Occurrence of Blood Cells and Serum Proteins in Bovine Fetuses and Calves

Hematological values of peripheral blood were determined for bovine fetuses and calves of various ages. Erythrocyte values increased through gestation. Fetuses 100 days or older had total values within the ranges of those reported for normal adult cattle. Mature erythrocytes were not observed in embryos and only a few were observed in fetuses 40 days of age. Fetuses 250 days or older had only a few rubricytes (<10/100 WBC). Leukocytes were first identified in the peripheral blood of a 45-day old fetus. Absolute leukocyte values increased through gestation and reached maximum values shortly before parturition. Granulocytes were first observed at 130 days of gestation and reached maximum values near parturition.

Total serum protein and gamma-globulin concentrations of colostrum-deprived calves were similar to serum protein and gammaglobulin concentrations of fetuses older than 265 days and were lower than values for the colostrum-fed calves. The immunoelectrophoretic pattern of 59-day old fetuses, the earliest age at which serum samples were obtained, demonstrated albumin, an α1 globulin and a β globulin, possibly transferrin. Additional α and β globulins appeared in the older fetuses and by 175 days of gestation serum electophoretic patterns of the fetuses were similar to patterns normally found with adult bovine serum except for the absence of the gammaglobulins in fetal serum. Immunoglobulin M was detected in 39 of 95 fetal serum samples by radial diffusion and in 13 of 95 samples by immunoelectrophoresis. Immunoglobulin G was detected in ten of 95 fetal serum samples by radial diffusion and in six of 95 samples by immunoelectrophoresis.

     

Studies on Diarrhea in Neonatal Calves: The Plasma Proteins of Normal and Diarrheic Calves During the First Ten Days of Age

The concentration of serum proteins and plasma fibrinogen were determined in 151 normal and 49 diarrheic calves at intervals from birth to ten days of age. There were significant differences in the concentrations of the various serum proteins in normal calves when the results were analysed at six age intervals. There was no significant relationship between the concentration of the various proteins and the season of the year.

Of the diarrheic calves, those that died had significantly lower gamma globulin concentrations than the other calves. Severely diarrheic and dehydrated calves had significantly increased serum albumin and alpha glabulin concentrations and decreased gamma globulin concentrations. No significant variation occurred in total serum protein concentration. Plasma fibrinogen concentrations were similar in normal and diarrheic calves.

     

Severity and nature of acidosis in diarrheic calves over and under one week of age

A prospective study of the severity of dehydration and acidosis was carried out in 42 calves under 35 days of age presented for treatment of neonatal diarrhea. Clinically the mean level of dehydration was 8 to 10%. The plasma volume was 65% of that in the hydrated calf but the calves only gained 6.5% in weight during therapy.

Calves under eight days of age often had a lactic acidosis. Blood pH was 7.118±0.026 (mean ± 1 standard error), bicarbonate concentration 18.8±1.3 mmol/L, base deficit 11.4±1.7 mmol/L and lactate of 3.6± 0.06 mmol/L. Calves over eight days usually had a nonlactic acidosis. Blood pH was 7.042±0.021, bicarbonate 10.8±1.0 mmol/L, base deficit 19.5±1.2 mmol/L and lactate 1.2±0.3 mmol/L. These values were all significantly different from those in younger calves.

Over all calves there was a poor correlation between the severity of acidosis and dehydration(r=0.05). The severity of lactic acidosis was related to the severity of dehydration. Mean bicarbonate requirements to correct acidosis were calculated to be 200 mmol(17 g of sodium bicarbonate)and 450 mmol(37 g of sodium bicarbonate)in calves under and over eight days of age respectively. Both groups of calves required a mean volume of 4L of fluid to correct dehydration.

     

