Freeze Branding Research Articles

Physiological and behavioral response of foals to hot iron or freeze branding

Branding horses with permanent marks is still a routine for many breeders in many parts of the world. This method of identification is traditionally done with a hot iron, although cold or freeze branding with liquid nitrogen has been widely disseminated as a less painful method. However, there are no studies comparing freeze and hot iron branding related to horses. This study aimed to compare brand quality and autonomic responses (heart rate variability), cortisol levels, and behavioral responses induced by hot branding (hot iron) and freeze branding (liquid nitrogen). Twenty-three foals of pure and crossbreds of Mangalarga Marchador, aged between 20 and 28 weeks, males and females were branded with the symbol 47 (6.5 × 8.5 cm) on the left shoulder. The animals were divided into 2 groups: hot iron (n = 11) and freeze (n = 12) and the twitching lip method was used to restrain the animals during the branding. No differences in cortisol levels were detected between the 2 groups. In the behavioral assessment, only in the hot iron group was one case of kicking and another of rearing observed. Horses in the hot iron group had more limb movements than did those in the freeze group. Our results have shown that hot iron branding has higher autonomic activation than freeze branding, with sympathetic predominance over the parasympathetic activation, as characterized by higher LF/ HF ratio, LF, SDNN/RMSSD ratio, and lower HF. Freeze branding produced fewer wounds and necrosis in the skin with no significant differences in the sharpness of the mark. Freeze branding proved to be a better option than hot iron because it causes less intense autonomic stress responses and fewer open wounds while giving the same sharpness as the hot iron branding. In terms of animal welfare, hot iron branding should be avoided or universally banned.

Survey of cow-calf producer perspectives on management strategies and industry challenges. Part 1: handling practices, and health and industry challenges.

The objectives of this study were to benchmark cow-calf producer perspectives on management strategies and challenges, and to determine if demographic differences and Beef Quality Assurance (BQA) certification status influenced the frequency of certain management strategies. A total of 1,414 responses from cow-calf producers in 44 states were collected through an online survey conducted in partnership with BEEF, a producer-focused magazine. Survey recipients were asked 30 questions to gather demographic information, respondents’ current handling and health management practices, and how they prioritized industry challenges. The frequency of management methods and decisions such as preconditioning and identification methods were impacted by respondent age, operation size, location, and BQA certification (Ps ≤ 0.009). BQA-certified respondents more frequently used electronic ear tags and freeze branding (Ps = 0.009). Overall, 74.5% of respondents were preconditioning their calves. Respondents who were BQA certified more frequently preconditioned their calves (449; 81.5%) compared with those who were not BQA certified (582; 70.4%) (P < 0.001). BQA training seems to be having a positive impact on production practices. Respondents identified cow-calf health as the biggest beef industry challenge and identified land availability or price as the biggest challenge to producers’ own operation. Respondents identified bovine respiratory disease, flies, pinkeye, and reproductive health as the most important animal health issues on producers’ operations. Health challenge responses varied significantly by producer age, beef cow inventory, and region of the United States (Ps < 0.001). Calf or neonate health was most commonly identified as the biggest challenge for respondents under the age of 30 years. Producers between the ages of 55 and 70 years most commonly responded that the Veterinary Feed Directive or regulations were more of a challenge than other age groups. Respondents clearly identified managing herd health as a challenge throughout the survey. Respondents with similar herd health challenges were identified based on demographic categorization, such as age of respondent and region.

