Feed Barrier Research Articles

Feed barrier design affects behaviour and physiology in goats

Among other things, feed barrier design for goats can differ with regard to ease of leaving, backward view, and presence of physical separation. The aim of our study was to investigate whether the type of feed barrier influences agonistic behaviour and stress. The study involved 55 adult non-lactating female goats of several Swiss dairy breeds. Three groups of 14 and one group of 13 goats (2 horned, 2 hornless) were rotated between four pens with different types of feed barriers (neck rail, metal palisade, wooden palisade, diagonal fence). Each group stayed four weeks with each feed barrier type. Social interactions in the feeding area were recorded for 12 h per group and feed barrier type (1.5 h on 8 days each group) and corrected by the average number of feeding animals. Heart rate and heart rate variability were measured in lying and undisturbed goats to evaluate chronic stress independently of actual levels of motor activity and agonistic interactions. Individual faecal samples were taken for analysis of the concentration of cortisol metabolites. Data were analysed by linear mixed-effect models taking into account interactions between the type of feed barrier and presence of horns. Hornless goats displayed the most agonistic behaviour with physical contact in the feeding area of the neck rail and diagonal fence and least in the feeding area of the metal palisade, whereas goats with horns showed much fewer interactions of this behaviour; thus, only slight differences depending on the type of feed barrier were found ( p < 0.0001). Hornless goats also displayed the most agonistic behaviour leading to displacements from the feeding place with the neck rail, whereas for horned goats the effect of the type of feed barrier was less distinctive ( p = 0.0009). The duration of leaving the feed barrier was longest with the diagonal fence for both horned and hornless goats, while the horned goats also took longer to leave the neck rail compared to the palisades ( p = 0.0194). The interaction of type of feed barrier and presence of horns showed an effect on heart rate variability in the parameters root mean square of successive interbeat interval differences (RMSSD; p = 0.0355), RMSSD in relation to the standard deviation of all interbeat intervals (RMSSD/SDNN; p = 0.0215) and determinism ( p = 0.0364). The metal palisade distinctly differed from the diagonal fence as well as from the neck rail in hornless goats, with highest heart rate variability (HRV) and thus lowest levels of chronic stress in the pen with the metal palisade. Independently of horn status, the concentration of faecal cortisol metabolites tended to be lowest for goats in the pen with the metal palisade ( p = 0.0600). In summary, the metal palisade showed the most beneficial effects, especially on hornless goats. In contrast to the neck rail and the diagonal fence, both types of palisades seem to be recommendable for feeding goats in loose housing.

Introducing heifers to freestall housing

Little work to date has assessed how dairy cattle respond when first introduced to freestall housing. In this study we carried out 2 experiments. The aim of experiment 1 was to assess the behavioral responses of naïve heifers to pens fitted with freestalls. Holstein heifers (n=7 groups, each containing 3 heifers, 3 mo of age), with no previous experience with freestalls, were initially housed on a sawdust bedded pack and fed through a fixed feed barrier for at least 6 wk and then moved to a freestall pen fitted with a head-locking feed barrier. When kept on the bedded pack, the heifers’ lying time averaged 14.2 h/d. On the day heifers were moved to the freestall pen, lying times declined by 2.9h, but recovered on the following days. The time spent lying down on the barn floor (i.e., outside the lying area) increased by 2.5h on the day heifers were introduced to freestalls and remained higher during subsequent days. Heifers spent 46 min/d less time feeding on the day they were switched to the head-locking barrier, but recovered on the following days. In experiment 2 we assessed the behavioral responses of naïve heifers introduced to pens fitted with freestalls with or without a neck rail. Holstein heifers (n=12 groups, each containing 2 heifers, 3 mo of age), with no previous experience with freestalls, were initially housed on a sawdust bedded pack and then moved to a freestall pen with or without neck rails. Heifers spent 4.2 h/d less time lying down in the 24h following introduction into the freestall pen; the neck rail treatment had no effect on lying time but heifers spent more time standing with just their front 2 hooves in the stall when a neck rail was in the stall. In summary, lying and feeding behavior of naïve heifers is altered following introduction to new housing.

