Life In Calves Research Articles

Complicações neonatais onfalógenas – relato em um bovino

Care for newborn animals is important, as they are vulnerable. Adequate and specific management until weaning requires health care at the time of birth, with healing of the navel and the supply of colostrum being fundamental measures to ensure immunity. Omphalogenic pathologies range from mild conditions to serious problems such as sepsis, putting the calf's life at risk. As measures adopted to prevent omphalogenic diseases, care must be taken to clean and antisepsis the cord and the place where the animal will continue to be housed, which must be clean and dry. The study reports the case of an animal with a hernia and umbilical infection. A two-month-old Girolando calf, referred to the Franca Veterinary Hospital (UNIFRAN), with increased volume in the region, anorexia, apathy, tachypnea and cough. As clinical management, clinical, imaging and hematological tests were carried out, where the tests suggested multiple intracavitary abscesses. The clinical treatment instituted was based on antibiotics, anti-inflammatories, bronchodilators, supportive therapy and daily dressings of the umbilical cord. These measures aimed to improve the infection and restore respiratory problems. After the clinical condition improved, the animal underwent surgery to correct the umbilical hernia, with the procedure performed successfully. Post-operatively, the animal performed well, was medicated with antibiotics, vitamin complexes and anti-inflammatories, and was discharged from hospital 21 days after the surgery. On the property, the animal had a clinical relapse resulting in death from septicemia.

Growth Performance and Fecal Microbiota of Dairy Calves Supplemented with Autochthonous Lactic Acid Bacteria as Probiotics in Mexican Western Family Dairy Farming.

Probiotic supplementation in dairy cattle has achieved several beneficial effects (improved growth rate, immune response, and adequate ruminal microbiota). This study assessed the effects on the growth parameters and gut microbiota of newborn dairy calves supplemented with two Lactobacillus-based probiotics, individually (6BZ or 6BY) or their combination (6BZ + 6BY), administrated with the same concentration (1 × 109 CFU/kg weight) at three times, between days 5 and 19 after birth. The control group consisted of probiotic-unsupplemented calves. Growth parameters were recorded weekly until eight weeks and at the calves' ages of three, four, and five months. Fecal microbiota was described by high-throughput sequencing and bioinformatics. Although no significant effects were observed regarding daily weight and height gain among probiotic-supplemented and non-supplemented calves, correlation analysis showed that growth rate was maintained until month 5 through probiotic supplementation, mainly when the two-strain probiotics were supplied. Modulation effects on microbiota were observed in probiotic-supplemented calves, improving the Bacteroidota: Firmicutes and the Proteobacteria ratios. Functional prediction by PICRUSt also showed an increment in several pathways when the two-strain probiotic was supplemented. Therefore, using the three-administration scheme, the two-strain probiotic improved the growth rate and gut microbiota profile in newborn dairy calves. However, positive effects could be reached by applying more administrations of the probiotic during the first 20 days of a calf's life.

Invited Review: Bovine neonatal morbidity and mortality - causes, risk factors, incidences, sequelae and prevention.

The neonatal period may be defined as the first month of the calf's life; it may be considered part of the fourth trimester. It is the most hazardous due to the immaturity of the neonate's immune system and the environmental challenge from infections, the main causes of both bovine neonatal morbidity and mortality. The five most common morbidities causing mortality in neonatal calves are, in descending order, gastro-intestinal infections, respiratory infections, abomasal disorders, umbilical infections and developmental abnormalities. This review describes the aetiology, incidence, risk factors and sequelae of these common morbidities and highlights current preventive strategies both at farm- and national-levels.

The current situation on bovine leukemia in Dagestan and methods of its diagnosis