Review of priority welfare issues of commercially raised bison in North America

A review of the scientific literature on bison was carried out as part of the National Farm Animal Care Council´s (NFACC) process of updating Canada’s current Code of Practice for the Care and Handling of Farmed Bison. Four priority welfare issues were identified: the effect of seasonality on the nutritional requirements of bison; bison behaviour; euthanasia on-farm; and pain. Bison reduce their feed intake and activity during winter, sparing energy reserves during periods of cold temperatures and food scarcity. To promote consistent carcass quality in this highly seasonal animal, producers commonly feed bison high grain diets. It has been suggested that feeding bison high concentrate finishing diets, greater than 80%, over a significant period of time, is likely to cause ruminal acidosis. Research is required into strategies that could help producers manage the effects of seasonality and to make it work to their advantage. When bison are unable to compensate for nutritional seasonality in summer it can lead to reduced herd fertility from poor nutrition and reduced body condition. Regarding behaviour, the handling of bison differs from traditional cattle handling techniques, as they do not move the same way through handling facilities. Injuries and death during handling are more likely to occur if bison are handled incorrectly. They are more excitable than cattle, which have been bred for calm temperaments. Bison have a very intact social structure that has definite spacing requirements. The flight zone of bison tends to be much greater than that of cattle, and bison can be moved most effectively if the handlers work on the edge of it. Bison that become severely stressed during handling can suffer from a recognized condition known as capture myopathy. Handling facilities should restrict bison’s vision and minimize loud noises. Bison should never be left in isolation as solitary bison display high levels of agitation. In the event of euthanizing bison on-farm, specific information regarding the gauge, calibre of firearm, and bullet selection is lacking. However, the combination of firearm and ammunition selected must achieve a muzzle energy of at least 1000 ft-lb (1356 J) for animals larger than 400lbs (181 kg). Understanding the correct landmarks for euthanizing bison are especially important as they are anatomically different from cattle. Due to the physical thickness of a bison skull, higher calibre firearms or heavier gauge shotguns are required than those used for other species. Bison producers in Canada rarely, castrate or brand animals, and they are seldom dehorned. There is currently a lack of peer reviewed research regarding the effect of painful procedures in bison, however, there is little reason to suspect their physiological responses to pain are different to cattle. Both freeze branding and hot-iron branding cause pain and distress in bison, however in cattle, freeze branding causes less acute pain at the time of the procedure which would likely be similar to bison.

Freeze Brand Retention in Channel Catfish and Channel Catfish × Blue Catfish Hybrids

AbstractWe evaluated freeze brands on Channel Catfish Ictalurus punctatus and hybrid catfish (female Channel Catfish × male Blue Catfish I. furcatus) to determine suitability of the technique for identification of year‐class on ictalurid catfishes. Freeze brands were applied to fish in a hatchery setting, and adipose fins were removed as a secondary mark. Marked fish were stocked into two Kansas reservoirs within 3 d after marking. Fish were sampled with a suite of gear types for 3 years after the initial stocking in 2013. All captured catfish were observed for the presence of a freeze brand and an adipose fin. A logistic regression model estimated 80% brand retention for Channel Catfish through 460 d. The logistic regression model for hybrid catfish brand retention as a function of days at large was not significant, but retention remained near 80% throughout the 3‐year study period. Results suggest that freeze brands are suitable for marking Channel Catfish and hybrid catfish in natural systems when marks should be retained for at least 1 year and up to 3 years.Received March 6, 2017; accepted September 14, 2017Published online October 30, 2017

Evaluation of Three External Marking Methods of Farmed Atlantic Salmon for the Future Use of Differentiating it From Wild Atlantic Salmon

We evaluated different external marking methods for farmed salmon to differentiate it from wild salmon without any special tools. Three marking methods were tested: 1) Adipose fin (AF) removal, 2) Freeze branding (FB) and, 3) Visible Implant Elastomer (VIE). Location of the marking method on the fish, combination of marking methods and degree of AF removal were tested in three experiments. Atlantic salmon parr weighing 20 g were marked either with individual marks or in combination of two. Further all the fish were also PIT tagged. They were kept in freshwater tanks for 4 months and later after smoltification, smolts were transferred to sea cages and kept for another 4 months. At the end of four (freshwater phase) and ten (sea cages) months, growth, survival and mark retention were recorded. All these methods had no significant effects on growth and survival compared to the control (no mark but only PIT tagged). Our results showed that of these methods, only complete removal of the adipose fin met the requirements for mark retention and was the cheapest and easiest method to automate. However, a larger commercial scale long-term testing of the AF clipping is required prior to implementing it. Further development of an automated fin clipping in combination with vaccination and an open discussion with consumers, buyers, and environmental groups are also warranted.

