Presence Of Calves Research Articles

Comportamento de vacas mestiças ordenhadas na presença ou na ausência de suas crias

The behavior of crossbreed cows, milked in the presence or absence of their calves, was analyzed. The trial was conducted on the Dairy Cattle Sector of UESB School of Animal Science in Itapetinga BA Brazil. Twenty crossbreedHolsteinx Gir cows were distributed in a randomized block design with 10 replications for each treatment for the experimental period of 31 days, during lactation. Results were analyzed by nonparametric chi-square test at 5% significance, except the variables time at the milking sector and milk production which were evaluated by analysis of variance and F test at 5% probability. Although cows with the presence of calves during milking had higher reactivity, behavioral activities and more time in the milking sector, milk production was not affected.

Bovine Viral Diarrhea Virus Infections

Bovine viral diarrhea virus (BVDV) continues to be of economic significance to the livestock industry in terms of acute disease and fetal loss. Many of the lesions relating to BVDV infection have been well described previously. The virus is perpetuated in herds through the presence of calves that are persistently infected. Relationships between various species and biotypes of BVDV and host defenses are increasingly understood. Understanding of the host defense mechanisms of innate immunity and adaptive immunity continues to improve, and the effects of the virus on these immune mechanisms are being used to explain how persistent infection develops. The noncytopathic biotype of BVDV plays the major role in its effects on the host defenses by inhibiting various aspects of the innate immune system and creation of immunotolerance in the fetus during early gestation. Recent advances have allowed for development of affordable test strategies to identify and remove persistently infected animals. With these improved tests and removal strategies, the livestock industry can begin more widespread effective control programs.

Coordinated feeding behavior of the Guiana dolphin, Sotalia guianensis (Cetacea: Delphinidae), in southeastern Brazil: a comparison between populations

The coordinated feeding tactics used by delphinids are influenced by differences in the distribution of prey species, season, and opportunities for social learning. In the present study, we compared the coordinated feeding behavior of two populations of the Guiana dolphin, Sotalia guianensis, in southeastern Brazil, and how these feeding tactics vary seasonality and in the presence of calves. We observed eight types of coordinated feeding tactics, which differed in frequency and in the mean number of individuals engaged in them, and between both areas. Feeding tactics used to herd and capture prey were the most frequent and engaged a greater number of individuals, suggesting that these tactics are better for capturing fish that gather in larger schools. Furthermore, the seasons influenced the occurrence of different prey items, which in turn modified the feeding tactics of the dolphins. In the Ilha Grande Bay we observed that bouts lasted longer and larger groups engaged in the feeding tactics, which may be associated with the seasonal spawning of larger schooling fish such as Sardinella brasiliensis (Steindachner, 1879) (Teleostei: Clupeidae). However, in the Sepetiba Bay, we observed longer feeding bouts and a smaller number of individuals engaged in the feeding tactics during autumn-winter. This may be associated with the fact that the most abundant prey species, Micropogonias furnieri (Desmarest, 1823) (Teleostei: Sciaenidae), gathers in small schools. Calves were present in 95% of all coordinated feeding tactics that occurred in the Ilha Grande Bay and in approximately 61% of feeding tactics in the Sepetiba Bay, suggesting that these areas are important for social learning. This study provides more information about feeding tactics and improves knowledge of the coordinated behavior of Sotalia guianensis (Van Beneden, 1864).

Ocitocina exógena e a presença do bezerro sobre a produção e qualidade do leite de vacas mestiças

Milk yield and milk quality were evaluated in ½ holstein/zebu cows, with or without the calf presence or oxytocin injection. It was used eight ½ holstein/zebu cows, multiparous, distributed in two Latin squares (4x4) in factorial scheme (2x2), with or without calf presence, and whith or without oxytocin injection. The milk was analyzed for somatic cells count (SCC), total bacterial count (TBC/mL), lactose, total fat, protein, total solids, and no fat dry matter concentration. The animals milked with calves and with ocytocin injection showed a higher milk production. There was no interaction between the effects, and any one of the methods may used for stimulation of aveolar contraction. The calf presence and oxytocin injection during milking results in higher milk production, but no changes in milk quality and composition of ½ holstein/zebu cows.