Effect of feed barrier design and feed space allowance on performance and behavioural parameters in dairy cows

Sixty mid-lactation Holstein–Friesian dairy cows (40 multiparous (cows) and 20 primiparous (heifers)) were allocated to one of four treatments in a 2 × 2 factorial design arrangement. The treatments involved two feed barrier space allowances (56 cm/animal (“high”) or 20 cm/animal (“low”)) and two feed barrier designs (‘open’ or ‘individual headspaces’). The ‘open’ barrier was a standard post and rail design, whereas ‘individual headspaces’ were created using vertical bars. Cows were housed in groups of 15 animals (10 cows and 5 heifers). A completely balanced changeover design was applied over four 5-week periods. Behavioural parameters were recorded during weeks 4 and 5 of each experimental period, while cow performance was recorded during Week 5. Behavioural scans were taken at 30 min intervals during two non-consecutive 24-h periods in each recording week. The total number of animals, and the proportion of these animals that were heifers, at the feed barrier and in the passageway behind the feed barrier were recorded. In addition, aggressive behaviour was recorded for 1 h after morning and evening milking on 1 day during each recording week. Due to technical difficulties, aggressive behaviour was not recorded in the ‘open barrier/high space allowance’ treatment. There was no significant effect of treatment on production performance parameters including dry matter intake (DMI) and average daily milk yield (average values: 21.7 and 32.0 kg/day, respectively). The average number of animals at the feed barrier increased as feed barrier space allowance increased (‘high’ 3.8, ‘low’ 2.8, SEM 0.08, F 1,9 78.3, P < 0.001), but was not significantly affected by barrier design. The proportion of animals at the feed barrier or in the feed passage that were heifers, and the total number of animals in the feed passage, was not significantly affected by treatment (average values: 0.34, 0.31, 0.55 animals, respectively). The total level of aggression was significantly higher in the ‘individual headspaces/low feed space allowance’ treatment than in the other two treatments (‘individual headspaces/low’ 1.07, ‘open/low’ 0.41, ‘individual headspaces/high’ 0.29, SEM 0.170 (interac./animal/10 min), F 2,15 12.04, P ≤ 0.001). It is suggested that it is more difficult to displace animals when individual headspaces are used, and that this exacerbates aggression in competitive situations. It is concluded that reducing feed barrier space allowance from 56 to 20 cm/animal does not adversely affect feed intake or milk yield levels in mid-lactation dairy cows when using either open barrier or individual headspace barriers. In addition, using individual feed spaces at low feed barrier space allocations appears to exacerbate aggression, which may have negative welfare implications.

Risk factors for skin lesions on the necks of Norwegian dairy cows

Physical restrictions at the feed barrier may cause skin lesions, especially on the necks of cows. Thus, some aspects of the functionality of feed barrier design can be assessed by observing skin lesions on the necks of dairy cattle. In this study, 232 herds, mainly of the breed Norwegian Red (94%), were investigated between September 2006 and June 2007. The herds were categorized into 2 groups. One data set, based on 1,148 cows (115 herds), was from farms using feed barriers with post-and-rail designs (86 herds) and combinations of barriers (29 herds). The second data set, which included 1,168 cows (117 herds), was from farms using only vertical feed barriers such as tombstone, diagonal, and headlock. Skin lesions were observed on the necks of 21% of the 2,335 cows observed. Forty-two percent of cows had neck lesions in herds with post-and-rail barriers, whereas 4% of cows had neck lesions in herds with vertical barriers and 30% of cows had neck lesions in herds with a combination of both horizontal and vertical barriers. Alternating logistic regression was used to identify factors associated with skin lesions on the necks of cows. The estimates were transformed into odds ratios (OR). In herds in which post-and-rail design barriers were used, the following risk factors were associated with skin lesions: manger front lower than 63cm versus higher (OR=3.6), no feed stalls versus feed stalls (OR=10.9), mixed rations versus no mixed ration (OR=3.8), cows later than 30 DIM versus earlier (OR=1.9), cows with low milk production versus those producing 1,000kg higher (OR=1.4), feeding frequency of less than 3 times daily versus 3 and more times daily (OR=1.9), using only post-and-rail feed barriers (OR=1.8) versus using combinations, and farmer disagreement with the statement “animals experience physical pain as humans do” (OR=1.9) versus agreement. Diagonal barriers, categorized as vertical barriers, increased the association of skin lesions with increasing manger front heights. Feed barrier design was associated with skin lesions on the necks of cows, particularly for barriers of a post-and-rail design. To minimize the risk of neck lesions, the top rail height of post-and-rail barriers should be above 109cm, especially for cows taller than 126cm, and the manger front should not be lower than 63cm. Feed stalls, feeding frequency of 3 or more times daily, and the feeding of unmixed rations were also identified as preventive factors.

