Effects of breed, age of dam, birth year, birth season and sex on weaning weight of beef calves

Weaning weights of 442 beef calves (223 male and 219 female), born between 1997 and 2004 from cows of nine breeds (Hungarian Fleckvieh, Hereford, Aberdeen Angus, Red Angus, Lincoln Red, Charolais, Limousin, Blonde d' Aquitaine and Shaver) and maintained in the same conditions on peat-bog soil pasture at Keszthely, were evaluated. The effect of breed, age of dam, year/season of birth and sex of calf on the 205-day weaning weight was computed by analysis of variance (GLM). Overall mean of the 205-day weaning weight of all calves was 193 kg. The contribution to the total phenotypic variance of the 205-day weaning weight was: 18.60% by breed, 2.79% by age of dam, 43.23% by birth year, 3.95% by birth season and 31.43% by sex of calf. The evaluated factors had a significant (P < 0.05) effect on 205-day weight. Mean values by breeds were 198, 163, 206, 205, 182, 204, 181, 189 and 204 kg, respectively. According to the age of the dam, the weaning weight increased up to 5 years and after the maximum (205 kg) decreased. The minimum values were found in the group of 2- (178 kg) and 12-year-old (174 kg) cows. With respect to birth year, the highest weaning weight (238 kg) was observed in 2002 and the lowest (151 kg) in 1999. For birth season, winter, spring, summer and autumn, the 205-day weaning weight was 183, 196, 203 and 190 kg, respectively. Male calves reached 202 kg and female calves 185 kg mean value of the adjusted weaning weight.     

Diagnosis of copper deficiency and effects of supplementation in beef cows.

The effects of feeding supplementary dietary copper to a herd of 400 beef cows, were studied over a two year period. In the first year of the trial, the calves showed clinical signs of copper deficiency. There was improved growth following subcutaneous injection of copper ethylenediamine tetraacetate, and the treated calves had a 2.8% increase in adjusted weaning weights. In the second year of the trial pregnant cows were fed a basal ration of bromegrass silage, barley and minerals over the winter feeding period. The feed was supplemented with copper so that half received 5.5 mg/kg of copper on a dry matter basis and half 40 mg/kg. Calving occurred in the spring and half the calves were treated with injectable copper at birth and again at 12 weeks of age. There was no evidence of copper deficiency in the calves and there was no effect of high level copper supplementation on calf birth weight, or neutrophil candidacidal activity. Susceptibility to diarrhea varied in a complex fashion; morbidity was lowest in calves born to dams fed supplementary copper and highest in calves born to supplemented dams and injected with copper at birth. The cows and calves grazed the same copper deficient pasture over the summer. The average daily gain for calves born to supplemented cows was 0.999 +/- 0.010 kg/day (x +/- SEM) which was significantly greater than the 0.972 +/- 0.009 kg/day for calves from nonsupplemented dams (p = 0.044). The benefit of copper supplementation on 200 day weaning weight was estimated at 4.8 kg. Evidence of copper deficiency was seen when a herd test showed mean serum levels below 9 mumol/L and liver values below 0.09 mmol/kg wet matter.     

Hematologic values in calves during the first 6 months of life

BACKGROUND: Age-related changes in hematologic values are known to occur in many species. Few published studies include repeated measurements of hematologic parameters in calves during the first months of life. OBJECTIVE: The aim of the present study was to monitor hematologic values by sequential measurements from birth to 6 months of age in 15 healthy calves of the Norwegian Red breed, and compare the results to reference intervals for adult, lactating dairy cows. METHODS: Fifteen clinically healthy calves were sampled every week during the first 5 weeks of life and every month thereafter until 6 months of age. Hematologic values were measured using the ADVIA 120 hematology system. Reference intervals were determined for 75 healthy adult cows of the same breed. RESULTS: Compared with adult reference intervals, the MCV was lower and the RBC count was higher in calves throughout the investigation period. Hemoglobin concentration stayed largely within the adult reference interval. Mean MCHC was lower than adult values for 5 weeks, then increased and reached adult values by weeks 10-12. The mean lymphocyte count for calves reached adult reference values at weeks 6-8, and the mean monocyte count increased steadily until weeks 14-16. For most leukocytes, interindividual variation was larger during the first 5-8 weeks of life. The mean platelet count for calves was higher than the adult reference interval until weeks 19-21 of age. CONCLUSIONS: Age-specific reference intervals for calves from birth to 6 month of age are needed for RBC count, MCV, MCHC, red cell distribution width, and platelet and lymphocyte counts.     

