The effects of twinning on mother—Offspring behavior in range beef cattle

Methods to increase the productivity of beef cattle include induced twinning and multiple fostering of calves on nurse cows, but little is known about the capacity of cows to rear more than one calf in a rangeland environment.Eight single and 14 twin calves and their mothers were studied in a 30.4-ha enclosure in a California rangeland environment from 2 to 20 weeks following parturition. Data were obtained on ingestive, grooming, agonistic, play and sexual behaviors, as well as spatial proximity of calves to mothers and peers.Initially, twins spent more time suckling their mothers than did single calves (presumably due to insufficient milk intake), but later adapted by utilizing natural forage and obtaining milk from alien cows. By 15–20 weeks of age, twins were suckling their dams for less than one-quarter of the time spent at 3–6 weeks, whereas the suckling time of single calves did not decline. Thus, twins may experience a natural early weaning from mother's milk.The hypothesis that mother—Offspring bonds are weaker with twins than with singles was supported by the fact that mothers bearing twins groomed their offspring less than mothers with singles, and twins were normally found at greater distances from their mothers than singles.Most long-distance cow—Calf separations resulted from the cow moving to feed or to obtain water. Reunion of mother and young depended on auditory communication; the calf normally traversed most of the intervening distance.     

Tympanic temperature in confined beef cattle exposed to excessive heat load

Angus crossbred yearling steers (n = 168) were used to evaluate effects on performance and tympanic temperature (TT) of feeding additional potassium and sodium to steers exposed to excessive heat load (maximum daily ambient temperature exceeded 32°C for three consecutive days) during seasonal summer conditions. Steers were assigned one of four treatments: (1) control; (2) potassium supplemented (diet containing 2.10% KHCO₃); (3) sodium supplemented (diet containing 1.10% NaCl); or (4) potassium and sodium supplemented (diet containing 2.10% KHCO₃ and 1.10% NaCl). Overall, additional KHCO₃ at the 2% level or NaCl at the 1% level did not improve performance or heat stress tolerance with these diet formulations. However, the addition of KHCO₃ did enhance water intake. Independent of treatment effects, TT of cattle displaying high, moderate, or low levels of stress suggest that cattle that do not adequately cool down at night are prone to achieving greater body temperatures during a subsequent hot day. Cattle that are prone to get hot but can cool at night can keep average tympanic temperatures at or near those of cattle that tend to consistently maintain lower peak and mean body temperatures. In addition, during cooler and moderately hot periods, cattle change TT in a stair-step or incremental pattern, while under hot conditions, average TT of group-fed cattle moves in conjunction with ambient conditions, indicating that thermoregulatory mechanisms are at or near maximum physiological capacity.     

The effects of blindfolding on behavior and heart rate in beef cattle during restraint

Use of a blindfold or hood during handling and restraint has been suggested for many wild and captive animals. Two experiments were conducted to determine the effects of blindfolds on beef cattle during restraint. In Experiment 1, 60 beef heifers, naı̈ve to the restraint facility, were randomly assigned to either visual restriction (blindfold) or no visual restriction (control) and tested daily during a 4-day trial to determine the effects during restraint. Heart rate (HR) was measured via telemetry, during a baseline period prior to treatment and continuously recorded during a 1-min period of restraint, which included some manipulation of the animal. Manipulation was initiated 15 s into the restraint period. Two persons simultaneously approached the animal one on either side, grasped the ears, and touched the neck, sides and rump to simulate normal management tasks. Electronic strain gauges attached to the head gate quantified the animal’s struggle during this procedure. These were used to determine the average and maximum exertion forces upon the head gate during restraint. The association between treatment, sample time (day 0–4), animal weight and the various outcome measures were analyzed using a generalized estimating equation method. Mean HR of heifers did not differ at the end of the treatment (95.04±4.66 bpm ) (P=0.64), but the HR tended to decrease more for blindfolded heifers compared to controls during restraint (average decrease 16.3±3.2 bpm and 14±2.9 bpm, respectively) (P=0.10). The average exertion forces applied by blindfolded heifers against the head gate were 23% lower (P<0.05) during the 1-min period and maximum forces were 28% lower (P<0.01). Heart rate and exertion forces declined over the 4 days for both treatment groups (P<0.001). In Experiment 2, 93 commercial beef calves (average age 92.9±2.0 days) were randomly assigned to either visual restriction (blindfold) (n=46) or no visual restriction (control) (n=47) treatments. Behavioral responses to treatment were quantified by measuring the amount of movement and recording the number of vocalizations while the calves were restrained for 1 min on a calf tilt table. Movement was recorded by an electronic device attached to a weighing platform that held the tilt table. After 30 s of restraint, one experimenter touched the animal’s ear while the other touched the neck, to simulate ear tagging and vaccination. Blindfolded calves moved 44% less than the control group (P<0.01). However, the number of vocalizations that occurred during the 1-min test period did not differ (P>0.05) between treatments. Overall, blindfolding cattle reduced the amount of struggle and tended to lower heart rate. Therefore, blindfolding may be advantageous during the routine invasive procedures commonly performed on cattle.     