Competition, activity budget and feed intake of ewes when reducing the feeding space

Even if ruminants are fed roughage ad libitum, reducing the number of feeding places may have negative effects on both feed intake and behaviour. The aim of this experiment was to investigate effects of reduced feeding space on competition, activity budget and feed intake of ewes fed ad libitum on two types of roughages. A 3 × 2 factorial experiment was conducted with number of animals per feeding place (1:1, 2:1 or 3:1) and type of roughage (grass silage or hay) as main factors. A total of 48 pregnant, adult ewes of the Dala breed were randomly divided into eight groups of six animals; four of these groups were fed grass silage whereas the other four groups were fed hay. The ewes were video recorded for 24 h at the end of each experimental period, and the activities such as feeding, queuing and resting of each ewe were scored using 10-min instantaneous scan sampling. Displacements from the feed barrier were scored continuously for the first 10 min of every hour. Daily intake of silage was not affected by reducing the feeding space from 1:1 to 1:3, but for ewes fed on hay, the daily intake was significantly reduced by 6.8% ( P < 0.05). However, time spent eating hay was significantly longer than time spent eating silage ( P < 0.05). Irrespectively of type of roughage, time spent eating was significantly reduced ( P < 0.0001) whereas CV for eating was increased ( P < 0.05) when feeding space was reduced. Overall, the competition level was higher when the ewes were fed on hay than on silage (queuing: P < 0.01; displacements: P < 0.01). In the hay treatment, the time spent queuing increased from 0.3% in the 1:1 treatment to 5.3% in the 3:1 treatment, but this was not significant in the silage treatment ( P < 0.001). Number of displacements was low at one ewe per feeding place, but increased significantly when feeding space was reduced in the hay treatment ( P < 0.01). In conclusion, the ewes competed more for access to feed in the hay than in the silage treatment, and increased competition with reduced feeding space was only found when the ewes were fed on hay. Similar results were found concerning feed intake. Thus, the effects of reduced feeding space are likely to depend on the type of roughage used.

Feeding management and characteristics of rations for high-producing dairy cows in freestall herds

The objectives of this cross-sectional observational study were to 1) describe the feeding management and characteristics of rations for high-producing Holstein cows housed in freestall barns in Minnesota, 2) evaluate ration change over time, and 3) investigate herd-level risk factors for ration change. Each of 50 randomly selected freestall dairy herds was visited once during the study. Samples of TMR were collected from the high-production group feed bunk to represent the initial ration as delivered to the cows, 3 additional samples were collected every 2 to 3h after feed delivery, and the accumulated orts were cleaned out of the feed bunk. Feeding management practices and TMR formulation were also collected at the time of visit. Seventy percent of herds fed once daily, 22% fed twice daily, and 8% fed 3 times daily. Frequency of feed push-up was 5.4±2.3 times daily. Linear feed bunk space per cow was 0.45±0.11m. Sixty-two percent of the farms had 3-row pens and 38% had 2-row pens. Linear feed bunk space per cow was greater in 2-row pens (0.56 m/cow) than in 3-row pens (0.39 m/cow). Post and rail was the most common type of feed barrier; it was used by 60% of the herds. Headlocks were used by 28% of the herds, combination of post and rail with headlocks was used by 8%, and diagonal bars were used by 4%. Water trough linear space was 4.6±2.1 cm/cow. Estimated dry matter intake was 24.3 kg/cow per day. The forage content of the formulated ration was 52% of the ration DM, and corn silage was the most commonly used forage. The NDF content of the analyzed ration was greater than the NDF content of the formulated ration (30.6 and 29.8%, respectively). In contrast, the CP content was lower (17.5 and 17.9%, respectively). Some feeding management practices (e.g., feeding frequency) were associated with ration NDF content change over time. This association may be minimized by implementing ration and management changes.

