Assessing sensory capacity of animals using operant technology.

Operant technology is often employed in farm management (e.g., waterers in which an animal pushes a valve with its nose or snout [response] to receive water [reinforcement]). An animal learns when successive approximations to the desired response are reinforced, thereby establishing the operant behavior (shaping). Animals are challenged by schedules of reinforcement that increase level of operant response. The method has been used to obtain quantitative measures of preference for prepared feeds, flavors, and harvest methods and feed processing. Basic information on what an animal sees in terms of color, patterns, and illumination are cited. Innovative research on animals' ability to smell and to hear are reviewed. Studies on regulation of environmental conditions by the animals themselves through operant methods will contribute to needed knowledge about animal welfare. Several examples of these studies are included in this review. Results of numerous studies indicate that operant technology can be a powerful tool to assess the sensory capacity of animals.

The influence of sometribove dose and days in lactation on behavior of cows implanted with pelleted sometribove.

Data were from observations of behavior of 99 lactating Holstein cows during implantations with bST. Implantations were at 14-d intervals during 1 yr. Cows on one study received 0, 120, 240, or 360 mg; cows on a second study received 0, 160, or 320 mg of bST per implantation. A checklist of behaviors was completed by the recorder and observer for each cow during implantation. Cows were also given an overall temperament score during each session. Lunging occurred in 49% of the sessions, but bellowing, kicking, and kneeling occurred least. More cows scored in the docile range than in the excited range. Cows habituated to head bobbing, back sagging, lunging, moving back in chute, flinching, head up, and bellowing, but not to shifting feet, kicking, shaking the head, head back, or ears back.

Effects of concentrated separator dried beet pulp on nutrient digestibility, milk production, and preference of Holstein cattle.

Concentrated separator by-product was fed to cattle to determine TDN, milk production, and feed preference. The TDN content of concentrated separator by-product was determined using a substitution method involving a basal diet of alfalfa and grass hay and a treatment diet of alfalfa and grass hay plus 10% added concentrated separator by-product. Four ruminally cannulated cows in a replicated 2 x 2 Latin square design were used. The estimated TDN content of concentrated separator by-product was 59.3%. Twenty midlactation dairy cows were fed either a control ration containing 20% molasses dried beet pulp or a treatment ration containing 20% concentrated separator by-product dried beet pulp. Cows in the treatment group produced significantly less daily milk and 3.5% FCM than the control group. Percentages of milk fat, protein, lactose, and SNF were not different between treatments. Eight Holstein heifers were used to determine feed preference. Heifers were given a choice among 20% molasses dried beet pulp (control) or 10, 15, or 30% concentrated separator by-product dried beet pulp. Heifers showed no preference between 10 or 15% concentrated separator by-product dried beet pulp and control, but preferred the control over the 30% concentrated separator by-product dried beet pulp.

Effects of isolation of calves on growth, behavior, and first lactation milk yield of Holstein cows.

Holstein (n = 323) calves in the herds of four experiment stations were reared individually (control) or in isolation to 70 d of age to determine whether isolation affected growth, behavior, and first lactation yield. Treatment differences were not observed for average daily gain for BW at d 28, 56 or 70. Postweaning approach distance was measured in two herds (n = 122; n = 28). Detailed pre and post-weaning behaviors were reported in one herd (n = 26). Isolation did not affect subsequent milk yield or culling percentages. In a second experiment, seven pairs of monozygous twins and a set of identical triplet calves were obtained by transferring split embryos into recipients, one member of each pair was reared in a group, and the twin was reared in isolation. Early rearing previously had been found to affect growth, feed intake, dominance rank, and learning ability of calves, and, in our study, the subsequent milk yield of calves reared in isolation tended to average more than for calves in groups. Intraclass correlations between monozygous twin pairs for milk, fat, relative value milk, and relative value fat were lower than anticipated. These data indicate that preweaning isolation did not affect first lactation milk yield traits.

Effect of poultry waste feeding on intake, body weight and milk yield of Holstein cows.