Cow breeding and calf growth performance as affected by pregnancy status the previous year

A 2-yr study was conducted to compare the subsequent cow breeding and calf performance of cows that were nonpregnant with cows that were pregnant at the time calves were weaned. Cows were Angus (A), Polled Hereford (PH), Santa Gertrudis (SG) straightbreds and crossbreds of these breeds. Nonpregnant cows (G1) were 4- to 9-yr-olds that had a calf the previous year and appeared to be physically sound with no detection (by rectal palpation) of an abnormal reproductive tract due to disease, abnormal growth or calving difficulties. Pregnant cows (G2) were of similar age and breed composition to G1 cows. The 93 G1 and the 193 G2 cows were assigned within age and breed composition to sire breeding groups on pasture in an approximate 1:2 ratio, respectively, per sire. There were six A, three PH and one SG sires. The year prior to G1 cows being nonpregnant, G1 cows calved 11 d later (P less than .01) than G2 cows. Subsequent to their being nonpregnant, G1 cows gained 27 kg more (P less than .001) weight during the breeding period, had 5.4 percentage units more (P less than .29) calves born, had calves 17 d earlier (P less than .001) in the calving period, had calves that gained at a similar rate to weaning and had calves that were 14 kg heavier (P less than .01) at weaning (due to their being 17 d older) compared with G2 cows and calves.     

Increased calf production in cattle selected for twin ovulations

The effects of increasing fetal numbers and their distribution between the left and right uterine horns on calf survival, calf BW at birth and weaning, gestation length, dystocia, and calf sex ratio were evaluated for single (n = 1,587), twin (n = 2,440), and triplet calves (n = 147) born to primiparous and multiparous females in the Twinner population at the US Meat Animal Research Center between 1994 and 2004. Cattle were distributed equally between the spring and fall breeding seasons. Fetal number and distribution in utero were determined by real-time ultrasonography at 40 to 70 d postbreeding. For cows and heifers combined, number of calves per parturition increased from 1.34 in 1994 to 1.56 in 2004. Gestation length was 6.8 d shorter (P < 0.01) for twins compared with singles (277.5 +/- 0.2 vs. 284.3 +/- 0.2 d) and 12.7 d shorter for triplets (271.6 +/- 0.8 d). Survival and BW of individual calves at birth decreased (P < 0.01) but total calf BW per dam increased (P < 0.01) as fetal number increased from single to triplet births. Twins resulting from bilateral twin ovulations had increased (P < 0.01) survival and BW at birth, a longer (P < 0.01) gestation length, and less (P < 0.01) dystocia than twins resulting from unilateral twin ovulations. Calf survival and BW at birth were 97.2 +/- 0.3% and 48.0 +/- 0.1 kg for singles, 92.0 +/- 0.4% and 39.0 +/- 0.2 kg for bilateral twins, 83.2 +/- 0.4% and 36.7 +/- 0.2 kg for unilateral twins, 73.8 +/- 1.4% and 30.6 +/- 0.7 kg for bilateral triplets, and 51.9 +/- 3.2% and 31.7 +/- 1.6 kg for unilateral triplets. Birth weight of single calves increased by 0.51 kg/d for each additional day of gestation length vs. 0.38 kg/d for individual twins. Calf BW at birth increased (P < 0.01) with age of dam from 2 to 4 yr. Twin and triplet births had a greater (P < 0.01) incidence of dystocia than single births. The ratio of male:female calves (0.52:0.48) at birth was not affected by type of birth. Postnatal calf survival was similar for all 3 types of birth. Total progeny BW at weaning for single, twin, and triplet births was 217.7 +/- 2.5, 328.3 +/- 3.2, and 378.4 +/- 15.0 kg, respectively (P < 0.01). Although most bovine females have the uterine capacity to gestate twin calves, decreased survival and BW of unilateral twins and of all triplets indicate that their growth and development may have been compromised by uterine crowding.     

Risk factors associated with a skewed natal sex ratio in captive black rhinoceroses (Diceros bicornis) in the United States.