Photo-Identification Methods Reveal Seasonal and Long-Term Site-Fidelity of Risso’s Dolphins (<i>Grampus griseus</i>) in Shallow Waters (Cardigan Bay, Wales)

A photo-identification study on Risso’s dolphins was carried out off Bardsey Island in Wales (July to September, 1997-2007). Their local abundance was estimated using two different analytical techniques: 1) mark-recapture of well-marked dolphins using a “closed-population” model; and 2) a census technique based on the total number of identified individual dolphins sighted over the study period. The mark-recapture estimates of 121 (left sides; 64 - 178, 95% CI; CV 0.24) and 145 dolphins (right sides; 78 - 213, 95% CI; CV 0.24) closely matched the census technique estimates (population size of 90 - 151). It was found that the dolphins showed a degree of long-term and seasonal site-fidelity. A first long-distance match was made for Risso’s dolphins (319 km) between Bardsey Island and Cornwall, confirming they can be wide-ranging animals. This study demonstrates that the combination of systematic and opportunistic photo-ID studies has complementary value as a population assessment tool in generating the first local abundance estimate for Risso’s dolphins in UK waters. From the conservation perspective, these studies confirm the regular presence of Risso’s dolphins in these waters and the presence of calves shows breeding. Bardsey Island may be part of a network of localities that are important habitats to this species where it may take advantage of prey abundance in shallow waters. As such, results of this study may provide assistance to include the Risso’s dolphin in future regional conservation strategies including the envisaged marine protected areas.

Influence of calf presence during milking on yield, composition, fatty acid profile and lipolytic system of milk in Prim’Holstein and Salers cow breeds

Milk fat content and its fatty acid (FA) profile are important components of both the milk nutritional and technological qualities. The present study was conducted to evaluate the influence of calf presence during milking and of cow breed on milk yield, gross composition, FA profile and milk lipolytic system. A total of 30 Prim’Holstein (PH) and Salers (S) primiparous lactating cows were milked in the presence or absence of their calves during 210 days of lactation and bulk milks were collected during 6 weeks in a restricted part of the whole experimental period for analyses. Calf presence increased milk yield and decreased the milk fat content in S cows, whereas no difference was observed for the PH cows. The PH milk had higher levels of short- and medium-chain FA and C18:2 n−6, whereas S milk had higher levels of C18:2 cis-9,trans-11 (conjugated linoleic acid, CLA), C18:3 n−3 and C20:5 n−3. The S milk also had higher initial lipolysis. Calf presence during milking increased the C16:0 percentage and decreased C18:0, C18:2 n−6, C18:3 n−3, total polyunsaturated FA percentages in milk fat. Calf presence decreased the milk trans-C18:1 level only in S cows. Cis-9,trans-11-CLA level increased in the calf presence in PH cows, whereas it decreased in S cows. Calf presence during milking increased milk lipolysis after 24 h only in the PH cows. Calf presence during milking had significant effects on the milk yield, gross and fine composition, and lipolysis but these effects differed according to the breed.

Moose (Alces alces) calf survival rates in the presence of wolves (Canis lupus) in southeast Norway

Wolves (Canis lupus) are recolonizing Scandinavia and becoming a new limiting factor that should be taken into account in the management of moose (Alces alces). However, there is a lack of empirical estimates of moose survival after wolf recolonization. We investigated the effects of wolf abundance, moose litter size (single/twin calves), and climatic factors on annual and seasonal calf survival rates in a moose population in southeast Norway. We used data that were obtained over 7 years by radio-tracking and regular visual observations of 68 moose cows to determine the presence or absence of calves at heel. Annual and winter calf survival rates were 20–40 percentage points lower in the wolf territory compared with previous estimates of moose calf survival in similar areas that lacked wolves. Cause-specific studies of mortality would further enhance our ability to determine the relative role of various limiting factors. Our study suggests that moose managers should regulate quotas to buffer the lower survival rates after wolf recolonization.