Forty lactating Holstein cows were fed 0, 5.9, 11.7, or 17.4% processed poultry excreta in total mixed rations. The effect of treatment was evaluated on feed intake, BW, milk yield, and composition. Processes poultry excreta appeared to be well accepted by cows even when included in rations at 17.4% of total DM. Mean DM intake averaged 19.3, 19.7, 19.5, and 19.7 kg/d for cows fed 0, 5.9, 11.7, and 17.4% processed poultry excreta, respectively. Body weight change averaged 2.0, 1.7, -1.7, and 1.4 kg/wk from 90 to 180 d of lactation for cows fed from 0 to 17.4% processed poultry excreta, respectively. Fat-corrected milk (4%) yield was similar among treatment groups, averaging 24.2, 26.1, 24.6, and 25.1 kg/d for cows fed 0, 5.9, 11.7, and 17.4% processed poultry excreta. No differences were found for milk and fat yields of percentage fat among treatment means. No off flavors in milk could be attributed to processed poultry excreta added to feed. Processed poultry excreta fed up to 17.4% of total mixed rations supported both adequate feed intake and high milk yields of mid-lactation cows.

Associations of bovine blood and milk polymorphisms with lactation traits: Holsteins.

First lactation milk yield and percentages of fat, solids-not-fat, and protein were analyzed to determine the possible relationships between 14 polymorphic loci and production in Holstein cows. The polymorphic systems examined were blood groups (A, B, C, F, J, L, M, S, and Z), serum transferrin, and milk proteins (beta-lactoglobulin, alpha s1-casein, beta-casein, and kappa-casein). Several statistical models were utilized. Although results differed according to the analysis conducted, in general, no system had a significant association with first lactation milk yield expressed as a herdmate deviation. Most striking were the relationships between milk protein polymorphisms and percent solids-not-fat and protein deviations; beta-casein and kappa-casein alleles had statistically significant associations with these traits. The F system was significant for percent fat deviations, whereas J x L system interactions were significant for all traits. Degree of heterozygosity over the 14 systems was positively associated with percent protein deviations.

Factors affecting survivability of transferred whole and demi-embryos in a commercial dairy herd.

Sixty Holstein donor cows were superovulated and embryos were collected during a 6-d (27 cows) and a 4-d (33 cows) period approximately 60 d apart. Forty-three donor cows yielded embryos. Ninety-one embryos graded 1 or 2 were split and transferred to 181 recipient Holsteins. Demi-embryos were graded 2, 2-, 3 and 3- prior to transfer. Pregnancy and calving percentages were similar for all demi-embryo grades, averaging 59 and 53% from the two donor groups, respectively. Twin demi-embryo pregnancies averaged 36 and 19% for embryos split at the compacted morula and blastocyst stages, respectively. Twin demi-embryo calvings averaged 30 and 15% for these same groups. Progesterone levels of recipients (of either whole or demi-embryos) of second period donors were measured. Pregnancy rate increased generally with level of progesterone; however, calving percentage was slightly greater for recipients with intermediate levels of progesterone (2-6 ng/ml). Multiparous cow (20) recipients of demi-embryos had 45% pregnancy and 40% calving, while nulliparous heifer (161) recipients averaged 59 and 53% pregnancy and calving, respectively.

Physiological and glucocorticoid response to treadmill exercise of Holstein heifers.

Effect of exercise for 8 wk prepartum on heart rate, respiration rate, rectal temperature, and serum glucocorticoid concentration was determined for nine Holstein heifers. Exercise was on a treadmill 30 min daily, 5 d/wk, for approximately 8 wk. Physiological measures were taken at rest and immediately postexercise; blood samples were taken via jugular vein cannulas at 2-h intervals 26 h preexercise, at 10-min intervals during exercise and 21.5 h postexercise, all at initiation of the experiment and again near the end of pregnancy. The three physiological measures increased during exercise at both the initiation and termination of the 8-wk exercise period. Mean serum glucocorticoids of heifers increased from 5.4 to 21.3 ng/ml during initial exercise but increased from 4.4 to 5.2 ng/ml following approximately 8 wk exercise. These glucocorticoid data mimic trends found in other species, i.e., physically fit subjects or animals trained to chronic exercise have lower glucocorticoids than sedentary or untrained subjects during intense or exhaustive exercise.

Ability of cattle to distinguish among different wavelengths of light.