Artificial Marker Selection and Subsequent Tagging Evaluations with Juvenile Burbot

AbstractA conservation program developed by regional stakeholders incorporates stock enhancement as one of several approaches to restore an imperiled Burbot Lota lota population native to Idaho and British Columbia. Tagging juvenile fish is pivotal to stock enhancement monitoring; however, limited information is currently available on marks or tags applied to Burbot. We identified six criteria to guide artificial marker selection that are specific to imperiled juvenile fish. A short‐term experiment with age‐0 Burbot (65–92 mm TL) tested fin clips, freeze brands, visible implant elastomer, passive integrated transponders, and an unmarked control group. At 4 weeks posttagging, no significant differences were found between marking treatments with respect to fish survival (100%), absolute growth rate (0.15 ± 0.06 mm/d), specific growth rate (0.55 ± 0.32 g·g−1·d−1), or condition factor (0.64 ± 0.05). Mean tag retention ranged from 88% to 100%, and no significant differences were detected between treatments. Recognition of dorsal freeze brands differed significantly between two independent tag assessments. Overall, we found no adverse short‐term effects and high tag retention in this preliminary trial of seven artificial marks applied to hatchery‐reared Burbot.

Comparison of three methods for marking a small floodplain minnow

Evaluation of the movement patterns of small-bodied fish is often hindered by the lack of a suitable long-term mark. We evaluated several techniques for long-term group and individual identification of adult (40–70 mm total length [TL]) Oregon chub (Oregonichthys crameri). We marked Oregon chub with one of two different sized passive integrated transponder (PIT) tags (a 9 × 2.12 mm, 0.067 g PIT tag [PIT-tag] or a 8.4 × 1.4 mm, 0.033 g PIT tag [PICO-tag]), a red visible implant elastomer (VIE) tag, or a freeze brand. We monitored survival, tag retention, and mark quality over 150 days. In addition, we assessed the minimum length and weight thresholds to achieve 80% and 90% survival of PIT-tagged fish. Marking with a freeze brand, PICO-tag, or VIE tag had no effect on survival (P >0.05). In contrast, marking with a PIT-tag was associated with significantly lower (P <0.05) survival than in the control group. Survival was significantly higher (P = 0.002) for fish implanted with a PICO-tag than with the larger PIT-tag. The initial minimum TL for 80% and 90% survival was 54 mm and 64 mm TL, respectively, for the PIT-tag treatment. The 90% survival threshold for PICO-tagged fish was 44 mm TL. The 80% survival threshold was outside the range of sizes used in our experiment (<40 mm TL). Similarly, the 80% and 90% survival weight thresholds for the PIT-tag treatment were 1.5 g and 2.4 g, respectively, and the 90% survival threshold for PICO-tagged fish was 0.9 g. Tag retention was 94% and 95% in the PIT-tag and PICO-tag treatments, respectively; 80% of the freeze branded fish had easily recognizable tags after 150 days and 88% of the fish marked with VIE had easily recognizable tags after 150 days. PICO-tags, VIE marks, and freeze brands are all feasible long-term marking techniques for Oregon chub with negligible effects on survival through 150 days. The selection of a particular technique should be based on the study design and objectives (e.g., individual versus group identification), cost, ease, speed of tagging, and survival.