Feeding, resting and social behaviour in ewes housed in two different group sizes

The aim of this experiment was to investigate the effects of increased group size on eating- and resting behaviour, aggression and feed intake in housed ewes. During an initial period of 14 days 36 adult (2–6 years old) ewes of the domestic Norwegian Dala breed were divided into four groups of 9. In the second period (14 days), these ewes were merged into one group of 36 ewes. This experiment was repeated with a second batch of ewes, but this time starting with a group of 36 individuals in the first period, then splitting them up into four groups of 9 ewes in the second period. From 24 h video recordings we scored activity behaviours using instantaneous sampling every 10 min. Aggressive interactions were continuously observed the first 10 min every hour during the 24 h (4 h in total). A mixed statistical procedure with group size, day, batch and the interactions between them were included as fixed effects, whereas individual and group were specified as random effects. Ewes in large groups (36) had a larger variation in lying time at day one ( P < 0.01), less synchronized lying ( P < 0.05) and eating behaviour ( P < 0.01), and spent less time queuing at the feed barrier ( P < 0.001) compared to in the small group size (9). There were no effects of group size on aggressive interactions or feed intake. In conclusion, a larger group size decreased synchrony in resting and feeding behaviour and reduced the time spent queuing in front of the feed barrier. It is possible that the aggression level in sheep is more sensitive to changes in space allowance than to changes in group size per se.

PRESIDENTIAL ADDRESS AN OPPORTUNITY LOST AND SORTING FACT FROM FICTION

At the conference in Taupo last year, I identified 12 critical issues confronting agriculture that needed to be managed so that we continue to earn a first world living as a nation from the produce off the land. This year I want to discuss two issues related to improving the effectiveness of grassland technologies that will assist in addressing several of the issues listed above: 1. The feed barrier challenge and options to address it, and 2. Marketing of grassland technologies for improved production and productivity.

Increased group size reduces conflicts and strengthens the preference for familiar group mates after regrouping of weaned dairy calves ( Bos taurus)

The objective of the present study was to investigate how group size and familiarity influence daily activity and social interactions in regrouped dairy calves. A total of 84 calves were divided into groups of 4, 8 and 16 animals, in which half of the calves in each group were unfamiliar with each other. Daily activity, incidences of social interactions and play behaviour were recorded on days 1, 3 and 11 after regrouping. Time spent feeding and resting were not significantly affected by group size, but calves in larger groups spent more time feeding ( P < 0.05) and lying ( P < 0.01) close to one another than calves in groups of four. Calves in groups of 16 were more active ( P < 0.05) and spent less time standing inactive ( P < 0.05) than calves in smaller groups. The number of displacements from the feed barrier was higher in groups of four than in larger groups ( P < 0.05), and more displacements were directed towards unfamiliar calves ( P < 0.01). However, the level of agonistic behaviours and the number of displacements from the resting area, occurrence of mounting, cross-sucking, social grooming and play behaviour was not affected by group size. Calves in groups of 16 were found laying close to familiar calves more frequently than to unfamiliar calves ( P < 0.01) and they directed more social grooming towards familiar calves ( P < 0.01). In conclusion, calves in larger groups are generally more active, displace other calves less frequently from the feed barrier, show increased proximity to other calves and perform more positive social interactions with familiar calves the first 1–3 days after regrouping.

Herd-Level Risk Factors for Lameness in High-Producing Holstein Cows Housed in Freestall Barns

The objective of this study was to investigate the association of some herd-level factors with the prevalence of lameness in 53 high-production groups of Holstein cows housed on 50 commercial dairy farms having freestall barns in Minnesota. Cows in the high-production group (n=5,626) were scored for locomotion (score of 1 to 5, where 1=normal and 5=severely lame) to estimate prevalence of lameness (locomotion score ≥3) in the group. Herd-level variables were used to explain the variation in prevalence among groups. Among the variables tested, herd size, pen space per cow, type and size of milking parlor, total mixed ration content of crude protein and neutral detergent fiber, feeding frequency, linear feedbunk space per cow, type of feed barrier, and use of footbath did not show any association with the prevalence of lameness in the univariate analysis screening test and were not included in the multivariate model. Pen stocking density (cows per 100 stalls), total daily distance between pen and milking parlor, number of cows per full-time employee equivalent, cud chewing index, and pen type were eliminated from the multivariate model in the backwards stepwise procedure. Daily time away from the pen for milking was positively associated with the prevalence of lameness, whereas cow comfort quotient was negatively associated with prevalence of lameness. Prevalence of lameness was greater when farms performed hoof trimming only when the manager decided cows needed it because of hoof overgrowth or lameness compared with farms on which the feet of all cows were trimmed on a maintenance schedule once or twice annually. Brisket board height of more than 15.24cm and presence of the area behind the brisket board filled with concrete were associated with greater prevalence of lameness. Most of these herd-level factors could be managed to reduce lameness prevalence in commercial dairy farms.