The article presents the current situation on bovine leukemia in the municipalities of Dagestan and a comparative analysis of serological and molecular-genetic methods of diagnosis. In municipal districts, urban districts and areas of animal husbandry for the first half of 2022, the number of animals examined by immune diffusion 531111 identified 2871, infected with the leukemia virus, which is 0,5 % from the number diagnosed. The degree of infection of livestock with bovine leukemia virus in rural areas varied from 0,01 to 5,2 %. The average coverage rate of serological studies of animals on leukemia – 57,2 %. Hematological studies of seropositive animals were not carried out during the analyzed period. 79 new leukemia-affected points have been registered, 95 unhealthy points have been transferred since 2021, only 3 points have been rehabilitated. As on 01.07.2022, 171 leukemia-affected points are registered, including 38 in agricultural enterprises, 4 of them in breeding farms, 27 farms and 106 farms. A comparative analysis of the data on the carrier of antibodies and DNA provirus showed that ELISA revealed 7 animals more carriers of antibodies than in AGID, PCR study revealed 14 and 7 animals more carriers of DNA provirus than carriers of antibodies in AGID and ELISA, respectively. To maximize the detection of seropositive BLV of animals, the integrated use of AGID, ELISA and PCR methods as a promising system in anti-leukemia measures is proposed. The introduction of ELISA and PCR diagnostics into the veterinary practice of the Dagestan Republic will make it possible to determine virus transmission in animals from the first day after birth (ELISA) and from the 20th day of the calf's life (PCR), as well as to increase the effectiveness and shorten the duration of anti-leukemia measures the final stages of the recovery of agricultural enterprises from leukemia infection.

Organization and feeding normalized growing repair heifers

The article reflects the initial state of research on the long-term maintenance heifers of Ukrainian black and white dairy cattle. Research aimed at obtaining a high-performance group of dairy cows regarding farmers' zonal characteristics of feed production technology and advanced economies of Western Europe. It should be noted that western milk production technologies have drawbacks that should be considered when implementing them in our farms. These technologies use the concentrated feeding of cattle intended for the repair group. Typically, these farms' cows eat bad food and poor voluminous use of pasture, which is an obstacle in the purchase of cows and calves, taking into account their high purchase price. The main advantages of Western technology feed an extra shredding of bulky feed to the length of stems 0.3–0.5 mm and use free access to the feed table on which the feed, which is composed of plush corn and feeds additional concentrates at milking time. Thus, the type of concentrate feeding cows has a positive, but at the same disadvantage, especially in feeding heifers repair. Cow barrenness is high (30 % or more), and the duration limits the effective use of cattle to three years. Top management of our technology can actively use cows for 5–6 or more years with barrenness no higher than 8 %. Thus, the theoretical issue of full feeding of young cattle intended for herds of repair, incredibly high performance, continues to be studied. Our research task was to examine the characteristics of the formation of future milk production of repair heifers depending on age, level of energy, and protein supply. It is a well-known fact that the early introduction of grain concentrates into the diet of month-old calves helps accelerate rumen development. This dry feed during this critical period of the calf's life will also ensure the regular and harmonious functioning of the gastrointestinal tract. Feeding whole grains, corn, and oats during this period will help strengthen the chewing muscles and improve the functioning of the salivary glands. Targeted breeding of repair heifers is one of the main tasks of animal breeders. The level of raising heifers in all age periods significantly impacts the health of animals, their subsequent milk productivity, reproductive capacity, and terms of productive use, and largely determines the efficiency of the dairy industry. Therefore, the organization and technology of rearing young animals for repair should be based on individual growth and development laws and contribute to the formation of animals with a strong constitution and high productivity. After all, it is known that the underdevelopment of organs due to insufficient feeding and inappropriate conditions of maintenance in one period of cultivation leaves negative consequences, even if the next period of animal development takes place under favorable organizational and technological conditions.

Movement behaviour after birth demonstrates precocial abilities of African savannah elephant, Loxodonta africana, calves

Living in groups has many benefits including predator protection and information sharing that can outweigh the associated costs. African savannah elephants live in a matriarchal fission–fusion social structure where groups merge or split depending on the relative costs of group living. However, elephants are also nonsynchronous breeders which may cause optimal movement patterns to differ between group members, particularly around parturition. Both the mother and the group must assess whether the benefits outweigh the costs of group cohesion. Understanding the impact of gestation, parturition and the presence of a newborn calf on the mother's movement patterns could provide key insights into the drivers of fission–fusion social dynamics. Here, we examined the relationship between reproductive state and movement using GPS tracking data collected during 23 parturitions from multiparous elephants (≥ second calving) and three from primiparous females. We analysed daily mean speed before, during and after parturition, and used a three-state hidden Markov model to determine whether parturition results in a distinctive change in speed. The results show that, although speed decreased on the estimated parturition date, parturition could only be detected in four of 23 multiparous parturition events when placed in the context of speed over a 2-month period. Furthermore, the speed on the day before and the day after parturition (i.e. first complete day of the calf's life) was not significantly different from the yearly mean. By contrast, a speed decrease was detected in the limited sample of primiparous females but was of short duration. Our results indicate that the precocial abilities of calves facilitate the maintenance of group cohesion within the matriarchal fission–fusion social structure of elephants. We speculate that, alongside cognitive development, elephants may have evolved a long gestation period to facilitate an advanced stage of fetal physical development. • We analysed the movement behaviour of parturient African savannah elephants. • Gestation, parturition and neonatal calves had little impact on mothers' movements. • We demonstrate the precocial abilities of elephant calves. • Movement after birth could be a significant advantage for a social species. • Extended gestation of elephants may have evolved for advanced fetal development.