The effect of early handling of foals on their reaction to handling, humans and novelty, and the foal–mare relationship

The natural behaviour of horses in response to danger is to take flight, and consequently human handlers can be injured. Reducing the flight response and general reactivity of horses is therefore likely to reduce the incidence of injuries to handlers. In this experiment we investigated the effect of handling foals in the first 2 days after birth on their subsequent response to handling, humans and novelty, and the foal–mare relationship. Standardbred foals were assigned to one of two groups, handled (H) ( N = 22, 12 colts, 10 fillies) and control (C) ( N = 22, 11 colts, 11 fillies). Handling took place 3 times/day on days 1 and 2 after birth for 10 min/session. Individual foals were gently restrained and stroked all over their body using bare hands and then a plastic bag and each leg was lifted once. C foals received no handling. C and H foals did not differ in their reaction to freeze branding at a mean age of 14 days. The approach and leave behaviour of mare–foal pairs were observed at pasture during week 5 to evaluate their relationship. Mares of H foals were less active in keeping the pair together than mares of C foals (GLM: F 1,33 = 6.81; P < 0.05). At 6 weeks of age all colts were introduced to an arena, together with their mare, and their reaction to a novel object and an unknown human were tested. Treatment did not affect heart rate of foals or in mares. C foals initiated more suckling bouts than H when no human was present (Wilcoxon: Z = 2.44, N = 22, P < 0.05) indicating that they responded differently to the novel arena than H foals. However, there was no difference between H and C foals in their exploratory behaviour in the arena. When a human was present in the arena, H foals had a shorter flight distance than C foals ( Z = −1.98, N = 22, P < 0.05) and tended to move further away from the mare ( Z = −1.80, N = 22, P = 0.07). Handling of foals in the first 2 days after birth appeared to affect the foal–mare relationship and alter their perception of humans at a later age but did not alter their response to novelty or to handling. The effects of early handling of foals on the foal–mare relationship require further investigation.

Long-term examination of health conditions in monoculture of communally tested amphimictic diploid, diploid gynogenic and triploid tench, Tinca tinca (L.)

Amphimictic diploid (2n), induced triploid (3n) and meiotic gynogenic (MeiG) tench populations were established in 1998 by mass propagation. After separate nursing, fish were group-marked by freeze branding and 200 specimens per population were stocked into an experimental earthen pond for communal test until present. Parasitological and haematological (haemoglobin content Hb, haematocrit PCV and differential leukocyte count) examinations were performed every spring and autumn in the 2+ category, once sex could be registered macroscopically. Altogether 9 genera and/or species of parasites were detected on skin, 7 genera and/or species on gills, 1 genus in eye and 1 species in gut. The highest invasion extensity was recorded in the MeiG tench in the majority of examinations till the age of 4+. The courses of PCV and Hb values for 2n and MeiG populations showed high similarity while those for 3n population were slightly decreased and sex-related differences proved to be insignificant within populations in the majority of examinations. Differential leukocyte counts showed significant differences (p<0.05) of 3n vs. 2n and/or MeiG considering lower proportions of lymphocytes and higher proportions of segmented neutrophils in the majority of cases.

USE AND EFFECT OF FREEZE BRANDING ON ROACH (RUTILUS RUTILUS L.)

We tested the effects of freeze branding on growth, survival and mark retention in roach Rutilus rutilus L. (82-268 mm in total length). Markings were applied at two positions on the skin: (1) the depressed area above the anal fin, (2) the muscles above the lateral line and between the caudal and dorsal fins. A control group received no mark. The experiment duration was 30 days, and 120 roach were selected and distributed into three lots. Retention rates were high and ranged between 94% for position 2 and 100% for position 1. Survival rate after 1 month was 87% for freeze branded roach at position 2, 90% for position 1 and 92% for unmarked fish. These differences were not statistically significant. A significant decrease of linear growth was observed for individuals marked at position 2 (3.2 mm.month -1 ), but the implication of the brand itself was unclear. We discuss the short- and long-term properties of freeze branding techniques on roach.