The skew toward males in the sex ratio of calves is considered to be a problem for the captive population of black rhinoceroses (Diceros bicornis) in North America. This study used a retrospective case-control design to determine whether there was a predisposition toward birth of male calves over female calves and to examine risk factors associated with the occurrence of any detected skewed natal sex ratio in captive black rhinoceroses in the United States. The study population included captive female black rhinoceroses housed in the United States that had given birth to at least one calf of known sex. This study confirmed a skewing of the natal sex ratio toward male calves in the captive black rhinoceros population. The skewed ratio was found in calves born to wild-born dams, for which an increased time in captivity, irrespective of age, was associated with an increased likelihood of a male calf. Dams between 12 and 19 yr of age had a decreased likelihood of a male calf. The data also suggested a possible trend for the southern subspecies of black rhinoceros (Diceros bicornis minor) to be more likely to produce male calves than the eastern subspecies (Diceros bicornis michaeli). No associations were found with the sex of offspring in captive-born dams: however, this lack of association could be a result of low power in the study.     

Effects of age, sex and breed on antipyrine disposition in calves

In domestic animals relatively little is known about the functions of hepatic microsomal enzymes and their role in biotransformation. In this study, antipyrine was used to assess microsomal oxidative function and particularly to determine the effect of age, sex and breed on drug metabolising enzymes. At birth, the elimination rate of antipyrine was very low as reflected by a half-life of 24 hours. The first two months of life were characterised by a steady decrease of antipyrine half-life values of three to four hours being reached at six months. The decrease observed during early life was not identical in the two breeds used in this experiment. By six months the Friesian calves eliminated antipyrine twice as fast as the Blue White Belgian (BWB) breed: 2.1 +/- 0.3 hours and 4.9 +/- 0.3 hours, respectively. The BWB breed is characterised by muscular hypertrophy and by a relative imbalance in muscle:body ratio. The apparent volume of distribution of antipyrine did not vary with age, sex and breed. No differences in antipyrine clearance were found between male and female calves.     

Effects of a long-acting, trace mineral, reticulorumen bolus on range cow productivity and trace mineral profiles

The objectives were to determine if strategic supplementation of range cows with a long-acting (6 mo), trace mineral, reticulorumen bolus containing Cu, Se, and Co would: (1) increase cow BCS and BW, and calf birth, weaning, and postweaning weights, or weight per day of age (WDA); (2) increase liver concentrations of Cu or Zn in cows, or blood Se, Cu, or Zn concentrations in cows and calves; and (3) vary by cow breed for any of these response variables. There were 192 control and 144 bolused Composite cows (C; 25% Hereford, Angus, Gelbevieh, and Senepol or Barzona); 236 control and 158 bolused Hereford (H) cows; and 208 control and 149 bolused Brahman cross (B) cows used in a 3-yr experiment. Cows were weighed and scored for body condition in January, May, and September, and all bolused cows received boluses in January. Each year, from among the 3 breed groups a subset of 15 control and 15 bolused cows (n = 90) had samples obtained in January and May for liver Cu and Zn, blood Se, and serum Cu and Zn. As for cows, blood and serum from the calves of these cows were sampled each year in May and September for Cu, Se, and Zn. There was a significant breed x year x treatment interaction (P = 0.001) for cow weight loss from January to May. Calf WDA, weaning, and postweaning weights did not differ (P > 0.40) between bolused and control cows, but there was a significant (P = 0.022) breed x year x treatment interaction for birth weight. Liver Cu was deficient (< 75 ppm; P < 0.001) in control cows and adequate (< 75 to 90 ppm) for bolused cows. Liver Cu differed by year (P < 0.001). Blood Se was adequate (< 0.1 ppm) for all cows except in January 2001 and 2002. There was no difference (P > 0.50) in blood Se between treatment groups in January, but bolused cows had greater (P < 0.01) blood Se in May. Breed differences for blood Se concentrations existed for bolused cows, with B having greater (P < 0.05) blood Se than either C or H cows. Breed differences also existed for control cows, with H having less blood Se (P < 0.04) than B or C cows. Calves from bolused cows had greater blood Se than calves from control cows (P = 0.01). Supplementation via a long-acting trace mineral bolus was successful in increasing liver Cu in cows and blood Se in cows and calves, but the responses varied by year. Bolus administration had variable effects on BW change in early lactation, depending on breed and year, which may indicate the need for breed- and year-specific supplementation programs.     