Influence of skimming of calves with skim milk substitute on physiological condition and productivity

The high demand for protein during this period of the calf's life is due to the active growth of muscle tissue, and protein is the structural material of all organs. A lack of protein in the diet of calves contributes to a delay in their growth and an excess to the expenditure of additional energy for the deamination of excess amino acids and the elimination of the corresponding decay products through the excretory system of the body. The younger the calves, the higher the protein level in their diet should be. The work aimed to establish the most effective protein norms in the composition of skim milk substitutes for calves over 65 days of age. The study of the influence of feeding skims milk substitute on calves' physiological state and productivity was carried out on four groups of bulls. All tested skim milk replacers varied in protein content but were almost the same in all nutritional parameters. The main ingredients of skim milk substitutes (ZOM 1) for calves of group I were, %: milk proteins – 70, vegetable proteins (soy + wheat) – 29, vitamin and mineral complex, probiotic culture – 1. For calves of group II (ZOM 2) used,%: milk proteins – 70, vegetable proteins (soy + wheat protein) – 29, vitamin-mineral complex – 1. protein) – 29, vitamin and mineral complex – 1. Studies have shown that skim milk substitutes in calves feeding, containing 20 and 22 % protein in the composition of KR-2 compound feed 10 % by weight, was reflected in the improvement of the morpho-biochemical design of the blood. At the same time, there is a tendency to an increase in the concentration of total protein in the blood serum by 3.1 and 3.3 % with a decrease in the amount of urea by 3.5 and 5.2 %, which made it possible to increase the average daily gain in live weight to 3.1 % while reducing costs feed and its price by 1.5 and 0.9 percent.

Short communication: Selection of extended-spectrum β-lactamase-producing Escherichia coli in dairy calves associated with antibiotic dry cow therapy—A cohort study

Antimicrobial residues in milk have been discussed as a possible selector for Enterobacteriaceae that produce extended-spectrum β-lactamases (ESBL) in dairy herds. Such residues are found in waste milk after antibiotic treatment of mastitis, but antibiotic dry cow therapy might also lead to antibiotic residues in colostrum and in milk during early lactation. While it is known that feeding of waste milk selects ESBL bacteria in calves, this was not investigated for colostrum yet, which is supposed to contain much lower antibiotic concentrations than waste milk. In this observational prospective case study on 2 farms, we hypothesized that blanket dry cow treatment with β-lactams would have more selective (here: increasing) effects on ESBL concentrations than selective (here: individually chosen) antibiotic dry cow therapy. Thus, we compared concentrations of ESBL-producing Enterobacteriaceae in feces of calves (n = 50) at 2 dairy farms with different management of antibiotic dry cow therapy. Considerably higher concentrations of ESBL-producing Escherichia coli were observed in blanket antibiotic dry cow therapy on d 3 of the calf's life (7.6 vs. 5.3 log cfu/g of calf feces). Both farms used narrow-spectrum penicillin combined with aminoglycosides for drying off, and the majority of ESBL isolates (93%) were co-resistant to aminoglycosides. No waste milk was fed to calves and no calf was treated with β-lactam antibiotics or aminoglycosides during the first 3 d of life, thus differences were most likely associated with different frequency of antibiotic dry cow therapy on farms (19 of 25 mother cows on farm A, 9 of 25 on farm B). Even though the presumable selection effect of antibiotics used for drying off decreased within the next 3 wk, this result further emphasizes the need for the reduction and prudent use of antibiotic dry cow therapy on farms.