Studies of Enteric Pathogens and γ-Globulin Levels of Neonatal Calves in Sweden

Viring, S., S.-O. Olsson, S. Alenius, U. Emanuelsson, S.-O. Jacobsson, B. Larsson, N. Linde and A. Uggla: Studies of enteric pathogens and γ-globulin levels of neonatal calves in Sweden. Acta vet. scand. 1993, 34, 271-279.– Faecal and blood samples were taken from 10-30% of calves, 36 hours to 14 days old, in 47 dairy herds in different regions of Sweden from September 1987 to October 1988 (Olsson et al 1993). Faecal samples from 279 calves were analysed for the presence of Escherichia coli (K99⁺), rotavirus and Cryptosporidium sp. Twenty (7.2%) of these samples were from diarrhoeic calves. An ELISA was developed and used for the rotavirus analysis. E. coli K99⁺ was detected in 11.5%, Cryptosporidium sp. in 6.1% and rotavirus in 5.4% of the faecal samples. The presence of rotavirus alone and the combination rotavirus and E. coli (K99⁺) was found to be associated with diarrhoea (p<0.001 and p<0.01 respectively).Blood samples from 327 calves were analysed for the level of total protein and γ-globulin. In 43 of these samples (13%) γ-globulin did not separate from the ß₂-region by electrophoresis. The mean total protein concentration was 53.6 g/1 in calves free from diarrhoea. The mean γ-globulin concentration, adjusted to 7 days age was 5.9 g/1. The 20 diarrhoeic calves had lower levels of both total protein and γ-globulin, compared with calves without diarrhoea, but the difference was not significant. One litre more of colostrum at the first feed increased the level of total protein of the calves’ sera by 1.4 g/1 (p = 0.05). Calves born between May and September had a 2.0 g/1 higher (p<0.001) serum concentration of γ-globulin than calves born between October and April.     

Morphometric Parameters of Peripheral Nerves in Calves Correlated with Conduction Velocity

Background

Peripheral nerve injuries are the most frequent neurologic disorder in cattle. So far, no physiologic values have been established for the motor nerve conduction velocity (mNCV) in this precocial species.

Objectives

The electrophysiologic and morphometric reference values of peripheral nerves in calves were determined. It was hypothesized that these parameters would correlate to the high degree of maturity in the first days of life in this species compared to other species.

Animals

Twenty‐six healthy calves were used in this study.

Methods

The mNCV of the radial and the sciatic/common peroneal nerve was measured in all 26 calves. Nerve biopsies from a group of 6 calves were taken to correlate the obtained electrophysiologic data with morphological parameters.

Results

The mean mNCV of the radial nerve was 48.3 ± 10.6 m/s, whereas the mean mNCV of the sciatic/peroneal nerve was with 83.8 ± 5.9 m/s significantly faster (P < .0001). The average fiber diameter was 8.40 ± 2.80 μm (range, 1.98–17.90 μm) and the average g‐ratio was 0.61 ± 0.04 SD.

Conclusion and Clinical Importance

The established reference values for mNCV in calves correlate well with the evaluated morphometric parameters. Attributable to their comparably fast mNCV and high fiber diameters, juvenile calves appear to be much more mature individuals than other mammals. Electrophysiologic characterization of peripheral nerve injury now is feasible in this species.     

Cholinesterase Levels in Blood Plasma and Erythrocytes from Calves,Normal Delivering Cows and Cows Suffering from Parturient Paresis

Plasma cholinesterase (pChE) levels and erythrocyte acetylcholinesterase (eAChE) levels were studied in 6 cows before, during and after parturition (Group I), their calves (Group II), 38 cows suffering from parturient paresis (Group III) and 14 newly delivered non-paretic cows (Group IV).The mean of the pChE level in Group I was 1.5 μkat/1 ± 0.20 before parturition and decreased significantly (P ≦ 0.05) to 1.2 ukat/1 ± 0.16 after parturition. The eAChE level was before parturition ≅ 140 ukat/1 and decreased to ≅ 130 μkat/1 4–5 weeks after parturition.At birth the pChE level was 12.8 ukat/1 ± 5.9 in Group II. After 4 weeks the level had decreased to 2.3 ukat/1 ±0.3. In the bull calves the pChE level started to increase when they were 6 weeks old and reached a level of 5.7 μkat/1 ± 0.6 before slaughter at 6 months of age. The heifers did not show this increase. They had a level of around 2 μkat/1 throughout the investigation. The eAChE level at birth was 119 μkat/1 and increased slowly to a level of 145 μkat/1 at 6 months. No differences between the sexes were found.The cows suffering from parturient paresis had a pChE level of 1.80 μkat/1 ± 0.30 before treatment with calcium (Ca). The level decreased significantly (P ≦ 0.001) after Ca-infusion to a level of 1.67 ukat/1 ±0.29. Group IV had a pChE level of 1.65 μkat/1 ± 0.42 at parturition. Two to 4 months later the cows that had recovered from milk fever had a level of 1.61 μkat/1 ± 0.31 and the control cows 1.66 ukat/1 ± 0.48. No differences between the groups were found for the eAChE level.The findings show that parturition influences the pChE level in cows and that sex influences the pChE level in calves between 6 weeks to at least 6 months of age. Furthermore the elevated pChE level found in the cows suffering from parturient paresis before Ca infusion may be a further sign of a disturbance in the cholinergic system with a special preference to the neuromuscular junctions.     