Birth and weaning traits in crossbred cattle from Hereford, Angus, Norwegian Red, Swedish Red and White, Wagyu, and Friesian sires

The objective of this study was to characterize breeds representing diverse biological types for birth and weaning traits in crossbred cattle (Bos taurus). Gestation length, calving difficulty, percentage of unassisted calving, percentage of perinatal survival, percentage of survival from birth to weaning, birth weight, weaning weight, BW at 205 d, and ADG was measured in 1,370 calves born and 1,285 calves weaned. Calves were obtained by mating Hereford, Angus, and MARC III (1/4 Hereford, 1/4 Angus, 1/4 Pinzgauer, and 1/4 Red Poll) mature cows to Hereford or Angus (British breeds), Norwegian Red, Swedish Red and White, Wagyu, and Friesian sires. Calves were born during the spring of 1997 and 1998. Sire breed was significant for gestation length, birth weight, BW at 205 d, and ADG (P < 0.001). Offspring from Swedish Red and White and Friesian had the shortest gestation length (282 d), whereas offspring from Wagyu sires had the longest gestation length (286 d). Progeny from British breeds were the heaviest at birth (40.5 kg) and at 205 d (237 kg), and grew faster (0.97 kg/d) than offspring from other breeds. Offspring from Wagyu sires were the lightest at birth (36.3 kg) and at 205 d (214 kg), and had the slowest growth (0.91 kg/d). Dam breed was significant for gestation length (P < 0.001), birth weight (P = 0.009), BW at 205 d, and ADG (P < 0.001). Offspring from Hereford cows had the longest gestation length (284 d), whereas offspring from Angus cows had the shortest (282 d). Offspring from MARC III cows were the heaviest at birth (39.4 kg) when compared with offspring from Hereford (38.2 kg) and Angus (38.6 kg) cows. Progeny from Angus cows were the heaviest at 205 d (235 kg) and grew faster (0.96 kg/d), whereas offspring from Hereford cows were the lightest at 205 d (219 kg) and were the slowest in growth (0.88 kg/d). Sex was significant for gestation length (P = 0.026), birth weight, BW at 205 d, and ADG (P < 0.001). Male calves had a longer gestation length (284 d) when compared with female calves (283 d). Males were heavier than females at birth and at 205 d, and grew faster. Sire breed effects can be optimized by selection and use of appropriate crossbreeding systems.     

Sire breed effects in matings with Angus cows: I. Fertility, calf survival and performance to 18 months

Over six calf crops, 524 exposures of Angus cows to three sire breeds resulted in 432 weaned calves for an 82.4% calf crop. Least-squares means for weaning rate by sire breed were 81.8, 80.5 and 83.9% for Angus, Charolais and Holsteins, respectively. Sire breed effect was not significant for calving rate, calf mortality or overall weaning rate, but was significant for all growth traits from birth to 18 mo. Angus-sired calves were smallest at birth, grew at a slower rate and were lightest in weight at all ages. Charolais-sired calves were heaviest at all weigh periods and Holstein-sired calves were intermediate. Holstein-sired calves scored significantly lower for both grade and condition than did Angus- and Charolais-sired calves. Charolais-sired calves had the highest grade. Calving rate tended to be influenced by the effect of cow (P less than .10) and sire breed X year (P less than .001). Calving rate was highest for 3-yr-old and for 6- to 10-yr-old cows and was also 1.5 percentage units higher for crossbred matings. Cow productivity (kg of calf weaned/cow exposed) is a combined measure of fertility, calf survival and weaning weight. Although sire breed did not significantly affect cow productivity (P less than .20), actual values favored cows producing crossbred calves by 14 and 9 kg for Charolais and Holstein crosses, respectively. Likewise, weight differences at 18 mo favored these crosses by 50 and 32 kg for heifers and 72 and 62 kg for steers. Among the two crossbred types, Charolais X Angus heifers were 28 kg heavier (P less than .05) than Holstein X Angus heifers at 18 mo but the 10 kg difference in steers was not significant. The fact that the large sire breeds produced calves with heavier weaning weights without demonstrating significant increases in overall productivity points out the importance of high weaning rates.     

Causes of stillbirth and time of death in Swedish Holstein calves examined post mortem