Feed intake and social interactions in dairy goats—The effects of feeding space and type of roughage

The aim of this experiment was to examine how an increased number of animals per feeding place and type of roughage affected feeding time, feed intake and the level of aggressive competition in groups of dairy goats. We conducted a 3 × 2 factorial experiment with type of roughage (hay or grass silage) and number of goats per feeding place (1, 2 or 3) as the main factors. A total of 48 female goats in mid lactation was randomly divided into eight groups of six animals (mean age 3.7 years). The goats were video recorded for 24 h at the end of each experimental period, and activity variables such as feeding, queuing, standing/walking and lying were scored using instantaneous sampling with 10 min intervals. All incidents of social interactions were scored continuously for 6 h between 09:00 and 15:00 h. Individual goats from each group were ranked as high, medium or low according to the number of times they were displaced (physically or passively) from the feed barrier by another goat. Percentage of total observations spent feeding decreased ( P < 0.0001) and % of total observations spent queuing ( P < 0.0001) increased with increasing number of goats per feeding place. Silage intake also decreased with 16.2% from one to three goats per feeding place ( P < 0.001), but no such effect was found on hay. The reduced feeding space resulted in more than 80% reduction in feeding time for some individuals. The number of displacements at the feed barrier ( P < 0.05) and aggressive interactions ( P < 0.05) increased with an increasing number of goats per feeding place, and the aggression level was higher when offered hay than silage ( P < 0.0001). Low ranked goats spent significantly less % of total observations feeding ( P < 0.01) and more % of total observations queuing ( P < 0.05) than goats in medium and high rank categories, and this effect became more pronounced as the number of goats per feeding place increased. In conclusion, an increased number of goats per feeding place resulted in a lower % of feeding observations, a larger % of total observations spent queuing, and an increased number of aggressive interactions for both types of roughages. The level of aggressive competition was higher on hay than silage, suggesting a preference for hay. Although the actual feed intake of hay was not reduced by restricting the feeding space as opposed to silage, the dramatic reduction in % of total observations spent feeding for some individuals suggests that more than one goat per feeding place can not be recommended.

Ocular complications of barren brome exposure in a suckler herd

THE presence of a foreign body trapped between the palpebral conjunctiva and the cornea, in folds of palpebral conjunctiva, or above or below the nictitating membrane is an infrequent cause of ocular disease in cattle. Rebuhn (1995) suggested that plant material is the most common cause found in animals transported in open trailers or kept in windy areas, leading to epiphora, blepharospasm, conjunctival hyperaemia, chemosis and eventually corneal ulceration. Single cases involving plant material (Schecter and others 1985) and the presence of Thelazia species parasites in many animals have been reported in the UK (Arbuckle and Khalil 1976, 1978). This short communication describes an outbreak of conjunctival foreign bodies in a suckler herd caused by the seed of the herbaceous weed barren brome (Anisantha sterilis) also called sterile brome, drake or haver-grass (Fig 1), present in large-bale haylage. The affected farm was an organic mixed beef, sheep, arable and poultry enterprise in Somerset. The beef herd comprised 49, mainly pedigree, south Devon spring-calving suckler cows, two bulls and 78 youngstock of various ages. Winter feeding was predominantly grass silage, but some hay and haylage was also fed. Starting in late January 2005, haylage was fed off the floor behind a feed barrier to all stock. In early February, several of the cows and youngstock were noted to have ocular discharge and signs of discomfort. Of these animals, 10 were separated and submitted for veterinary examination. Presenting clinical signs included blepharospasm, epiphora, chemosis and conjunctival hyperaemia. Foreign bodies consisting of barren brome florets (reproductive units composed of a small flower/seed encased in longer fibrous sheath [Hubbard 1968] Fig 1b) were discovered embedded in the conjunctiva at various sites around the eye (Fig 2). Varying degrees of corneal ulceration were present in most cases. Foreign bodies were removed under topical local anaesthesia (amethocaine hydrochloride 1 per cent; Minims Amethocaine; Chauvin) using fine artery forceps, and oxytetracycline (Engemycin 5 per cent; Intervet) was administered subconjunctivally. The source of the problem was immediately identified by the herd owner, who was aware that barren brome was present in the haylage. Discarding the substantial quantity remaining was not considered commercially viable, and therefore presenting the haylage further back from the feed barrier (to prevent cattle burying their heads in the forage) was implemented immediately. Four days after the initial visit, further veterinary attention was requested. The whole herd was examined; a total of 19 animals was identified with signs of keratoconjunctivitis (17 unilaterally and two bilaterally). In 13 of these, florets were identified and removed, commonly from the lateral or medial canthi or under the nictitating membrane. In many affected eyes, multiple florets were present, and in one eye, four florets were found at various locations. Three animals also had signs of reflex anterior uveitis (episcleral congestion and miosis); these were treated with systemic meloxicam (Metacam; Boehringer Ingelheim). The incidence of disease in adult animals appeared substantially lower than in youngstock. Consequently, advice was given to feed the remaining haylage only to adults. Discarding the remainder of the haylage was still not considered practical. A third visit was made to re-examine the whole herd three days later. A total of 14 animals required treatment, of which three were repeat cases. Over the following six weeks, six cases were treated in the course of four visits. Resolution was uneventful in all cases. The case details are summarised in Table 1. The control of weeds on organic pasture has been a problem since the emergence of the organic movement (Bond and Grundy 2001). Control of barren brome relies predominantly on cutting fields before the brome goes to seed (Bond and Turner 2005). Other control measures include deep cultivation (Froud-Williams and others 1984) and reseeding. In this case, barren brome had previously been seen in arable crops and on pasture on the farm; however, because the farm was organic, there was no way of removing the brome from the fields during that season because the use of herbicides was restricted. Where barren brome had been present in previous years, the fields were mown early before the brome had seeded. Unfortunately, a period of wet weather just before the fields were due to be cut in 2004 meant that grass was cut much later than originally planned. As a result large numbers of barren brome seed heads were included in the haylage. The outbreak of conjunctival foreign bodies that occurred as a consequence lasted a number of weeks and had significant costs in terms of veterinary fees, stockman time, drug costs and possibly reduced weight gains. Unfortunately, discarding the haylage and purchasing additional organic forage was not considered economically or practically viable. Veterinary Record (2006) 159, 388-389