Survival, Growth, and Mark Persistence in Juvenile Black Crappies Marked with Fin Clips, Freeze Brands, or Oxytetracycline

We tested the relative performance of fin clips, freeze brands, and oxytetracycline (OTC) marks on juvenile black crappies Pomoxis nigromaculatus. Fish held for 5 d after treatment in laboratory aquaria at 18, 21, 24, and 27°C showed no significant difference in survival (100% in most replicates). Continuing effects of the marks on growth and survival were tested by stocking juveniles with each mark and nonmarked fish into research ponds. No significant differences in survival, length, weight, or condition factor (K) were observed after 31 weeks. Freeze brands, fin clips, and OTC marks all proved to be effective for marking juvenile black crappies; however the fin clips and freeze brands persisted significantly better (P = 0.0007) than the OTC marks through 31 weeks.

Survival, Growth, and Abundance of Pellet-Reared and Minnow-Reared Muskellunge Stocked in Northwestern Iowa

Abstract Recent advances in artificial feeding techniques have increased the numbers and reliability of fingerling production of muskellunge Esox masquinongy in Iowa. Most of the muskellunge fingerlings produced in Iowa since 1984 were raised on dry pelleted feed. We compared the survival of pellet-reared fingerlings with traditional minnow-reared fingerlings stocked into Spirit and West Okoboji lakes in northwest Iowa. Beginning in 1991, all muskellunge fingerlings were marked with freeze brands to differentiate the type and year that fingerlings were stocked. Adult muskellunge were caught each spring with 360-ft, 2.5-in-bar-mesh gill nets. All muskellunge caught were examined for brands, individually marked with visual implant tags, and released into the same lake as captured. Abundance and survival of stocked fingerlings to year-classes were estimated from recaptures of branded and individually marked muskellunge. In most years none of the pellet-reared fingerlings survived. The poor survival of these ...

Evaluation of Razorback Sucker and Colorado Squawfish Batch Marking Techniques

Abstract Young razorback sucker Xyrauchen texanus (mean total length [TL] = 127 mm) and Colorado squawfish Ptychocheilus lucius (mean TL = 150 mm) were marked by freeze branding and injection of a fluorescent elastomer. The elastomer injection was made at the base of the anal fin and on the operculum (razorback suckers) or lower jaw (Colorado squawfish) and consisted of one of four colors: green, blue, red, or orange. Freeze branding had 99% retention after 15 months for both species. Elastomer recognition was better for Colorado squawfish (mean 74%) than for razorback suckers (mean 60%) after 15 months, and retention at both locations was similar. Red and orange had the best recognition and blue had the poorest. Red and orange elastomer injected in young Colorado squawfish could be detected (95%) for 5 months. One person implanting elastomer at two locations on each fish and one person anesthetizing and handling fish can mark 130–140 fish/h. Approximately three times that number can be freeze-branded per...

Marine reserves: patterns of adult movement of the coral trout (Plectropomus leopardus (Serranidae))

Movements of Plectropomus leopardus (Serranidae), a major fisheries species, across marine reserve boundaries were investigated on the Great Barrier Reef, Australia. Mark-release-recapture and ultrasonic telemetry were used to assess movements. Mark-release-recapture used hook and line as the method of capture and underwater visual census (UVC) as the "recapture" tool. Catch rates were significantly higher in zones closed to fishing, despite UVC indicating no significant differences in density between closed and open zones. Of 183 fish marked with numerical freeze brands, 93 estimates of movements of branded fish were obtained. No branded fish was recorded to cross the reserve boundaries during the 2-month study, probably due to the initial decision to allocate capture effort evenly across the study area, rather than concentrating it on reserve boundaries. Fish carrying ultrasonic transmitters, and having home ranges straddling reserve boundaries, crossed boundaries on average 15.3 times ·month-1. The mean distance moved by freeze branded specimens between capture and recapture was significantly larger in areas closed to fishing than in those open to fishing. However, mean distance moved per day determined by ultrasonic telemetry did not differ between areas closed and open to fishing. This study suggests low flux rates of adult P. leopardus across marine reserve boundaries.