The social environment influences the behavioural responses of beef cattle to handling

In cattle, a gregarious species, the social group influences individual stress responses to fear-eliciting situations. As handling can be stressful for farm animals, it can be hypothesised that social partners modify individual responses to handling. The present experiment investigated the effect of the presence or absence of social partners on behavioural reactions of beef calves in a handling test. At the age of 10 months, 38 calves from two breeds (Salers and Limousine) were individually subjected to the docility test, once while in visual contact with four familiar peers, and once in the absence of peers, following a crossover design. The docility test procedure included physical separation from peers (30 s; period 1), exposition to a stationary human (30 s; period 2), and handling by human (30 s-2.5 min, according to the success in handling; period 3). In absence of human (period 1), calves in visual contact with their peers spent more time motionless than when peers were totally absent (P<0.001). The social environment also influenced the duration of handling (period 3); the human required more time to successfully handle calves when peers were present (P<0.05). In conclusion, the presence of peers affects individual calves' reactions to the docility test.     

Evidence for maternal regulation of early conceptus growth and development in beef cattle

Fifty-one cyclic beef cows were mated with fertile bulls. At 36 h after the start of oestrus, cows were assigned to receive sesame oil (controls) or progesterone (100 mg) on Days 1, 2, 3 and 4 of pregnancy. Peripheral plasma concentration of progesterone was measured until slaughter on Days 5 or 14. Cows were randomly assigned to be slaughtered on Days 5 or 14 or remain intact and palpated per rectum on Day 40 to verify pregnancy. Uteri on Days 5 and 14 were flushed for recovery of luminal protein and conceptus tissue. Conceptus and endometrial tissues were cultured with [3H]leucine and submitted to two-dimensional-PAGE and fluorography. Administration of progesterone increased peripheral plasma progesterone concentration on Day 2-5. Conceptuses recovered from progesterone-treated cows on Day 14 were advanced in development compared to conceptuses from control cows. Conceptuses recovered from progesterone-treated cows were viable as polypeptides associated with maintenance of pregnancy in cattle were synthesized and released at an earlier time and pregnancy was maintained beyond Day 40. Early progesterone stimulation altered the synthesis and release of polypeptides from endometrial explant cultures on Day 5. Results indicate a role of progesterone in the maternal regulation of conceptus growth and development in early pregnancy of cattle.     

Maternal care and foal social relationships in a herd of Sorraia horses: Influence of maternal rank and experience

The influence of maternal rank and experience on patterns of maternal care and social relationships of foals were investigated in a managed herd of Sorraia horses, Equus caballus. Social interactions and spatial relationships of 13 foals (seven females and six males) born to seven mares were examined from birth to 10 months of life, within the three major periods of foal development. Conflict over suckling between dam and foal was not generally affected by rank and experience, but higher-ranking mothers allowed more suckling during late lactation than lower-ranking mothers. Foals of higher-ranking mares spent more time in proximity to the mother during socialization. Maternal rank and experience did not significantly affect maternal protectiveness, foal independence from the mother or the development of affiliative relationships between foals and group members. Foals of higher-ranking mares received lower frequencies of aggression from other horses only in the first month of life. Dominance relationships among foals depended mainly on aggressiveness and were not associated with maternal rank. The large variability in maternal behaviour, the absence of a significant association between maternal rank and body condition at parturition and the stable social environment within this herd may partly account for the reported results.     

