but breed did not affect mean distance to all cows of the opposite breed. Distances for Angus were less than those for Herefords for each of the significantly affected spacing characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Diurnal behavior patterns of feedlot bulls during winter and spring in northern latitudes.

The diurnal behavior patterns of feedlot bulls were investigated at 52 degrees N during winter and spring. Two trials were conducted during periods when the daylight portion of the day increased by over 7 h. In trial 1, 324 bulls were observed hourly for 24 h on nine occasions at 2-wk intervals. The average proportions of bulls eating, drinking, standing and lying were 9.8, 1.9, 27.4 and 60.0%, respectively. Major periods of eating, drinking and standing were associated with the times of sunrise and sunset and shifted with seasonal changes. Initiation and termination of the afternoon period of eating was greatly affected by changing times of sunset and not by the daily addition of feed, which always occurred at approximately 1600 h. A significant period of eating, involving up to 15% of the bulls at one time, occurred near midnight during the longer winter night but decreased in duration and intensity as day-length increased. In trial 2, continuous observations for 24 h were made at 2-wk intervals on two groups of nine bulls. When the spread in time between morning and evening activity increased due to longer daylength, bulls were active at midday. This became more pronounced on days when the photoperiod exceeded 10 h. Minor periods of activity were evident at night. Mounting and agonistic encounters increased dramatically in frequency near sunset and in general were associated with the major periods of eating and standing.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of floor area allowance and group size on the productivity of growing/finishing pigs.

Six group sizes and three levels of floor area allowance were studied in a 6 x 3 factorial arrangement. Group sizes were 3, 5, 6, 7, 10, and 15 pigs per pen. Floor area allowances were .030, .039, and .048 m2 x BW(.667). All pens were square and equipped with a single space feeder and nipple drinker near one corner. Pigs were fed a pelleted diet. Initial weights averaged 25.0 kg, and pigs remained on test for 12 wk. Pigs were weighed, feed intake was determined, and size of pens was increased at 2-wk intervals. Pen size was adjusted to provide the space required for the midpoint of each weigh period. Two replicates of the study were conducted. The ADG was reduced with increasing group size (899, 851, 868, 872, 857, and 821 g, SEM = 16.4, for 3, 5, 6, 7, 10, and 15 pigs, respectively; P < .05), but the CV for gain (mean = .185) did not differ among group sizes. The ADFI also decreased with increasing group size (2.49, 2.34, 2.32, 2.28, 2.28, and 2.21 kg, SEM = .036, for 3, 5, 6, 7, 10, and 15 pigs, respectively; P < .05). Feed efficiency (gain/intake) was highest for group sizes of 7 and 10 pigs (.381) and lowest for pens of three and five pigs (.363; P < .05). The ADG and ADFI (832 g and 2.25 kg, respectively) for the most crowded space allowance were reduced compared to more spacious allowances (ADG and ADFI of 875 and 877 g, and 2.35 and 2.36 kg, for .039 and .048 m2 x BW(.667), respectively; P < .05). Efficiency did not differ among space allowances. These results confirm previous studies reporting a negative effect of increasing group size on productivity, but our study suggests that gain and intake reach a plateau at less space allowance than previously reported.

The importance of animal cognition in agricultural animal production systems: an overview.

To describe and then fulfill agricultural animals' needs, we must learn more about their fundamental psychological and behavioral processes. How does this animal feel? Is that animal suffering? Will we ever be able to know these things? Scientists specializing in animal cognition say that there are numerous problems but that they can be overcome. Recognition by scientists of the notion of animal awareness has been increasing in recent years, because of the work of Griffin and others. Feeling, thinking, remembering, and imagining are cognitive processes that are factors in the economic and humane production of agricultural animals. It has been observed that the animal welfare debate depends on two controversial questions: Do animals have subjective feelings? If they do, can we find indicators that reveal them? Here, indirect behavioral analysis approaches must be taken. Moreover, the linear additivity of several stressor effects on a variety of animal traits suggests that some single phenomenon is acting as a "clearinghouse" for many or all of the stresses acting on an animal at any given time, and this phenomenon might be psychological stress. Specific situations animals may encounter in agricultural production settings are discussed with respect to the animals' subjective feelings.

Scrotal measurements in beef bulls: heritability estimates, breed and test station effects.

Heritability estimates for scrotal circumference and testicular tone at weaning (225 d) and yearling (365 d) were determined from records on 565 bulls from a purebred Angus herd; year, station and breed effects were determined from scrotal circumference records on 2,420 bulls at five tests stations. Year, breed and breed X year effects on scrotal circumference, length, width and volume were determined from records on 347 bulls at one station. Heritability estimates (+/- SE) were .60 +/- .17, .28 +/- .18 and .25 +/- .18 for weaning scrotal circumference, right and left tone, and .38 +2- .16, .72 +/- .18 and .52 +/- .17 for yearling scrotal circumference, right and left tone, respectively. With the exception of low negative correlations of 205-d weight and longissimus muscle area with yearling scrotal circumference (-01 and -.02, respectively), correlations of growth and live-estimated carcass traits with weaning or yearling scrotal dimensions were low and positive (0.8 to .35). In the second data set, Simmental and Angus had greater (p less than .01) yearling scrotal circumferences than Charolais or Herefords; means were 35.3, 35.0, 33.7 and 33.5 cm, respectively. Station and station x breed effects were significant (P less than .01), with the latter effect indicating that breeds did not rank similarly in scrotal circumference at different test stations. In the third data set, scrotal circumference and volume were essentially the same as scrotal length and width in ranking breeds. year X breed interactions were nonsignificant for all scrotal traits, indicating that breeds were ranked similar in different years with respect to scrotal dimensions. These results indicate that bulls of different breeds should not be compared to established standards; a more acceptable procedure would be the use of deviations from the respective breed-station-year means.