The use of infrared thermography to assess inflammation associated with hot-iron and freeze branding in cattle

Infrared thermography was used to compare differences in extent and duration of inflammation observed on hot-iron and freeze brand sites as an indicator of tissue damage and the associated discomfort to the animals. Thirty beef heifers of mixed breed were assigned to either hot-iron (H) or freeze (F) branding treatments according to a predetermined randomized branding order. Ten animals were branded each day over a 3-d period. On the day prior to branding, animals were clipped to expose two patches of skin; one to be used for the branding treatment and the other for a control. Thermographic images of control and treatment sites were made at 0.08 h (5 min) prior to branding, immediately after the brand was completed (0 h), as well as 0.08, 2, 4, 8, 12, 24, 48, 72, 96, 120, 144 and 168 h after branding. Control site temperatures were subtracted from treatment site temperatures for each individual animal. Both F and H brand sites were consistently warmer (1.9 ± 0.3 and 1.6 ± 0.3 °C, respectively) than their corresponding control sites between 2 and 168 h after branding. Treatment differences were obtained at 0, 0.08, 2, 8, and 144 h after branding (P &lt; 0.001, 0.05, 0.005, 0.001, and 0.01, respectively). Freeze brand sites were warmer at 2 and 8 h after branding while H sites were warmer at 144 h after branding. The thermographic evaluation of hot-iron and freeze brand sites indicated that both methods caused tissue damage. However, H brand sites remained significantly warmer than F sites at 168 h after branding. In addition, H sites were significantly warmer than control sites while F sites were not warmer than control sites at 168 h. The prolonged inflammatory response observed in H animals indicates that more tissue damage and perhaps more discomfort are associated with H branding. Key words: Thermography, branding, cattle, animal welfare, pain.

Comparison of hot-iron and freeze branding on cortisol levels and pain sensitivity in beef cattle

Thirty yearling (450–500 kg) heifers of mixed breeds (Hereford, Charolais, Angus and Shorthorn) were habituated to handling over a 14 ± 2 d period before branding and were fitted non-surgically with jugular catheters 1 before branding. On the day of branding, heifers were assigned to hot-iron brand (H), freeze brand (F), or control (C) treatments according to a predetermined randomized branding order (n = 10 per treatment). Blood samples were obtained at 20 and 0 min before and 20, 40, 60, 80, 100, 120, 140, 160 and 180 min after application of branding treatments. To detect stress-induced analgesia, each animal's sensitivity to pain was assessed by measuring the time it took them to respond to a thermal energy source (laser) applied to their hind legs. Foot-lift latencies were obtained 0, 10, 20, 60 and 120 min after the treatments were imposed. Sensitivity to touch also was assessed 1 and 7 d after branding by placing pressure on the brand site and measuring the amount of movement by the animals. Both H and F heifers had higher mean plasma cortisol concentrations than C animals 20 and 40 min after branding (P &lt; 0.05). However, hot branding was found to cause a more pronounced cortisol response than freeze branding at 40 min (P &lt; 0.05). No treatment differences in foot-lift latencies or sensitivity to touch were observed. Both branding methods cause discomfort in cattle; however, hot branding appears to cause a greater acute response than freeze branding. Key words: Branding, cattle, cortisol, stress-induced analgesia

Effects of branding on weight gain, antibiotic treatment rates and subsequent handling ease in feedlot cattle