Stocking Density and Feed Barrier Design Affect the Feeding and Social Behavior of Dairy Cattle

The objectives of this study were to: 1) evaluate how stocking density at the feed bunk affects feeding and social behavior of dairy cows; and 2) determine if this effect is further influenced by the type of feed barrier used. Thirty-six lactating Holstein cows, allotted to 4 groups, were subjected to each of 4 stocking density treatments and 2 feed barrier treatments. Initially, 2 groups were assigned to a headlock barrier, and 2 groups to a post-and-rail barrier. Each group was then exposed to 4 stocking density treatments (0.81, 0.61, 0.41, and 0.21 m/cow, corresponding to 1.33, 1.00, 0.67, and 0.33 headlocks/cow), in 4 successive 10-d treatment periods. After these periods, the feed barriers were switched between groups and the 4 stocking density treatments were readministered. Time-lapse video was used to quantify feeding, standing, and aggressive behavior at the feed bunk. Daily feeding times were greater and duration of inactive standing in the feeding area was less when using a post-and-rail compared with a headlock feed barrier. Feeding time decreased and inactive standing increased for both barrier designs as stocking density increased at the feed bunk. Cows were displaced more often from the feeding area when the stocking density was increased, and this effect was greater for cows using the post-and-rail feed barrier. Cows ranked lower in the social hierarchy at the feed bunk were displaced more often when feeding at a post-and-rail barrier, particularly at high stocking densities. Therefore, we recommend avoiding overstocking at the feed bunk to increase feeding activity and reduce competition. Use of a barrier that provides some physical separation between adjacent cows, such as a headlock feed barrier, can be used to further reduce competition at the feed bunk.

Short Communication: Effect of Feed Barrier Design on the Behavior of Loose-Housed Lactating Dairy Cows

The objective of this study was to evaluate the effects of 2 feed barrier systems on feeding and social behavior of dairy cows. Forty-eight lactating Holstein cows were subjected to each of 2 treatments in a cross-over design. The treatments were 2 types of feed-line barriers: 1) post-and-rail, and 2) headlock. Time-lapse video was used to quantify the feeding behavior and incidence of aggressive displacements of the cows at the feed bunk. Average daily feeding time did not differ when cows used the headlock barrier compared with the post-and-rail barrier. However, there were certain changes in feeding time during periods of peak feeding activity: cows that had lower feeding times relative to group mates when using the post-and-rail barrier showed more similar feeding times to group mates when using the headlock barrier. There were 21% fewer displacements at the feed bunk when cows accessed feed by the headlock barrier compared with the post-and-rail barrier. These results suggest that using a headlock barrier reduces aggression at the feed bunk and improves access to feed for socially subordinate cows during peak feeding periods.