Effects of individual housing design and size on special-fed Holstein veal calf growth performance, hematology, and carcass characteristics.

The objective was to evaluate the effects of individual housing design (stalls vs pens) with widths of 56, 66, and 76 cm (2 x 3 factorial treatment arrangement) on growth, hematology, cleanliness, ambulation, abomasal hairball, and carcass measurements. Three groups of 36 Holstein bull calves (n = 108) were randomly allotted within group to treatments. There were no effects (P > .05) of housing design, width, or two-way interactions for BW, ADG, carcass weight, or dressing percentage. Blood samples were collected at approximately 33-d intervals. Mean values for hemoglobin, hematocrit, white blood cell count (WBC), and red blood cell count (RBC) were not different among treatments (P > .05), with the exception of d 28 hemoglobin, which was greater in the calves housed in 66-cm vs 76-cm stall. There were differences (P < .05) due to design and design x width effects for hind-quarter cleanliness; manure accumulation tended to be greater in pens vs stalls as width increased. There were increases (P < .05) in left front knee swelling scores as stall or pen size decreased; no important differences were observed in ambulatory ability among treatment groups. There were design effects (P < .05) for excitability scores, with calves in stalls being more excitable. There were no important treatment effects (P > .05) for liver, spleen, and lung condition, number of abomasal hairballs, or 0- and 24-h after slaughter flank or brisket color. These results indicate that housing designs and widths did not affect veal calf growth performance, WBC, RBC, hemoglobin, hematocrit, ambulation, or muscle color.

Artificial pigs in space: using artificial intelligence and artificial life techniques to design animal housing.

Computer simulations have been used by us since the early 1970s to gain an understanding of the spacing and movement patterns of confined animals. The work has progressed from the early stages, in which we used randomly positioned points, to current investigations of animats (computer-simulated animals), which show low levels of learning via artificial neural networks. We have determined that 1) pens of equal floor area but of different shape result in different spatial and movement patterns for randomly positioned and moving animats; 2) when group size increases under constant density, freedom of movement approaches an asymptote at approximately six animats; 3) matching the number of animats with the number of corners results in optimal freedom of movement for small groups of animats; and 4) perimeter positioning occurs in groups of animats that maximize their distance to first- and second-nearest neighbors. Recently, we developed animats that move, compete for social dominance, and are motivated to obtain resources (food, resting sites, etc.). We are currently developing an animat that learns its behavior from the spatial and movement data collected on live pigs. The animat model is then used to pretest pen designs, followed by new pig spatial data fed into the animat model, resulting in a new pen design to be tested, and the steps are repeated. We believe that methodologies from artificial-life and artificial intelligence can contribute to the understanding of basic animal behavior principles, as well as to the solving of problems in production agriculture in areas such as animal housing design.

Effects of individual housing design and size on behavior and stress indicators of special-fed Holstein veal calves.

The objectives of this study were to determine effects of housing design (calves tethered in open stalls vs untethered in individual pens) and widths of 56, 66, and 76 cm (2 x 3 factorial arrangement of treatments) on indicators of stress and behavior in special-fed veal calves. Three production cycles (groups) were used, each with 36 Holstein bull calves. Calves (n = 108) were randomly allotted to treatments upon arrival at the facility. Blood samples were collected four times (wk 4, 9, 13, and 18) during the 18-wk production cycle. Blood serum values for cortisol and alpha1-acid glycoprotein (AGP) exhibited few treatment differences. Blood leukocyte differential counts at 4 and 18 wk (segmented neutrophils [N], banded neutrophils, lymphocytes [L], basophils, and the N:L ratio) were not different (P > .05) among housing designs or widths. However, there were differences (P < .05) in monocytes and eosinophils during the 28-d period after arrival; calves in stalls 76 cm wide had the greatest percentage of both leukocytes, and calves in the 66-cm stalls had the lowest monocyte percentage. Calves were recorded on videotape during wk 4, 13.5, and 18 to determine frequencies and durations of postures and behaviors (e.g., lying, standing, chewing, tongue playing, grooming, and investigative activities). There were no consistent differences (P > .05) in postures or behaviors among calves in different housing designs or widths. Calves spent approximately 71 and 31% in lying and standing positions, with no preference for the right or left side while recumbent. There was a tendency for calves in wider stalls or pens at wk 9 and 18 to exhibit more self-grooming activities. Tongue playing and investigative and chewing activities were exhibited in all treatments, but no differences (P > .05) were observed. However, calves housed in the 56-cm pens displayed difficulty in changing from lying to a standing position and were unable to extend one or more legs while recumbent. Even though there were few differences in behavioral, physiological, growth, or anatomical traits in this study, further increases in age and(or) weight of finished calves will require a reassessment of the appropriateness of individual veal calf housing design and dimensions.

Social organization.

Because animal agriculture is largely concerned with the most efficient management of groups of animals, an understanding of the function and characteristics of social organization associated with each species is important for the optimal design of production systems.