Genetic aspects of twinning in cattle

Twinning in cattle ranges from about 1% for beef breeds to about 4% for dairy breeds. The incidence of double births may have both positive and negative effects, which mainly depends on the purpose for which the cattle are raised. Because of freemartinism, as well as management problems connected e.g. with a greater risk of dystocia and retained placenta, it is an undesirable trait in dairy herds. In beef cattle, however, twinning can considerably increase the efficiency of production. Low heritability, a long generation interval for progeny testing, sex-limited expression and an unfavourable correlation with milk yield make twinning difficult to control by selection. Hence, it is the type of trait for which the identification of the genetic marker - quantitative trait loci (QTL) linkage and the implementation of marker-assisted selection in breeding strategies are expected to be especially beneficial. Searching for QTL influencing the reproductive rate in cattle was performed mainly in the US Meat Animal Research Center twinning herd and in the commercial Norwegian cattle population. Among several genome regions that appear to control twinning and ovulation rates, the most interesting seem to be chromosomes 5, 7, 19 and 23.     

Evidence of genetic and maternal effects on secondary sex ratio in cattle

There is a paucity of estimates of genetic variation for secondary sex ratio (i.e., sex ratio at birth) in dairy cattle. The objective of this study was to estimate the direct and maternal genetic variance as well as maternal permanent environmental variance for offspring sex in dairy herds. The data consisted of 77,508 births from 61,963 dams and 2,859 sires in 1,369 Irish dairy herds across the years 2003 to 2008, inclusive. Mixed models were used to estimate all parameters. Significant genetic variation in sex ratio existed, with a heritability for secondary sex ratio estimated at 0.02; the genetic standard deviation was 0.07 percentage units. No maternal genetic effects on secondary sex ratio were identified but the proportion of phenotypic variance in secondary sex ratio attributable to maternal permanent environmental effects was similar to that attributable to the additive genetic variance (i.e., 0.02). These results, therefore, suggest that the paternal (genetic) influence on secondary sex ratio is just as large as the maternal (non-genetic) influence, both of which are biologically substantial. The results from this study will be useful in generating a sample population of divergent animals for inclusion in a controlled experiment to elucidate the physiological mechanism underpinning differences in secondary sex ratio.     

The effects of hair density of beef cattle on Haematobia irritans horn fly populations

Abstract We show the relationships that exist between the amount of hair and quantity of sebum on cattle skin and the population density of the horn fly, Haematobia irritans. Brahman and Chianina steers had means of 2390 and 1587 hairs per cm², respectively, significantly more than the mean number of hairs on Angus, Brahman x Angus Crossbred, Charolais, and Red Poll steers. The Chianina steers had > 30% more sebum present on their skin and hair (0.58g/929cm²) than the Angus, Charolais, and Red Poll steers at the Beef Cattle Research Station Savoy, Arkansas. The Brahman steers had a significantly greater amount of sebum present on the skin (1.51 g/ 929 cm²) than the Crossbred and purebred Angus steers (0.55 and 0.25g/929cm², respectively) at the South Central Family Farms Research Centre Booneville, Arkansas. The Brahman and Chianina steers had means of 61.9 and 17.0 horn flies per steer, respectively, during the fly season, whereas the Angus, Crossbred, Charolais and Red Poll steers had fly season means that ranged from 76.9 to 265.8 flies per steer. Regression analysis showed that an increase of 100 hairs per cm², was associated with a reduction of 11 horn flies in the Angus II, 5 in Angus I, 20 in Charolais, 37 in Red Poll, and 0.4 in Chianina steers at the Savoy Station and a reduction of 6.6 horn flies for the Angus, Brahman, and Crossbred steers at the Booneville Centre. Regardless of cattle breed, an increase of 1.0 g of sebum per 929 cm² output by the steer was associated with 478.5 additional hairs per cm² on the animal. Each increase of 0.25 g of sebum per 929 cm² resulted in a decrease of 9.2 horn flies per steer. We conclude that some of the factors responsible for fly-resistance in cattle are hair density and the corresponding amount of sebum present on cattle skin and hair.     