Assessment the Calf’s Welfare Due to The Gender, Number of Offspring and Calving Status in Holstein Calves

The aim of the present paper was to study the influence of gender, number of offspring, calving status on both health and welfare. Out of 3000 heads, data for 429 Holstein female calves and 551 male calves which have been born during one year were used with computer records. The result suggested that abnormal behaviour during 1st 12 hours of calf's life have been significantly affected by twinning and dystocia .The presence and duration of behaviour related to respiratory, digestive or mixed disorders were significantly higher in females, the calf’s growth rate was higher in male than female with significance difference, while its birth weight was significantly higher in dystocia than calves from normal parturition. There was a non-significant effect of calf gender, number of offspring and parturition state on calves weaning age. It could be concluded that Calf gender, number of offspring and parturition state have a different effects on behaviour and growth performance of calves from birth till weaning. Abnormal behaviours during the first 12 hours of calf's life as delayed sternal recumbancy, standing, abnormal suckling have been significantly affected by twinning and dystocia and not significantly affected by calf sex. Presence and duration of behaviour related to respiratory, digestive or mixed disorders were significantly higher in females than males, where these disorders were significantly higher in case of dystocia and twinning births. Culling of cows with incidence of twinning is recommended to control the decreased fertility, decreased total number of calves over the lifespan of the cow, and decreased milk production.

A study on Calf’s Behavior and Growth Performance in Relation to Gestation Period and Lactation Season

The present study aimed to assess the impact of the length of the gestation period (GPL) and a number of lactation season of cows on behavior and growth performance in calves from birth until weaning. The presence of abnormal behavior during 1st twelve hours of the calf's life as delayed Sternal recumbency and standing or abnormal suckling was not significantly affected by GPL. Also, the duration and frequency of behavior related to respiratory, digestive or mixed disorders had a non-significant variation between groups of different gestation period length. However, the increase in GPL had the lowest percentage and duration of behavior related to respiratory and digestive disorders. Calves with the longest GPL had a significantly higher birth weight and it had a significant effect on pre-weaning growth rate. On the other side, the presence of abnormal behavior during the first twelve hours of the calf's life as delayed Sternal recumbency and standing or abnormal suckling were higher in 3rd parity. The number of lactation season had no significant effect on the duration and frequency of behavior related to respiratory, digestive or mixed disorders. The birth weight of calves was higher in the third parity group (36.73 kg) than other parities, but the differences didn't reach the significance, moreover, the weaning age and pre-weaning growth rate did not affect by the lactation season number. There was a negative correlation between abnormal behavior and the pre-weaning growth rate. There was a positive correlation between duration of abnormal behavior and the weaning age.

Daytime mother-calf relationships in reticulated giraffes (Giraffa cameloparadalis reticulate) at the Kyoto City Zoo.

The present study quantitatively assesses the relationships between a reticulated giraffe mother and her first- and second-born calves during the first 22 months of the older calf's and the first 12 months of the younger calf's life at the Kyoto City Zoo, Japan. The mother permitted her calves to suckle at over 70% of their suckling attempts in the first month after their births, and the calves ceased suckling spontaneously in 65 to 70% of the suckling bouts. From the second month on, she showed a clear tendency to reject the calves' suckling attempts and terminated almost all of their suckling bouts, which resulted in approximately 60 sec or less of suckling duration per bout. The frequency of proximity between the mother and her calves remained at 20 to 30% throughout the first year, with no apparent developmental changes being evident. The mother was mainly responsible for terminating proximity by walking away from her calves throughout their first year after birth, while both calves were mainly responsible for attempting proximity by approaching their mother after reaching 2 months of age. Our study also showed that the giraffe mother became pregnant again while nursing her calves and ceased lactation (i.e., weaned the calves) before the fetus's growth started accelerating.

Validity of physiological biomarkers for maternal behavior in cows — A comparison of beef and dairy cattle