Effect of calf presence during milking on milk fatty acid profile in Prim'Holstein and Salers cow breeds.

The present study was conducted in order to evaluate the effects of calf presence during milking and cow breed on milk fatty acid (FA) profile. 30 Prim’Holstein (H) and Salers (S) primiparous lactating cows were milked in the presence (CP) or in the absence (CA) of their calves, during the 9 months of lactation. Milk FA profile was significantly influenced by breed: 4:0, 12:0, 18:2 n-6 and cis-18:1 had higher concentrations in milk from H cows, whereas 14:0, 18:3 n-3, cis-9,trans-11-CLA and trans-18:1 had higher concentrations in milk from S cows. The presence of the calf during milking also had an important effect: it decreased the milk fat content, as well as 18:0, 18:2 n-6, 18:3 n-3 and trans-18:1 levels and it increased 16:0 level. Cis-9,trans-11-CLA concentration increased in the presence of the calf, for H cows, whereas it decreased for S cows.

Effect of Calf Presence During Milking on Milk Fatty Acid Profile in Prim’Holstein and Salers Cow Breeds

The present study was conducted in order to evaluate the effects of calf presence during milking and cow breed on milk fatty acid (FA) profile. 30 Prim’Holstein (H) and Salers (S) primiparous lactating cows were milked in the presence (CP) or in the absence (CA) of their calves, during the 9 months of lactation. Milk FA profile was significantly influenced by breed: 4:0, 12:0, 18:2 n-6 and cis-18:1 had higher concentrations in milk from H cows, whereas 14:0, 18:3 n-3, cis-9,trans-11-CLA and trans-18:1 had higher concentrations in milk from S cows. The presence of the calf during milking also had an important effect: it decreased the milk fat content, as well as 18:0, 18:2 n-6, 18:3 n-3 and trans-18:1 levels and it increased 16:0 level. Cis-9,trans-11-CLA concentration increased in the presence of the calf, for H cows, whereas it decreased for S cows.

Coordinated feeding tactics of the Guiana dolphin, Sotalia guianensis (Cetacea: Delphinidae), in Ilha Grande Bay, Rio de Janeiro, Brazil

Differences in distribution, prey species, season and social learning opportunities influence the feeding tactics used by marine mammals. Here, we analyze the coordinated feeding behavior of the Guiana dolphin, Sotalia guianensis (Van Bénéden, 1864, Delphinidae) and its relation to seasonality and the presence of calves. In a total of 201 feeding bouts, we observed four types of coordinated feeding tactics, which differed in frequency and in mean number of engaged individuals. Tactics in which dolphins used their bodies to herd and capture prey were the most frequent, presenting a higher frequency and engaging a higher number of individuals, suggesting that these tactics are better for capturing fishes which form larger schools. Furthermore, the seasons influenced the feeding behavior used by dolphins. During spring-summer, a longer duration of bouts and a larger number of individuals engaged in the feeding tactics was observed, which may be related to the seasonal spawning of larger schooling fish, such as Sardinella brasiliensis (Steindachner, 1879). Calves were present in 95% of all coordinated feeding tactic occurrences. This study indicates a complete preference of dolphins for coordinating their actions to capture prey and for the first time reports the presence of calves in the coordinated tactics and jumps. This broadens the current knowledge of the Guiana dolphin feeding tactics.

Factors determining whistle emission rate in bottlenose dolphins of Bocas del Toro, Panama.