Two trials were conducted to investigate the effects of hot-iron and freeze branding on individual body weight (BW) antibiotic treatment (AT) rates based on rectal temperature (RT), and subsequent handling ease in feedlot cattle. Charolais-cross steer calves were ear-tagged and vaccinated on arrival to the feedlot and assigned to freeze brand (F), hot-iron brand (H), or control (C) treatments. Animals were branded at arrival to the feedlot in Trial 1 (n = 300) and 20 d after arrival in Trial 2 (n = 248). Rectal temperatures, AT and BW of all animals were recorded on the day of branding and every second day for 10 d. Branding treatments had no effect on average daily gain (ADG) or AT rates in either trial. Steers in Trial 2 required increased handling pressure over the 10 d period, indicating some aversion to being caught in the chute for measurement of RT. The only effect of treatment on handling ease was that freeze branded steers required more (P &lt; 0.005) handling pressure than C or H steers on d 6 after branding. This may have resulted from discomfort caused by pressure put on the freeze branding site while in the chute, perhaps indicating that F animals may experience a lingering pain. Branding, regardless of technique, does not affect BW or AT rates when performed soon after arrival or following a 20 d acclimation period in the feedlot. These findings suggest that branding may not be a severe enough stressor to negatively affect BW gain or health in cattle. There may be some potential in using handling ease as an indicator of an animal's aversion to re-enter the location of a previously negative experience. Key words: Cattle, Branding, Behaviour, Liveweight Gain, Body Temperature

Behavior of cattle during hot-iron and freeze branding and the effects on subsequent handling ease.

Three hundred feedlot steers (320 +/- 2 kg) were assigned to freeze brand, hot-iron brand, and sham branding treatments according to a randomized branding arrangement. Behaviors believed to be indicative of pain (i.e., tail-flicking, kicking, falling, and vocalizing) were recorded during branding. Escape behavior, measured as the amount and duration of force exerted on the headgate and squeeze chute by the animals during treatment, was obtained using load cells and strain gauges. Subsequent handling ease following branding was tested every 2nd d for 10 d by recording the time and effort required to move animals into the chute. Hot-iron-branded steers had greater tail-flick, kick, fall and vocalization frequencies than freeze-branded or sham-branded animals (P < .005). However, freeze-branded animals differed from shams only in regard to tail-flick frequencies (P < .005). The average and maximum exertion forces and the duration of force were greater in hot-iron-than in freeze- and sham-branded steers (P < .001); freeze branded steers had greater values than shams (P < .001). No treatment differences in handling ease were observed. However, all steers required more handling effort for up to 6 d, indicating that handling, per se, was aversive. Results indicate that hot-iron-branded steers experienced more discomfort at the time of branding than freeze-branded and sham steers, and freeze-branded steers experienced more discomfort than shams.

Skin Reflectance as a Nonlethal Measure of Smoltification for Juvenile Salmonids

Our efforts to find nonlethal methods of assessing the parr-smolt transformation of juvenile steelhead Oncorhynchus mykiss and spring and fall chinook salmon O. tshawytscha led to the development of a video system for quantitatively measuring skin silvering using skin reflectance. Gill Na+, K+-ATPase activity, skin guanine concentration, and skin reflectance were recorded from groups of fish marked with freeze brands at hatcheries and downstream sample sites in the Columbia River basin. Skin reflectance of migrants was significantly higher than that of fish before release; nonmigrants (released fish that did not migrate) had significantly lower skin reflectance than migrants from the same groups. Skin reflectance was significantly correlated with gill ATPase activity and skin guanine concentration. Skin reflectance increased during the parr–smolt transformation and could be used as a nonlethal indicator of smoltification.

Evaluation of a commercial stencil/aerosol — Coolant technique for freeze branding horses

SUMMARY A study was conducted to evaluate a commercial stencil/aerosol-coolant freeze branding technique for horses. Forty five (45) mares were branded with one of five treatments to determine which combination of pre-treatment application of alcohol on the brand site, number of coolant spray applications or drying methods produced the most acceptable brands. Reactions indicative of pain were quantitated for all treatments. Kit equipment and recommended procedures were evaluated. Non-alcohol pre-treated digits tended to be more acceptable than alcohol pretreated digits (P .20), number of applications (P >.10) or drying method (P >.12). The stencil/aerosol-coolant technique is safe and convenient, but at least three applications of spray are necessary to produce acceptable brands.