The objectives of the present study were to evaluate the suitability of potential biomarkers for maternal ability in cattle, and in addition to test the hypothesis that dairy cows have a less pronounced motherliness than beef cows. Therefore, maternal behavior of 20 Simmental beef-type (S) and 20 German Black Pied (dairy-type) Cattle (BP) was assessed on the 2nd and again on the 3rd day of the calf's life. Measurements included the frequency of interactions between cow and calf, the cow's willingness to defend her calf, the overall maternal behavior, saliva cortisol, saliva oxytocin, heart rate, and thermal images of the eye (ET). Mixed model analysis revealed that BP had significantly (P<0.05) higher oxytocin (88.6±9.2 vs. 62.8±9.2pg/ml saliva) and cortisol (1.3±0.1 vs. 1.0±0.1ng/ml saliva) levels, but lower heart rates (80.0±2.0 vs. 95.8±2.0bpm) than S cows. Simmental (beef) cows showed more defensive behavior (3.5±0.2 vs. 2.7±0.2 scores), but fewer total interactions between cow and calf (8.1±1.4 vs. 13.8±1.4), compared to BP (dairy). However, with the exception of heart rate and overall maternal behavior, breed differences tended to diminish from the 2nd to the 3rd day of the calf's life. Repeatabilities ranged from 9±23% (ET) to 77±7% (maternal behavior measured on a visual analogue scale), and correlations between physiological parameters and behavior differed between breeds and were generally at a low level. In conclusion, beef cows do not seem to be per se more maternal compared to dairy cows, and the assessed parameters are of limited use as biomarkers for maternal behavior.

Associations between milk intake and activity in the first days of a calf's life and later growth and health

We examined whether calves’ milk intake and activity in the days after birth predict later growth and the risk of illness. Female Holstein calves (n=130) were housed in individual pens where they were allowed ad libitum milk from birth to 5 days of age. Daily milk intakes were recorded and accelerometers attached to the calves measured time spent standing and lying down. After 5 days, calves were housed in group pens with four to nine calves per group and allowed 12L/day of milk and ad libitum hay and starter from automated feeders. Calves were weighed at birth (birth weight=BW) and at 28 days of age and health status was determined daily. Digestible energy (DE) intakes were calculated from feed intakes. During days 2–4, there were large differences among calves in the amount of milk consumed, which ranged from 7.3% BW/day (2.4L/day) to 30.5% BW/day (12L/day) with a median of 16.3% BW/day (6.7L/day). Twenty-one calves were treated for illness from days 6 to 28. These calves had lower milk intakes on days 2, 3 and 4 than calves that remained healthy (P<0.05). For the calves that did not become ill, milk intake on day 4 was correlated (r=0.29; P<0.01) with ADG from days 0 to 28 and correlated (r=0.33; P=0.03) with the residual body weight on day 28 (when birth weight and digestible energy intakes from days 5 to 28 were accounted for using multiple regression). Time spent standing from days 2 to 4 varied between calves but was not correlated with BW, milk intake during days 2–4, or weight gains to day 28 (P>0.10). Very young calves can drink large quantities of milk, and the calves that drink the largest amounts in the first days of life have greater long-term growth rates and are less likely to become ill. Milk intake may be a better sign of early calf vigour than activity levels.

Influence of Predator Harvest, Biological Factors, and Landscape on Elk Calf Survival in Idaho

ABSTRACT We evaluated survival of elk (Cervus elaphus) calves on 2 contrasting study areas in north‐central Idaho, USA, from 1997 to 2004. Recruitment was modest (&gt;30 calves:100 F [calves of either sex: F elk 1 yr old]) and stable on the South Fork study area and low (&lt;20 calves:100 F) and declining on the Lochsa study area. The primary proximate cause of calf mortality on both study areas was predation by black bears (Ursus americanus) and mountain lions (Puma concolor). We experimentally manipulated populations of black bears and mountain lions on a portion of each study area. Black bear harvest (harvest density/600km2) initially doubled on the Lochsa treatment after manipulating season bag limits. Mountain lion harvest also increased by 60% but varied widely during the manipulation period. Harvest seasons were closed for black bears and mountain lions on the treatment portion of the South Fork study area. Using the Andersen—Gill formulation (A‐G) of the Cox proportional hazards model, we examined effects of landscape structure, predator harvest levels, and biological factors on summer calf survival. We used Akaike's Information Criterion (AICc) and multimodel inference to assess some potentially useful predictive factors relative to calf survival. We generated risk ratios for both the best models and for model‐averaged coefficients. Our models predicted that calf survival was influenced by biological factors, landscape surrounding calf locations, and predator harvest levels. The model that best explained mortality risk to calves on the Lochsa included black bear harvest (harvest density/600 km2), estimated birth mass of calves, and percentage of shrub cover surrounding calf locations. Incorporating a shrub X time interaction allowed us to correct for nonproportionality and detect that effect of shrub cover was only influential during the first 14 days of a calf's life. Model‐averaging indicated that estimated birth mass of calves and black bear harvest were twice as important as the next variables, but age of calves at capture was also influential in calf survival. The model that best explained mortality risk to calves on the South Fork included black bear harvest, age of calves at capture, and gender of calves. Model‐averaging indicated that age at capture and black bear harvest were twice as important as the next variable, forest with 33–66% canopy cover (Canopy 33–66). Risk to calves decreased when calves occupied areas with more of this forest cover type. Model‐averaging also indicated that increased mountain lion harvest lowered calf mortality risk 4% for every 1‐unit increase in lion harvest (harvest density/600 km2) but was lower (&lt;25%) in importance compared to age at capture and black bear harvest. Our results suggest that levels of predator harvest, and presumably predator density, resource limitations expressed through calf birth mass, and habitat structure had substantial effects on calf survival. Our results can be generalized to other areas where managers are dealing with low calf elk recruitment. However, because factors vary spatially, a single management strategy applied in different areas will probably not have the same effect on calf survival.