Thrombocytes,Leucocytes and Packed Red Cell Volume in Piglets During the First two Weeks of Life

Number of platelets, leucocytes and packed red cell volume (PGV) have been determined in normal piglets during the first 2 weeks of life.A mean platelet count of 337 ± 79 at birth decreased during the first 2 days to 241 ± 48, followed by increasing numbers the next week to a maximum of 578 ±128 at 10 days after birth. Then a slight decrease to 492 ±115 on the 15th day was observed.The leucocyte counts were highest the first 30 hrs. of life, the mean count being 16.9. During this period, however, there was as wide a range as from 3.6 to 46.3. For the rest of the period the mean varied from 8.0 to 11.8, the counts ranging from 4.5 to 20.0.The mean PGV, which was highest at birth, decreased from a mean of 40.8 ± 6.1 to 32.9 ± 5.0 during the first 2 days. At 7 days of age the mean was 31.5 ± 3.8 but increased during the following week to 39.9 ± 3.6 on the 15th day.     

Changes in serum protein electrophoresis profiles and acute phase proteins in calves with diarrhea

Calf diarrhea leads to substantial economic losses in the livestock industry worldwide due to medical treatment costs, retarded growth performance, and even death. The objective of this study was to investigate changes in serum protein profiles and acute phase proteins in calves with diarrhea and identify the association between these changes and diarrhea. A total of 185 Korean beef calves were used and divided into 3 groups by age: 1 to 10 days (n = 46), 11 to 20 days (n = 65), and 21 to 30 days (n = 74). Blood and fecal samples were collected from each calf. Serum concentrations of total protein, protein fractions (albumin, α1-globulin, α2-globulin, β-globulin, and γ-globulin), haptoglobin (Hp), and serum amyloid A (SAA) were analyzed. Compared to calves without diarrhea, calves with diarrhea had significantly lower albumin concentrations at 11 to 20 days and 21 to 30 days of age (P = 0.017 and P = 0.000, respectively) and significantly higher α1-globulin fractions at 21 to 30 days of age (P = 0.01). Interestingly, α2-globulin fractions were significantly higher in diarrheic calves in all age groups, whereas γ-globulin fractions were significantly lower in calves with diarrhea aged 1 to 10 days, compared with normal animals. In calves with diarrhea, the concentration of Hp was significantly higher, whereas SAA levels were not different between normal and diarrheic calves. In addition, a positive correlation was found between α2-globulin and Hp (P = 0.0004). Taken together, these results provide useful information about the use of serum protein profiles and Hp as prognostic and diagnostic markers for animal health status.     

On The Normal Activities of Glucose-6-Phosphate Dehydrogenase and 6-Phospho-Gluconate Dehydrogenase in Bovine Erythrocytes

The activities of glucose-6-phosphate dehydrogenase and of 6-phos-pho-gluconate dehydrogenase have been determined in cows, heifers, bulls and calves. The material consisted of 80 RDM, 46 SDM, 31 Jersey animals older than 3 months, 16 newborn RDM calves and 29 fetuses of various breeds.

1. In RDM averages of 322 ± 56 units G6PD and 52.8 ± 12.2 units 6PGD per 100 ml PGV were found. In SDM 330 ± 43 units G6PD and 47.1 ± 9.2 units 6PGD were found, and in Jersey 315 ± 39 units G6PD and 49.2 ± 8.0 units 6PGD per 100 ml PGV. The activities of both dehydrogenases were shown to be normally distributed in all three breeds.
2. The 6PGD activities in SDM were significantly lower than in RDM, but no other breed differences between the mean activities were detected.
3. There is no relation between the age (apart from fetuses and newborn calves), and milk yield of the animals and the activities of G6PD and 6PGD in the erythrocytes.
4. Statistical treatment of the results demonstrates that there is no relation between the G6PD and 6PGD activities in the blood samples, and that the enzyme activities in units per 100 ml PGV is not correlated with MCHG.
5. Further, the statistical treatment shows that when measuring G6PD and 6PGD activities in erythrocytes, PGV is to be preferred to hemoglobin concentration as parameter.
6. In bovine fetuses G6DP activities more than twice as high as in adult erythrocytes were found, while the 6PGD activities were only slightly higher than in adult erythrocytes. After birth the high G6PD activities decreased over a period of 40 days to the normal level for mature cattle. The 6PGD activity also attains the normal level for older animals in approximately 40 days after birth.