Eight heifers were trained using operant conditioning to press a plate to receive feed as a reward. Different wavelengths of light were the correct and incorrect stimuli. Positive and negative responses to the stimuli were registered electronically. Daily sessions of 20 min were conducted in a chamber from which external light had been excluded. A 75% correct choice was the criterion for acceptable discrimination. Ratios of correct to incorrect responses were computed. Three colors, i.e., green (535 nm), red (610 nm), and blue (450 nm), were compared pairwise during eight trials. Trial 7 was a repeat trial of green versus red and trial 8 was a comparison of green versus green. Subjects gave random response to green versus green. Five subjects distinguished red from blue: 1, 2, 3, 4, and 5 at 76, 91, 78, 88 and 81% correct choice, respectively. Three subjects distinguished blue from green: 1, 2, and 5 at 89, 88, and 85% correct choice, respectively. Three subjects distinguished green from red in a repeat trial: 1, 5, and 7 at 90, 84, and 85% correct choice, respectively. Subjects failed to discriminate these colors in the first red versus green trial. Results indicate that heifers can learn to discriminate between colors.

Effect of early rearing experience on subsequent behavior and production of Holstein heifers.

Sixty-seven heifer calves were assigned at birth to one of four rearing treatments: groups of six, individual hutch, isolation, and isolation with handling (10 min daily interaction with calf feeder). Calves were on the same diet and except for group calves were in 1.2 X 2.4-m hutches. Group calves were in open shed housing with 3m2/calf. Calves were weaned at approximately 10 wk and then assimilated into regular herd routine. An open field test of 3 min for each calf was conducted on 3 consecutive days at weaning. Samples for blood plasma glucocorticoids were taken before and after open field testing. Forty-eight heifers milked twice daily completed 305-day lactations. There were no differences in weaning weight or average daily gain to weaning. Group calves urinated and defecated more during open field tests, but number of vocalizations was not different. There was a significant rise of glucocorticoids for all calves, but treatment effects were nil. Cows reared in isolation (treatments 3 and 4) produced significantly more milk (922 kg 3.5% fat-corrected milk), had a 1205 kg advantage in relative milk, but were not different from group or individually reared cows in relative milk fat. A hypothesis to explain these results is proposed.

Effect of exercise on glucocorticoids and other cellular components of blood.

The effect of exercise during the dry period on glucocorticoids, packed cell volume, hemoglobin concentration, total leucocytes, and differential leucocyte count was examined with 87 Holstein cows. Cows were divided randomly into groups: 1) control, 2) 3.2 km at 3.5 km/h, 3) 9.6 km at 3.5 km/h, and 4) 3.2 km at 5.5 km/h. Sampling for blood analysis was at weekly intervals preexercise and immediately postexercise. Both glucocorticoids and hemoglobin concentrations were increased by exercise. Correlations between glucocorticoids and most other traits were practically zero. No eosinopenia was noted with increasing glucocorticoids. Lymphocyte numbers were correlated negatively with all traits measured. Glucocorticoid concentration increased from pre- to postexercise with both distance and speed. Although glucocorticoid concentration varied among cows, neither day sampled, days dry, weight, nor age affected glucocorticoids. Increased hemoglobin of postexercise cows could not be attributed to speed or distance exercised. Traits measured in this study, other than glucocorticoid concentration, are ineffective in evaluating response to increased exercise.

Facility for exercising dairy cows.

That dairy cows housed in confinement might benefit if they were exercised during the dry period prompted development of a facility for exercising dairy cows. Two methhods of the exerciser, which consist of a circular lane and a driving mechanism powered by a variable speed electric motor, are described. A speed of 3.5 k, per h provides a steady but comfortable pace for pregnant dairy cows and heifers. Many animals refused to go at speeds greater than 5.5 km per h.

Effects of dominance rank changes, age, and body weight on plasma corticoids of mature dairy cattle.