Behavioral aspects of sleep in bottlenose dolphin mothers and their calves

Adult dolphins are capable of sleeping with one eye open and exhibiting slow wave activity in the electroencephalogram (EEG) of one hemisphere at a time. The aim of this study was to examine the postpartum sleep behavior of bottlenose dolphin calves and their mothers. The behavior of three dolphin mother–calf pairs was monitored from birth to 13 months postpartum. Dolphin mothers and their calves exhibited a complete disappearance of rest at the surface for a minimum of 2 months postpartum, swimming in echelon formation on average in 97–100% of the observation time. Calves surfaced to breathe more often than their mothers between the postpartum age of 2 and 8 weeks. During the first postpartum month two dolphin mothers surfaced with both eyes open on average in 93 and 98% of the time while in their calves both eyes were open in 90 and 60% of the cases. In calves, the eye directed toward the mother was open more often (on average in 95% of all observations in calf 1 and 99% in calf 2) than the eye directed to the opposite side (82% in calf 1 and 60% in calf 2). Our data indicate that dolphin mothers and calves are highly active and vigilant during the initial period of the calf's life, continuously monitoring their position relative to each other by sight during wakefulness and sleep. We hypothesize that episodes of EEG slow wave activity at this time are likely to be brief, fragmenting EEG defined sleep into short episodes.

Allosuckling in cattle: Gain or compensation?

The objective of this study was to assess the impact of allosuckling on the growth of calves in a herd of domestic cattle. We determined (i) if allosucking calves achieved a better weight gain than non-allosucking calves ingesting milk surplus to maternal milk supply or if they were compensating for growth and/or nutritional deficiency, and (ii) if the growth and development of the calf is affected by allonursing behaviour of its dam. If a compensatory function of the behaviour was valid, then calves should compensate for a lower birth body mass and/or maternal nutrient insufficiencies (‘maternal sucking rate’, i.e. a low frequency of acceptance of the calf's sucking attempts by its mother) through allosuckling. Observations were made in a socially stable group of 21 lactating cows and their 18 calves (7 males and 11 females) from birth until 203 days of the calf's life. During 289 h of observation 389 sucking attempts and 1404 suckling bouts were recorded, 27% of sucking attempts and 19% of suckling bouts being non-filial. All allosucking calves sucked their mothers frequently. Thus, allosuking in calves did not mean a complete failure of maternal care provided to filial calves. The calves that allosucked most frequently tended to grow less intensively (growth gain calculated from birth and weaning weights) and tended to reach a lower weaning weight than calves sucking non-maternal dams with lower frequency (GLM, F (1,17) = 3.23, P = 0.063, F (1,17) = 4.75, P = 0.046, respectively). Growth gain or weaning weight of the filial calves was not affected by allonursing frequency of the mother ( P = 0.66, P = 0.66, respectively). A higher incidence of allosucking was predicted in calves with lower birth weight (GEE, χ ( 1 ) 2 = 3.73 , P = 0.05), and in calves with lower maternal sucking rate ( χ ( 1 ) 2 = 3.99 , P = 0.05). Moreover, birth weight and maternal sucking rate influenced allosucking frequency interactively ( χ ( 1 ) 2 = 4.45 , P < 0.05). In conclusion, the cattle calves that frequently sucked non-maternal dams were most likely compensating for some deficiency, such as low birth weight and/or insufficient supply of maternal milk. This behaviour did not have a negative effect on the growth of progeny of the allonursing dams. Our results supported the hypothesis that allosuckling could be a behaviour through which the calves compensate for low birth weight and/or nutritional deficiency.