     

Observations on Uterine Prolapse in Beef Cattle

Serum samples were obtained from 26 beef cows with uterine prolapse and from 15 with minor dystocia (controls). The serum of animals with uterine prolapse had significantly lower calcium concentration (mean ± S.D. = 8,22 ± 0,69 mg/dL, P≤0,01), higher phosphorus concentration (mean ± S.D. = 4,78 ± 1,75 mg/dL, P≤0,05) and lower calcium to phosphorus ratios (mean ± S.D. = 1,99 ± 0,88, P≤0,01) than for the control animals (means ± S.D. = 8,91 ± 0,75 mg/dL, 3,54 ± 1,41 mg/dL and 2,99 ± 1,41 respectively). Mild hypocalcemia (6,9 mg/dL-7,9 mg/dL) was present in 11 (42,3%) of the cows with prolapse as compared to only one (6,7%) of the controls. Hypophosphatemia was present in 11 (42,3%) of the animals with prolapse and in ten (66,7%) of the controls.

Eighteen (69,2%) of the animals with prolapse were alert and ambulatory when treated and 15 (57,7%) were known to have required help to deliver the calf. Of the cattle group with uterine prolapse, 14 (53,8%) were two years old, six (23,1%) were three years old, and six (23,1%) were four years of age or older.

It was concluded that mild hypocalcemia and some degree of dystocia were associated with the uterine prolapses. The phosphorus results were equivocal but the high incidence of hypophosphatemia may reflect a phosphorus deficient diet.

     

Chromatographic Studies of Sera from Calves Vaccinated with Brucella Abortus, Strain 19

The presence of antibody was detected by agglutination tests in the serum of calves four days after vaccination with Brucella abortus strain 19. Titres had reached a maximum by seven to ten days post-vaccination. Sucrose density-gradient ultracentrifugation demonstrated that the earliest antibodies were macroglobulins, IgM (19Sγ; γM)-globulins. Lighter antibodies, IgG (7Sγ₂; γG)-globulins, appeared a few days later. With time, antibody titres fell, IgM declining somewhat more quickly than IgG. After revaccination some seven months later, there was a rapid rise in both IgM and IgG.

Anion-exchange column chromatography (DEAE-cellulose) and gel filtration (Sephadex G-200) were applied in separating the two forms of antibody. The former method, in which a gradient buffer system was used, proved to be the more efficient; the IgG antibodies apeared in early eluates at pH 7.8 to 8.0 and low ionic strength, 0.03M, whereas IgM was eluted late when the pH had fallen below 6.0 and the molarity had increased to beyond 0.2. DEAE cellulose chromatography detected IgG as well as IgM sera collected as early as five days after vaccination.

     

Blood biochemical values in Japanese Black calves in Kagoshima Prefecture,Japan

To obtain blood biochemical basic data of Japanese Black calves in Kagoshima Prefecture, Japan, blood samples were obtained from 582 clinically healthy calves on 27 farms. Calves were divided into three stages: the suckling stage (between 14 and 90 days of age, n=191), the early growing stage (between 91 and 180 days of age, n=200) and the late growing stage (between 181 and 270 days of age, n=191). The mean concentration of total cholesterol, triglyceride, nonesterified fatty acids, calcium and zinc, and the mean activities of γ-glutamyltransferase and alkaine phospatase in the suckling stage were significantly higher than those in the early and late growing stages (P<0.01). The mean concentration of total protein, albumin and globulin increased gradually with growing. The mean concentration of beta-hydroxybutyrate in the suckling stage was below 150 µmol/l, however, it elevated above 400 µmol/l in the early and late growing stages. The mean concentration of copper concentration was above 70 µg/dl in all stages. The mean concentration of zinc was between 90 and 110 µg/dl in all stages. These results suggest that the blood biochemical values of Japanese Black calves vary with growing stages, and the blood parameters obtained in this study are considered useful as indices for health management of Japanese Black calves.     

Evaluation of the Total Carbon Dioxide Apparatus and pH Meter for the Determination of Acid-Base Status in Diarrheic and Healthy Calves

Three simple tests of acid-base status were evaluated for field use. Blood samples were collected from 20 diarrheic and 24 healthy calves less than six weeks of age. One sample was collected anaerobically and immediately analyzed on a blood gas analyzer. The other samples were used for measurement of blood and serum pH using a pH meter and pH paper, and for serum total carbon dioxide (TCO₂) using a TCO₂ apparatus. The TCO₂ apparatus gave the best results and would be useful in the field. TCO₂ apparatus measurements had a high correlation, r=0.91, with blood gas analyzer blood bicarbonate values. Healthy calves have a serum TCO₂ content of 30 mmol/L and bicarbonate requirements for correcting metabolic acidosis in diarrheic calves can be calculated:

Bicarbonate required (mmol) = (30-TCO₂) × Body Weight × 0.6 This can be converted to grams of sodium bicarbonate by dividing by 12.