The purpose was to determine whether forced change in dominance rank affected total corticoids of plasma of dairy cattle. Nineteen cows in late lactation were assigned randomly to one of two lots. Restriction of manger space enhanced observations of dominance rank during feeding for three 1-h periods per wk over 6 wk. After 3 wk, a group of the five highest ranking cows from each lot were combined into a new aggressive lot; two groups of subordinate cows formed a docile lot. Blood samples were from tail vein, and concentrations of total corticoids were determined by competitive protein binding. Changes of dominance rank varied from zero to eight places in the 10-cow assemblage after new lots were formed. Body weight was the most significant variable affecting dominance rank. There was no discernable relationship between total corticoids and dominance rank, body weight, or age. The pattern of variation of total corticoids was similar for all groups during the first 3-wk period, but in the second period docile and aggressive groups had dissimilar patterns. Interaction of group by week for total corticoids was significant; however, a cause and effect relationship could not be established. Total corticoids did not appear to be a valid or useful determinant of social stress.

Inheritance of limber legs in Jersey cattle.

Pedigree information from 105 cases of limber leg Jersey calves indicate that this semilethal abnormality is inherited as a simple autosomal recessive. The increased incidence of this abnormality in recent years suggests a rise in the gene frequency, probably due to the popularity and widespread use of a carrier bull Favorite Commando, his daughter Marlu Milady, and many of their descendants. Steps to control this abnormality have been taken by the American Jersey Cattle Club.

Social rank and physiological traits of dairy cows as influenced by changing group membership.

Social behavior was observed in two groups of 17 cows during 13 wk to determine dominance rank. On the basis of dominance ranking during two bi-weekly intervals (wk 3 and 4, 7 and 8), a total of six cows was exchanged between groups (two during the first and four during the second exchange). The effect on milk yield, milk leucocyte concentration, and milk prolactin of dominance rank and introduction of "strange" cows into a group was studied. Dominance rank was greater for older, heavier, taller cows in a later stage of lactation. Fat-corrected-milk yield was greater for dominant cows but milk prolactin was lower. Dominace rank for cows moved to a new group did not change appreciably. Persistency of milk yield was associated negatively with dominance rank for five of six exchanged cows. Since the average persistency of milk yield for all cows dropped 5% from wk 7 to wk 8, it appears exchange of cows between groups affected both exchanged and nonexchanged cows in a random manner. Neither dominance rank nor exchanging cows between groups had a significant effect on leucocyte concentrations in milk. Milk-prolactin concentrations were most highly correlated with dominance rank, stage of lactation, body weight, and height at withers.

Genetic and environmental effects on serum cholesterol of dairy cattle of various ages.

Serum cholesterol of dairy cattle, particularly when measured on animals of the same approximate age, is a heritable trait. Heritabilities were .50 for first lactation cows and .19 for heifers from 2 to 22 mo of age. Serum cholesterol increases with increasing age. Serum cholesterol was 192.8 mg/100 ml in cows and 121.4 mg/100 ml in heifers. Serum cholesterol was relatively low at the onset of lactation, increased at mid-lactation, and leveled off or decreased in late lactation. Month of calving, year of sampling, and ration did not influence serum cholesterol of first lactation cows. However, variation in both month and year of sampling was significant for heifers.

Environmental and lactational variables affecting prolactin concentrations in bovine milk.

Relationships were examined between prolactin concentrations in bovine milk and various environmental and lactational variables. Prolactin was quantified by radioimmunoassay in 1.316 milk samples from two experiments. Environmental temperatures preceding milking, stage of lactation, daily miik yield, and dominance rank of the cow were correlated significantly with milk prolactin concentration. Stepwise multiple regression analysis was used to determine, in order of importance, the variables having significant independent effects on milk prolactin. Ambient temperature extremes, high and low, exerted the greatest effects and were each associated with elevated concentrations of prolactin. In Experiment I,conducted throughout the year, the variable representing maximum temperature preceding milking accounted for 14.3% of the variation in milk prolactin. In Experiment II, conducted during late fall and early winter, the minimum temperature preceding milking accounted for 21.1% of the variation. Although earlier stages of lactation and larger daily milk yields were associated with higher prolactin concentrations, inclusion of lactation stage in the stepwise regression model tended to eliminate almost all the variance of prolactinpreviously associated with daily yield. Dominance measurements indicated that more submissive cows had higher milk prolactin. Individual cows tended to have characteristic prolactin, but this tendency was eliminated by statistical adjustment of the data for environmental and lactational variables.