Social structure in migrating humpback whales (Megaptera novaeangliae)

Although largely solitary, humpback whales exhibit a number of behaviours where individuals co-operate with one another, for example during bubble net feeding. Such cases could be due to reciprocal altruism brought on by exceptional circumstances, for example the presence of abundant shoaling fish. An alternative explanation is that these behaviours have evolved through kin selection. With little restriction to either communication or movement, diffuse groups of relatives could maintain some form of social organization without the need to travel in tight-nit units. To try to distinguish between these hypotheses, we took advantage of the fact that migrating humpback whales often swim together in small groups. If kin selection is important in humpback whale biology, these groups should be enriched for relatives. Consequently, we analysed biopsy samples from 57 groups of humpback whales migrating off Eastern Australia in 1992. A total of 142 whales were screened for eight microsatellite markers. Mitochondrial DNA sequences (371 bp) were also used to verify and assist kinship identification. Our data add support to the notion that mothers travel with their offspring for the first year of the calf's life. However, beyond the presence of mother-calf/yearling pairs, no obvious relatedness pattern was found among whales sampled either in the same pod or on the same day. Levels of relatedness did not vary between migratory phases (towards or away from the breeding ground), nor between the two sexes considered either overall or in the north or south migrations separately. These findings suggest that, if any social organization does exist, it is formed transiently when needed rather than being a constant feature of the population, and hence is more likely based on reciprocal altruism than kin selection.

Long-term effects of feeding during calfhood on subsequent performance in beef cattle (a review)

A review of the literature was undertaken to relate the fattening performance and the carcass quality traits in beef cattle to the feeding strategy applied during the first year of the calf's life. In all cases an early growth limitation causes major changes in body composition. Once allowed subsequently to recover on a liberal regime, the calves have a greater food dry matter intake and a greater food conversion efficiency than unrestricted calves. But contrary to that of animals restricted at a more advanced age, their potential for subsequent compensatory growth, particularly when restricted before weaning, is low and practically independent of the severity of the restriction. At slaughter at a fixed commercial carcass weight, the initial differences in body composition are generally no longer perceptible, thus suggesting that the feeding treatments during calfhood have no long-term effect on this parameter. It is concluded that there is no evidence that the composition of beef carcasses at slaughter can be manipulated at an early stage of development by means of feeding techniques.

Calf development and mother-calf spatial relationships in Southern right whales

Changes in spatial relationships between mother and calf right whales ( Eubalaena australis) from birth to the separation of yearling calves from their mothers were observed. During the first few weeks of a calf's life, mother and calf were within close proximity over 90% of the time, and mothers were responsible for maintenance of contact with their infants. Later calves strayed farther and initiated many more leaves and approaches than their quiescent mothers. The mothers still maintained contact with their infants. Just before migration away from the area, pair members resumed close proximity and leaves and approaches by both diminished. Yearling calves, returning to the area with their mothers after six months, stayed close to their mothers and few leaves and approaches by either pair member were recorded. The yearling calves were responsible for maintaining contact as the mothers left them more than approached them. This behaviour on the part of mothers probably contributed to weaning of yearlings and separation after a few weeks in the area.

Epidemiology of helminth infestation of beef cattle in central queensland.

SummaryThe results of epidemiological studies of helminths in young beef cattle in Central Queensland over a 2½‐year period commencing in January 1964 are reported.Studies were made on ten beef cattle properties, which have a total annual calf crop of approximately 2500 calves. Twenty‐five faecal samples were collected monthly at random from 30 to 40 permanently identified calves on each property, to determine the types and intensity of helminth infections.Although rainfall was well below average, infections with most of the helminth species commonly found in Queensland were detected. Increases in infection levels occurred, after rainfall of two inches or more, in animals up to 21 months of age. Only on a property where pastures were irrigated and the stocking rate was higher than normal for the area did a high percentage of calves show clinical symptoms of parasitic gastroenteritis. Haemonchus placet and Oesophagostomum radiatum were the predominant species. An immunity developed to O. radiatum during the first 12 to 15 months of the calf's life. The immunity to H. placet was variable with some animals susceptible to re‐infection up to 21 months of age.Recommendations for the control of helminths in beef cattle in this area are given.