Effects of maternal nutrient restriction during early or mid-gestation without realimentation on maternal physiology and foetal growth and development in beef cattle

The aim of this study is to determine the effects of early and mid-gestation nutrient restriction on maternal metabolites and foetal growth. Primiparous Angus cows were synchronized and inseminated with semen from one sire. Dietary treatments were: control to gain 1 kg/week (CON) or 0.55% maintenance energy and CP requirements (nutrient restricted; NR). A subset of dams was fed NR (n=8) or CON (n=8) from days 30 to 110 of gestation. Another group was fed CON (n=8), days 30 to 190; NR (n=7), days 30 to 110 followed by CON days 110 to 190; or CON, (n=7) days 30 to 110 followed by NR days 110 to 190. Cows were harvested at days 110 or 190 of gestation, when foetal measurements and samples were collected. Cows that were NR during days 30 to 110 or 110 to 190 of gestation lost significant BW and body condition score (P<0.001), this was associated with reduced plasma glucose during NR (P<0.002). Foetal weights, empty foetal weights, abdominal and thoracic circumferences were all reduced (P<0.03) in day 110 NR animals. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.01) in NR day 110 female foetuses compared with CON foetus. Maternal serum triglycerides at day 110 of gestation were decreased (P<0.05) in NR dams, whereas foetal serum triglycerides were increased (P<0.05) in response to maternal NR. Foetal weights tended to be reduced (P=0.08) in NR/CON and CON/NR v. CON/CON cattle at day 190 of gestation. Empty foetal weights, abdominal and thoracic circumferences were reduced (P⩽0.03) in NR/CON and CON/NR v. CON/CON cattle. Brain weight as a percentage of empty foetal weight was increased (P<0.001) in NR/CON and CON/NR v. CON/CON cattle. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.003) in NR/CON and CON/NR v. CON/CON cattle. Maternal serum triglycerides at day 190 of gestation were decreased (P<0.05) in association with maternal NR. Foetal serum triglycerides at day 190 of gestation were increased (P<0.05) in response to maternal NR during early gestation but decreased by NR in mid gestation compared with CON foetuses. The data show that maternal nutrient restriction during early or mid-gestation cause’s asymmetrical foetal growth restriction, regardless if the restriction is preceded or followed by a period of non-restriction.     

The seasonal variation of thermophilic campylobacters in beef cattle, dairy cattle and calves

The epidemiology of clinical cases of campylobacter in temperate climates shows a striking seasonality. In the search for a seasonal environmental reservoir changes in the carriage rate and population size of campylobacters in bovine hosts with time have been measured. Most probable number (MPN) methodology was used to enumerate thermophilic campylobacters in samples taken from the small intestines of beef cattle at slaughter and the fresh faeces of four dairy herds and new-born calves. Statistical analyses revealed significant evidence for seasonal periodicity in the data from dairy herds ( P = 0·044). Not only was there a departure from constancy within a 12-month interval but these data revealed a true seasonality, that is, the same periodicity in numbers from one year to the next. Each herd had two peaks per year, in approximately spring and autumn. Peaks coincided in herds on neighbouring farms but those on farms in the north preceded those on farms in the south by 2 and 1 months, respectively ( P = 0·0057). Intestinal carriage by beef cattle at slaughter was 89·4% ( n = 360) with an average MPN campylobacters per gram fresh weight (MPN gfw⁻¹) of 6·1 × 10². Average MPN gfw⁻¹ in faeces from the dairy herds and calves were 69·9 ( S.D. 3) and 3·3 × 10⁴ ( S.D. 1·7 × 10²). There was no evidence of seasonal periodicity in the size of the campylobacter population in beef cattle at slaughter. Calves were campylobacter free at birth but became colonized within a few days.     