     

Acute Metabolic Effects of Clenbuterol in Calves

The acute metabolic effects of clenbuterol were studied in calves. Clenbuterol was given intravenously at a dose of 1 µg/kg body weight. Glucagon was used to increase insulin secretion. Pretreatment with clenbuterol did not change the glucagon-induced hyperglycaemia, but the serum levels of insulin were significantly higher. Clenbuterol showed a significant lipolytic effect. The post prandial increases in glucose and insulin were significantly higher in clenbuterol treated calves. The findings are in accordance with results from earlier studies where clenbuterol was given orally in much higher doses.     

Effect of Injectable Iron-Dextran on Dairy Calves and Lambs

Ten Holstein calves, 10 Jersey calves, 7 single lambs, and one lamb from each of ten sets of twins were injected with an iron-dextran solution shortly after birth. These were paired with an equal number of untreated animals that formed the control groups. Percentage of hemoglobin and body weights were recorded periodically up to 16 weeks of age for the calves and 21 weeks for the lambs.

Percentage of hemoglobin in the blood of treated calves was generally higher than that of untreated calves but body weights between groups were not significantly different. In the lambs there was no significant difference in percentage of hemoglobin or body weights between the treated and control groups. The results indicate that under the confined system of management as outlined, there was no advantage in administering iron-dextran to young calves or lambs.

     

In vitro Studies of Group E Streptococci in Swine Leukocytes I. Phagocytic and Bactericidal Properties of Polymorphonuclear Leukocytes from Swine

Serum from both immune and nonimmune ten-week-old swine contained factors which promoted phagocytosis of group E Streptococci (GES). The factors in nonimmune serum, which were heat labile at 70°C for ten minutes, were less efficient than the factors present in immune serum.

Bactericidal activity of the polymorphonuclear (PMN) leukocytes against GES was observed with serum from both immune and nonimmune ten-week-old swine, as well as with serum from normal sows and piglets. However, the bactericidal activity of PMN leukocytes in serum from either normal sows or immune ten-week-old swine was greater than the bactericidal activity of PMN leukocytes in either piglet serum or serum from nonimmune ten-week-old swine. When the serum was either heated to 70°C for ten minutes or treated with 2-mercaptoethanol, bactericidal activity of PMN leukocytes against GES was only observed in the presence of immune serum.

     

初乳饲喂次数对娟姗犊牛生产性能的影响

为研究探讨初乳饲喂次数对娟姗犊牛生产性能的影响,试验选取初生重接近的健康娟姗犊牛20 头,随机分为4 组,分别为对照组、试验I组、II组和III组,每组5 头犊牛,试验期为60 天。4 组犊牛出生当日饲喂两次初乳,首次初乳量按照体重的10.0%进行灌服,第2次初乳于出生后6~8 h按照体重的5.0%进行饲喂。4 组犊牛出生当日在产房饲养,2日龄时均转为室外犊牛岛单栏饲养。2日龄后,对照组每天上午06:00和下午16:00时各饲喂常乳1次,2~6日龄每次饲喂1.50 L,7~20日龄每次饲喂1.80 L,21~35日龄每次饲喂2.50 L,36~60日龄每次饲喂3.00 L,自7日龄开始犊牛自由采食颗粒料。试验Ⅰ组、Ⅱ组、Ⅲ组分别继续饲喂初乳至犊牛2日龄、4日龄、6日龄后再饲喂常乳,饲喂时间和饲喂量与对照组一致。结果表明:(1)在饲喂初乳后48 h、72 h、96 h,试验组与对照组犊牛血清免疫球蛋白g(IgG)均差异显著(p<0.05),120 h、144 h、168 h,试验Ⅰ组与对照组比较,犊牛血清IgG含量差异不显著(p>0.05),试验Ⅱ组、Ⅲ组血清IgG含量与对照组相比,差异极显著(p<0.01)。(2)随着初乳饲喂次数的增加,可有效降低犊牛20日龄内腹泻发生率,试验Ⅰ组、Ⅱ组、Ⅲ组较对照组比较犊牛腹泻发生率分别降低9.5%、22.5%、36.5%,治疗犊牛腹泻总成本较对照组分别下降12.0 元、43.2 元、76.8 元,3 组试验组犊牛成活率为100.0%。(3)初乳饲喂次数的增加,使0~60日龄娟姗犊牛平均日增重(ADG)升高,试验组与对照组相比较,日增重均差异极显著(p<0.01),分别增加16.7 g、33.3 g、80.0 g。试验Ⅱ组、Ⅲ组较试验Ⅰ组ADG差异也极显著(p<0.01)。综合考虑,建议娟姗犊牛饲喂初乳至6日龄,可降低犊牛腹泻发生率、减少治疗费用,提高犊牛成活率及ADG。     