Dolphins of Bocas del Toro are known to change their communication signals when interacting with dolphin‐watching boats. In this study we examine the role of engine noise, calf presence, and behavior on the emission rate of whistles. Whistle emission rate was measured in groups where calves were and were not present and while interacting and not interacting with boats. A general higher whistle emission rate was shown when only the research boat was present and during social events, although whistle contours were not significantly different. Whistle rate was also slightly higher in groups with calves, particularly during social events. While in the presence of other boats, whistle emissions were higher during traveling events. A low whistle emission in the presence of other boats than the research boat (largely dolphin‐watching boats) may be the result of masking or a response to the engine noise during these encounters. In addition, groups with calves may be avoiding intrusive dolphin‐watching boats. Most groups with calves, for which whistle emission was higher during social events, were observed during encounters with the research boat (engine off). These results provide insights on some of the environmental and biological factors that may be influencing dolphin whistle emission.

Sightings of the bottlenose dolphins ( Tursiops truncatus) in the Trindade Island, Brazil, South Atlantic Ocean

The present work brings information about the first sightings of the bottlenose dolphin, Tursiops truncatus, in the oceanic island of Trindade, 1140 km off the Brazilian coast. Nine days of opportunistic boat surveys were performed between December 2009 and March 2010, totalling 54 hours of sampling effort. Three sightings were obtained of the bottlenose dolphin, varying from 1 single animal to a group with 10 dolphins, including calves. One group was observed and filmed underwater. Sighting depth varied from 5 to 35 m and distance from the coast was registered between 70 to 300 m. Comparing our results with other studies in the Brazilian oceanic islands shows similarities in the location of the sightings as well the reported group size and the presence of calves suggesting that bottlenose dolphins may be using these environments to socialize and take care of the young dolphins. Because the oceanic islands constitute fragile and isolated ecosystems it is crucial to have a better understanding of the conservation of their marine life, including top predator animals such as the bottlenose dolphins.

Ecology and behavior of the estuarine dolphin, Sotalia guianensis (Cetacea: Delphinidae), in Sepetiba Bay, South-eastern Brazil

The dynamics of habitat utilization by Sotalia guianensis has been investigated. Between January 1997 and May 1998, 145 h of direct observations were made from a fixed location at Ponta do Zumbi on Marambaia Island, and 249 groups of dolphins were sighted. Initial and final times of the observation, approximate location, presence of calves, activities performed by the dolphins and prevailing weather conditions were recorded for all sightings. Dolphin groups were observed during all seasons of the year, and sightings occurred mainly during the late morning (9:00 - 11:59 h) and early afternoon (12:00 - 14:59 h). Dolphins exhibited a preference for the sheltered sub-areas of the bay rather than for the sub-area adjacent to the open sea. The most commonly observed aggregation of animals consisted of groups of 1 – 10 individuals. The activities performed by the dolphins were, in decreasing order of frequency of occurrence: foraging/feeding, travelling, socialization and resting. Daily and seasonal profiles of dolphins activities were dictated by many interacting factors (temporal, environmental and population characteristics), none of which could alone explain the manner in which the animals utilize the area or the organization of life cycle in the habitat. Key words: Sotalia guianensis, habitat use, behaviour, group size.

Field Study

Bovine viral diarrhea virus (BVDV) is a major pathogen involved in the bovine respiratory disease complex (BRD). Immunosuppression induced by BVDV is thought to contribute to BRD, exacerbating secondary bacterial and viral pneumonias. Calves persistently infected (PI) with BVDV maintain the virus in the cattle population and serve as the primary source of transmission within and between herds. The impact that PI calves have on overall feedlot calf health and performance has been shown to be significant. In this field study, calves from one farm, but from different BVDV exposure backgrounds, were monitored after entry into a feedlot in which constant exposure to BVDV virus occurred via presence of PI calves. The objective was to determine if different pre-weaning BVDV exposures mitigated adverse consequences of constant BVDV exposure in a feedlot setting.