Observed frequency of monozygotic twinning in Holstein dairy cattle

Bonnier's equation is used to mathematically estimate the frequency of monozygotic (MZ) twinning in epidemiologic studies of twinning in dairy cattle; however, no empirical determination of MZ twinning has been reported in the literature. Our objectives were to empirically determine the frequency of MZ twinning in lactating Holstein cows and to compare this result with published estimates predicted using Bonnier's equation. Ear biopsies were collected from 107 sets of Holstein twins from six Wisconsin dairies resulting in 40 opposite-sex twins, 29 same-sex male twins, and 38 same-sex female twins. To empirically determine the frequency of MZ twinning, DNA extracted from ear biopsies collected from the 67 same-sex twins was PCR amplified using primers for a minimum of 5 polymorphic microsatellite DNA markers. Opposite-sex twins were classified as dizygotic (DZ) as well as same-sex twins differing in at least one microsatellite DNA marker. Same-sex twins were classified as MZ when all genotypes for a minimum of five markers were identical. Of the 67 same-sex twins, 62 were classified as DZ and 5 MZ resulting in a MZ twinning frequency of 7.5% of same-sex twins and 4.7% of all twins. The estimated frequency of MZ twinning in this population of twin calves using Bonnier's equation was 39.5% of same-sex twins and 24.7% of all twins. We concluded that MZ twinning occurred infrequently in Holstein cattle and perhaps less frequently than that reported in studies using Bonnier's equation to estimate MZ twinning.     

Low twinning rate and seasonal effects on twinning in a fertile population,the Hutterites

This paper analyzes from the mid 18th century to 1987 the birth records of the Dariusleut, one of the three subgroups of the Hutterite population. The aim of this study is to describe several aspects of the twinning rate in a fertile population. The overall rate of twinning was 0.90%:103 twins among all 11492 maternities. The rate peaked at the 7th birth order and at the maternal age of 40 years and over. Until the mid 19th century when the Hutterites lived in Russia, the twinning rate was higher (1.5%), and it decreased during the migration period in the second half of the 19th century (0.7%). After the group had settled in the USA and Canada, the population maintained a twinning rate of 1.0% until 1965. After 1965 the rate decreased to 0.7%, partly due to a decline in fertility among women aged 30 years and over. There was a significant seasonal variation: the twinning rate decreased to 0.5% in May–July compared to 1.2% for the other three seasons during the years up to 1965 (P<0.01), while more recent mothers did not show such a seasonal variation. The incidence of twin births in this population seems to have been influenced by environmental factors, which would change their effect seasonally and secularly.     

The risk of Listeria monocytogenes infection in beef cattle operations

Aim:  To determine the prevalence of Listeria monocytogenes and associated risk factors among beef operations (cow-calf and feedlot) in central and southern California.
Methods and Results:  A repeated cross-sectional study where faecal and environmental samples were collected from 50 operations three times a year at different seasons was carried out. Samples were tested for presence of L. monocytogenes using a combination of enrichment and polymerase chain reaction tests. Data on putative risk factors were also collected. Listeria monocytogenes was detected in faecal samples from cows, calves and other animals on calf-cow operations at proportions of 3·1%, 3·75% and 2·5%, respectively. The organism was detected in 5·3% of cut-grass, 5·3% of soil, 14·3% of irrigation ditches, 3·1% of the ponds and 6·5% of water troughs samples. Listeria monocytogenes was less common in faecal (0·3%) and soil (0·75%) samples collected from feedlots.
Conclusions:  Listeria monocytogenes was present at a higher proportion among cow-calf operations than feedlots. There was no significant seasonal variation in the occurrence of this pathogen within the two types of operations.
Significance and Impact of the Study:  If risk mitigation strategies were implemented to reduce the public health risk these should focus in cow-calf operations.