A retrospective study of the relationship between clinical signs and severity of acidosis in diarrheic calves

A retrospective study of 123 calves under two months of age with signs of diarrhea was performed to investigate the relationships among the calf's demeanor, dehydration, rectal temperature, and base deficit. The severity of dehydration, hypothermia, and metabolic acidosis were associated with level of depression. Clinical signs and age of calf could be used to predict the severity of acidosis. Acidosis was more severe in calves over eight days of age and also increased in severity with the degree of depression. The most severe metabolic acidosis was seen in calves over eight days of age presented in sternal or lateral recumbency; the base deficit in these groups was 16.3 ± 8.3 (means ± 1SD) and 20.3 ± 10.1 mmol/L respectively, and on average these calves require 2.4 and 3.0 L respectively of 1.3% sodium bicarbonate solution to correct the acidosis.     

Nematode control in suckler beef cattle over their first two grazing seasons using a targeted selective treatment approach

Background

With concerns over the development of anthelmintic resistance in cattle nematode populations, we must re-examine our approach to nematode control in cattle. Targeted selective treatments (TST), whereby individual animals are treated instead of entire groups, are being investigated as an alternative. The study objective was to determine if anthelmintic usage could be reduced using a TST-based approach to nematode control in spring-born suckler beef cattle over their first and second grazing seasons (SGS) without affecting performance. In the first grazing season (FGS), 99 calves with an initial mean (s.d.) calf age and live weight on day 0 (June 28^th 2012) of 107 (23.1) days and 160 (32.5) kg, respectively, were used. The study commenced on day 0 when calves were randomised and allocated to one of two treatments; 1), standard treatment (control) and 2), TST. Control calves were treated subcutaneously with ivermectin on days 0, 41 and 82 in the FGS. All calves were treated with ivermectin on day 124 and housed on day 133. In the SGS, only heifer calves from the FGS were used and control heifers were treated with ivermectin on day 393. Animals were weighed, blood and faecal sampled every three weeks. The TST animals were treated with ivermectin if thresholds based on a combination of plasma pepsinogen concentrations, faecal egg count and/or the presence of Dictyocaulus viviparus larvae in faeces (FGS only) were reached.

Results

No TST calves reached the treatment threshold criteria in the FGS. The FGS average daily live weight gain (ADG ± s.e.m.) for control and TST group calves was 0.89 ± 0.02 kg and 0.94 ± 0.02 kg day⁻¹, respectively (P = 0.17). In the SGS, all heifers were treated with ivermectin on day 431 due to clinical signs of respiratory disease. The ADG for control and TST heifers from turnout on day 321 to day 431 was 0.90 ± 0.04 and 0.80 ± 0.04 kg day⁻¹, respectively (P = 0.03).

Conclusions

Spring-born FGS suckler beef calves require minimal anthelmintic treatment to maintain performance. In contrast, clinical parasitic disease may develop in the SGS unless appropriate anthelmintic treatment is provided.     

Experimental Adenovirus Infection in Calves

Twenty-four dairy calves ranging in age from six to 15 weeks were divided so that 10 were inoculated with bovine adenovirus serotype 1 (BA-1), eight were inoculated with bovine adenovirus serotype 3 (BA-3), and six were inoculated with control tissue culture and fluids.

Post-inoculation serum samples from most of the calves presented evidence of adenovirus infection, but none of the animals exhibited signs of respiratory or enteric disease. Histopathological examination of lung tissue was not considered to be specific for adenovirus pneumonia, but was characterized by peribronchial cuffing and slight aspiration pneumonia. BA-1 was not isolated from any of the inoculated calves, and BA-3 was only recovered from the feces of two animals.

Reasons for the discrepancy between these results and those of other workers are considered, and the etiology of peribronchial cuffing is briefly discussed.