Lack of evidence for fecal shedding of Mycobacterium avium subsp. paratuberculosis in calves born to fecal culture positive dams

The objective was to detect presence of calves excreting Mycobacterium avium subsp. paratuberculosis (MAP) in their feces as a consequence of being born to MAP fecal culture positive (vs. negative) dams. For each cow that was about to calf, approximately 10 g of feces was collected manually by the herdsmen from the rectum using a disposable plastic examination sleeve within 48–72 h prior to actual calving. Between 1 and 3 d of birth, herd personnel collected approximately 10 g of fecal samples followed by monthly visits to the farm at which time 10 g of fecal samples were again collected by study investigators from each calf at approximately 30, 60 and 90 d of age. Mycobacterium avium subsp. paratuberculosis was recovered from 8% (5/60) of the cows that gave birth to calves. However, MAP was not recovered from any of the fecal samples (0/240) collected from study calves. Findings of the present study suggest lack of evidence for fecal excretion of MAP in calves born to fecal culture positive (vs. negative) dams in a heavily infected herd.

Residency Patterns, Abundance, and Social Composition of Bottlenose Dolphins (<I>Tursiops truncatus</I>) in Bahía San Antonio, Patagonia, Argentina

Residency patterns, abundance, and social composition of bottlenose dolphins (Tursiops truncatus) were assessed from 2006 to 2008 in Bahia San Antonio (BSA), Patagonia, Argentina. A total of 714 survey hours resulted in 132 contact hours with 224 bottlenose dolphin groups. Results indicated that dolphins can be seen year-round on average every 4 h, with sighting periods lasting an average of 45 min. A total of 57 bottlenose dolphins were positively identified in the bay, of which 56% showed a degree of residency, including almost all mother and calf pairs. Using the closed time heterogeneity model (Mth), and accounting for the proportion of unidentifiable individuals, calculations resulted in a corrected abundance estimate of 83 individuals for the study area. Further analysis revealed that individual dolphins associated at random and that the entire community exhibits rapid disassociations and two levels of casual acquaintances. Data suggest that the shallow waters of BSA support a relatively resident community of bottlenose dolphins, living in a fission-fusion society in which companionships frequently change. The relative constant presence of calves in more than 50% of the dolphin groups and the observed presence of neonates might furthermore indicate that dolphins specifically use this area, among others, to give birth and nurse their young. In addition, a reported decline in bottlenose dolphin sightings in the larger area of the Argentinean coast might indicate that BSA is one of the last remaining refuges of the species in the country. Further research seems vital for their conservation.

Manatee (Trichechus manatus) vocalization usage in relation to environmental noise levels

Noise can interfere with acoustic communication by masking signals that contain biologically important information. Communication theory recognizes several ways a sender can modify its acoustic signal to compensate for noise, including increasing the source level of a signal, its repetition, its duration, shifting frequency outside that of the noise band, or shifting the timing of signal emission outside of noise periods. The extent to which animals would be expected to use these compensation mechanisms depends on the benefit of successful communication, risk of failure, and the cost of compensation. Here we study whether a coastal marine mammal, the manatee, can modify vocalizations as a function of behavioral context and ambient noise level. To investigate whether and how manatees modify their vocalizations, natural vocalization usage and structure were examined in terms of vocalization rate, duration, frequency, and source level. Vocalizations were classified into two call types, chirps and squeaks, which were analyzed independently. In conditions of elevated noise levels, call rates decreased during feeding and social behaviors, and the duration of each call type was differently influenced by the presence of calves. These results suggest that ambient noise levels do have a detectable effect on manatee communication and that manatees modify their vocalizations as a function of noise in specific behavioral contexts.