A comparison of space requirements of horned and hornless goats at the feed barrier and in the lying area

Loose housing of horned goats is more common than loose housing of horned cattle, and recommendations concerning the design of housing systems for horned goats are needed. In this study, we compared the behaviour of horned and hornless goats kept in deep litter pens to investigate their space requirements at the feed barrier and in the lying area. Two experiments were carried out with eight groups each of 10 females, four groups with and four groups without horns. In experiment 1, the number of feeding places (width 35 cm) was restricted stepwise from an initial 20 to 15 and 10. In experiment 2, the size of the lying area was stepwise reduced from 2.0 to 1.5 m 2 and 1.0 m 2 per animal. With each experimental condition, the behaviour of the goats was observed directly for 4 h a day during the feeding periods on 4 days (experiment 1) or by means of video for 24 h a day on 3 days (experiment 2). The average distance between the animals at the feed barrier was significantly lower in groups with horned goats (ANOVA with repeated measurements, P<0.05) and decreased significantly with decreasing number of feeding places available ( P<0.002), because low ranking animals had to share a feeding place. The proportion of time the animals spent feeding was also significantly lower in groups with horned goats ( P<0.02) and decreased significantly with increasing animal/feeding place ratio ( P<0.001). The average distance between lying animals was not significantly influenced neither by the presence of horns nor by the size of the lying area. On the other hand, the proportion of time the goats spent lying decreased significantly with decreasing space allowances ( P<0.05), but was not significantly influenced by the presence of horns. It is concluded that the space requirements of horned goats at the feed barrier are higher than those of hornless goats, whereas space requirements in the lying area do not differ between horned and hornless goats.

Feeding barriers to reduce damage by pine weevil (Hylobius abietis)

The effectiveness of feeding barriers to protect seedlings against damage caused by pine weevil (Hylobius abietis) was evaluated in experiments established from 1995 to 1999 in southern Sweden. For this purpose the damage done to containerized seedlings protected by various types of barrier was evaluated, and compared with damage to untreated and insecticide (permethrin)-treated seedlings. Three types of feeding barrier that gave significant protection during the first 3 yrs were recognized: coating on the stem bark, shields with a collar at the top, and shields without a collar. The mean accumulated mortality caused by pine weevil for coatings (47%) and shields without a collar (59%) was significantly higher than the corresponding figure for permethrin treatment (13%), whereas shields with a collar (26%) did not differ significantly from the permethrin treatment in this respect. The highest mortality was found for untreated controls (87%).

FORCE MEASUREMENTS IN WELFARE EVALUATION OF CATTLE HOUSING DESIGN

The force exerted on housing equipment by an animal may be used as a physical welfare parameter in the evaluation of housing design. This article is concerned with the force on a cow’s chest as she pushes against a self–locking feed barrier, as well as the force on the forelegs as she presses on the rear curb of the manger to reach her feed. The forces were determined in two experiments carried out with non–lactating cows of heavy breed. In the first experiment the force on the feed barrier was determined with the feed barrier placed either vertically or in a 20. inclined position combined with a manger width of either 1.20 or 0.62 m. The experiment showed that the force on the feed barrier remained low as long as the feed was kept within the cows’ reach in the narrow manger. With the wide manger, unacceptable forces were measured for both feed barrier positions. The inclined feed barrier allowed the cow to reach the feed at larger distances than the vertical feed barrier, however. In the second experiment the forces on both the feed barrier and the curb were determined for the same two feed barrier positions combined with a 135–, 200–, or 300–mm wide curb. Here a permanent manger width of 1.20 m was used. No serious forces were recorded on the curb in the case of inclined feed barrier as long as the curb width did not exceed 135 mm. For vertical feed barrier a curb width of up to 300 mm proved to be acceptable. For inclined feed barrier a curb width of 200 and especially 300 mm proved to be unacceptable. To avoid unacceptable forces on the cow’s chest a maximum manger width of 0.65 m is recommended for vertical feed barriers and 0.80 m for inclined feed barriers. To avoid unacceptable forces on the cows’ forelegs, a curb width of less than 200 mm is recommended for vertical feed barriers and 150 mm for inclined feed barriers.

Do Cows Prefer a Barn Compartment with a Grooved or Slotted Floor?

Cow preferences for one of two compartments with different floors were tested in a barn with two symmetrical, connected compartments, each intended for 16 cows. Compartments were identical except for the floor. One floor was grooved longitudinally to the feeding barrier and the other was slotted perpendicular to that barrier. Sixteen pregnant, lactating Holstein-Friesian cows were used. After 14 d of habituation, cow behavior was videotaped for 10 full 24-h d, spread over 22 d. Their daily time budget spent on different activities performed in both compartments was analyzed, as was their relocation and use of the concentrate dispenser in each compartment. On average, cows spent 120min longer per day in the slotted floor compartment than in the grooved floor compartment, and performed all activities in the daily time budget significantly longer in this compartment. However, testing the preference of individuals revealed that, although five cows significantly preferred the slotted floor compartment, two cows significantly preferred the other compartment, and nine cows had no preference. On the slotted floor, cows ate longer at the feeding barrier and more often drank front-on to the water trough; on the grooved floor they more often drank standing parallel to the water trough. Thus, they seemed to prefer to stand parallel to the slots. Relocation of cows, indicated by index of movement, was not significantly different between the floors. Relocation seemed to be stimulated more by the presence of concentrate dispensers in both compartments than by floor profile. Although one floor type was not clearly preferred over the other, the findings and methods of this study have implications for design and implementation of future preference tests for testing husbandry systems and their components.

Experimental Attempts to Reduce Predation by Harbor Seals on Out-Migrating Juvenile Salmonids

Abstract During spring, harbor seals Phoca vitulina feed at night under two bridges spanning the Puntledge River in Courtenay, British Columbia, Canada. Positioned parallel to one another, ventral side up, the seals form a feeding line across the river to intercept thousands of out-migrating salmonid smolts. During a 4-week observation period in the spring of 1996, we attempted to disrupt the seals' feeding patterns by (a) deploying a mechanical feeding barrier (cork line), (b) altering the lighting conditions (lights on a bridge were turned off), and (c) installing an acoustic harassment device. We found acoustic harassment to be the most effective feeding deterrent. Of the other two deterrents, turning off the bridge lights was more effective than deploying a cork line, which had little effect. Acoustic harassment devices appear to be the most effective, nonlethal means for protecting juvenile salmonids from harbor seal predation in portions of the Puntledge River.

The effect of irregular feeding times on the behaviour and growth of dairy calves

The objective of this study was to examine the effects of predictable vs. unpredictable management routines on the behaviour, production and health of dairy calves. Three different feeding schedules for milk-fed dairy calves were compared. All calves received milk twice a day, and had free access to concentrate, hay and water. Three groups of 12 calves (divided on two trials) were exposed to one of the following treatments from the age of 5 days to 9 weeks: group C (control) received milk at the same time every day, at 0700 and 1400. Group OD (occasional deviation) received the milk at the same time every day except on treatment days, one in week 5 and one in week 8, where they were fed 3 h later. Group IR (irregular schedule) received milk at irregular times throughout the experimental period. The first daily feeding took place between 0600 and 1300 and the second one between 1300 and 2100. When the calves were 5 and 8 weeks old, the behaviour of eight calves from each group was videorecorded for two days (48 h). The following behaviour was recorded: frequency and duration of lying bouts and frequency of comfort behaviour (defined as licking or scratching own body), eating, drinking, other oral behaviour and extending the head through the feeding barrier (HTB). The milk and concentrate consumption of the calves was measured and the calves were weighed weekly. Diseases were recorded. The results showed that at the age of 5 weeks, the calves in group IR differed from the control group C by performing more eating behaviour both on the control day (27.5 vs. 15.5; p<0.05) and the treatment day (28.8 vs. 18.3; p<0.05). At the age of 8 weeks, no differences were found in the behaviour between groups IR and C. When the OD calves were 5 weeks old, they responded to the delayed feeding by increasing drinking behaviour (14.5 vs. 9.0; p<0.05). When they were 8 weeks old, they showed increased frequency of comfort (195 vs. 122; p<.05), eating (37.5 vs. 27.9; p<0.05) and HTB behaviour (19.8 vs. 7.4; p<0.001) on the treatment day compared to the control day. The IR group did not respond to the same treatment except for a slight increase in drinking behaviour (9.6 vs. 6.5; p<0.05) at the age of 8 weeks. No differences were observed in the frequency or length of lying bouts, nor health or production parameters between the three groups. It is concluded that a predictable feeding schedule may not be very important for milk-fed dairy calves. However, when the calves are customised to predictable feeding times, occasional deviations from that schedule may cause frustration when their expectations are not fulfilled.