Performance and nursing behaviour of beef cows with different types of calf management

The aim of this experiment was to evaluate the effect of calf management during lactation on dam performance and nursing behaviour. Thirty-six multiparous beef cows (aged 7.5 ± 0.52 years) of Parda de Montaña breed (mean live-weight (LW) at calving 566 ± 9.3 kg) with a moderate body condition (mean 2.6 ± 0.02 on a 1 to 5 scale), were assigned to three nursing frequencies from the day after parturition: Once-daily restricted nursing during a 30 min period at 0800 h (RESTR1), twice-daily restricted nursing during two 30 min periods at 0800 and 1530 h (RESTR2) and ad libitum nursing (ADLIB). Cows were fed throughout the experiment 80 MJ/day of metabolizable energy. Cow–calf behaviour recordings were performed on days 30 and 66 of lactation in each treatment. Blood samples were collected fortnightly to analyse non-esterified fatty acids (NEFA) by an enzymatic colorimetric method, and twice weekly to determine progesterone concentrations by radioimmunoassay. Cow LW losses (P < 0.05), fat-corrected milk yield (P < 0.05) and calf average daily gain (P < 0.01) during lactation were higher in ADLIB. Nursing frequency affected the mean serum concentrations of NEFA, being lower in RESTR1 (0.18 mmol/l; P < 0.05) than in RESTR2 and ADLIB cows (0.29 and 0.25 mmol/l, respectively). The highest occurrence of nursing bouts was observed in ADLIB, leading to greater nursing duration per day (not statistically compared) in this treatment (58.8 ± 5.84 min) than in their restricted nursing counterparts (22.2 ± 1.42 and 34.3 ± 1.16 min, in RESTR1 and RESTR2, respectively). The nursing system did not affect the proportion of cows cycling within 3 months post partum (58%, 46% and 55% in RESTR1, RESTR2 and ADLIB, respectively; P > 0.05). The majority of cows in all treatments showed a short oestrus cycle after first ovulation (75%, 100% and 83%; P > 0.05). In conclusion, the post-partum luteal function in cows managed under continuous access to calves was similar to restricted nursing frequencies, despite the greater suckling intensity of the formers. Restricting calf presence does not enhance the resumption of ovarian activity when suckler cows are managed in moderate nutritional conditions.

What can we learn from studying manatee vocalization patterns?

Vocalizations are assumed to form the basis of most long range communication in manatees, so studying how animals naturally use their vocalizations can provide insight into many aspects of the manatee acoustic communication system. Vocalizations were recorded from manatees in Sarasota Bay, FL over two nonwinter seasons. Recordings were made under a variety of conditions spanning different habitats, social groupings, behavioral states, environmental sound levels, and observation methods. Analysis of vocalization patterns indicates that manatee vocalization usage is highly context dependent. Patterns were observed to be a function of calf presence, behavioral state, and environmental sound levels. Additionally, vocalizations tended to separate into two distinct call types. Observed patterns will be discussed in the context of communication theory. Further analysis of the dataset has the potential to offer information relating to signal evolution, call function, and impacts of noise on manatee communication ...

Efficacy of metaphylactic florfenicol therapy during natural outbreaks of bovine respiratory disease

The efficacy of an injectable formulation of florfenicol (300 mg/mL) as metaphylactic control of naturally occurring bovine respiratory disease (BRD) was evaluated in two double-blind randomly controlled field studies on two Dutch veal calf herds (A and B). Cattle aged not older than 3 months and in the direct presence of calves with clinical respiratory disease were randomly allocated to treatment with 40 mg/kg florfenicol subcutaneously (s.c.) a positive control treatment (12.5 mg/kg tilmicosin p.o. twice daily for five consecutive days in herd A, and 12.5 mg/kg doxycycline p.o. twice daily for five consecutive days in herd B), or a negative control (one placebo saline s.c. administration on D0). The predominant respiratory pathogens present in pretreatment respiratory samples from affected animals were Mycoplasma bovis and Pasteurella multocida in outbreaks A and B, respectively. Metaphylactic administration of florfenicol resulted in a statistically significant weight gain, decreased rectal temperature for five consecutive days after treatment and decreased metaphylactic failure percentages compared with both positive and negative control groups. In summary, these studies demonstrated that a single s.c. injection of florfenicol is effective and practical for control of the bacterial component of BRD in veal calves.