This study was initiated due to the observation of increasing and rather high levels of stillbirths, especially in first-calving Swedish Holstein cows (10.3%, 2002). Seventy-six Swedish Holstein calves born to heifers at 41 different farms were post mortem examined in order to investigate possible reasons for stillbirth and at what time in relation to full-term gestation they had occurred. The definition of a stillborn calf was dead at birth or within 24 h after birth after at least 260 days of gestation. Eight calves were considered as having died already in uterus. Slightly less than half of the examined calves (46.1%) were classified as having died due to a difficult calving. Four calves (5.3%) had different kinds of malformations (heart defects, enlarged thymus, urine bladder defect). Approximately one third of the calves (31.6%) were clinically normal at full-term with no signs of malformation and born with no indication of difficulties at parturition or any other reason that could explain the stillbirth. The numbers of male and female calves were rather equally distributed within the groups. A wide variation in post mortem weights was seen in all groups, although a number of the calves in the group of clinically normal calves with unexplained reason of death were rather small and compared with e.g. those calves categorised as having died due to a difficult calving, their average birth weight was 6 kg lower (39.9 +/- 1.7 kg vs. 45.9 +/- 1.5 kg, p < or = 0.01). It was concluded that the cause of stillbirth with a non-infectious aetiology is likely to be multifactorial and difficult calving may explain only about half of the stillbirths. As much as one third of the calves seemed clinically normal with no obvious reason for death. This is a target group of calves that warrants a more thorough investigation in further studies.     

Life-cycle evaluation of Bos taurus and Bos indicus X Bos taurus breed types in a dry, temperate climate: performance of mature dams

Mature dams representing Hereford, Red Poll, F1 Hereford x Red Poll, F1 Red Poll x Hereford, F1 Angus x Hereford, F1 Angus x Charolais, F1 Brahman x Hereford and F1 Brahman x Angus breed types were evaluated. All cows were bred to Limousin sires to produce two-way or three-way-cross progeny. Mature Brahman x Hereford dams produced a higher (P less than .05) percentage of live calves than Herefords, but dam breed differences in percentage of calves weaned relative to the number of cows exposed for mating were not statistically significant. Progeny of Angus x Charolais and Red Poll dams were outstanding in weaning weight, but Hereford and Brahman-cross calves were below average. Planned comparisons showed that Angus x Charolais calves were heavier (P less than .01) at weaning than Hereford (23.0 +/- 3.8 kg) or Angus x Hereford (9.6 +/- 3.2 kg) progeny. Mature Angus x Hereford mothers weaned heavier calves than did Brahman x Herefords (7.4 +/- 3.2 kg, P less than .05) or Brahman x Angus (10.9 +/- 3.0 kg, P less than .01). Analysis of the Hereford-Red Poll diallel showed evidence of maternal heterosis in calf weaning weight (4.0 +/- 2.6 kg, P less than .05), but there was no difference in the percentage of calves weaned by crossbred vs straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)     

Breed effects on crossbred cow-calf performance

Effects of seven breeds of cow's sire and 12 breeds of cow's maternal grandsire on preweaning performance of crossbred cows and their calves were examined in data from two experiments conducted at the Roman L. Hruska U.S. Mean Animal Research Center. Data included 1,836 records over three to five parities for 516 cows by 143 sires and by 307 maternal grandsires. The statistical model fitted effects of calf sex, parity, cow birth-breeding year or cow-calf birth year, the breed effects and their interactions. Deviations of breed of sire or equivalent grandsire effects on each trait from the mean for Hereford x Angus cows ranged from -1.6 to 5.5 kg (P less than .001) for calf birth weights, -15 to 1% (P less than .001) for calving difficulty, nonsignificant for preweaning calf mortality and -2 to 27 kg (P less than .001) for calf weaning weight. Deviations were nonsignificant for conception rate and calves weaned per cow exposed to breeding, but -2 to 40 kg (P less than .001) for calf weight weaned per cow exposed for breeding, -7 to 78 kg (P less than .001) for cow weight and -20 to 2% (P less than .001) for body condition score. The advantages of Holstein and Brahman cross over Hereford x Angus cows of 23 and 13% in weight of calf weaned/cow-breeding exposure must be compared with the expected greater feed requirements from 7 or 8% heavier cows and at least 50% higher milk production, which emphasizes the need to include input measures and costs in breed evaluation schemes.     

Genetic x environment interactions on blood constituents of Angus, Brahman, and reciprocal-cross cows and calves grazing common bermudagrass or endophyte-infected tall fescue

Over a 2-yr period, effects of genotype and forage on blood metabolites, enzymes, and minerals were determined in Angus, Brahman, Angus x Brahman (sire x dam), and Brahman x Angus cows, and 129 calves from these cows sired by Hereford bulls. Cows and calves continuously grazed either common bermudagrass or endophyte-infected 'Kentucky-31' tall fescue pastures throughout the year. Blood samples were collected via jugular venipuncture in April, August, October (weaning), and November (after 30 d in a feedlot) of each year. Plasma urea N concentrations of cows and calves were affected by forage (P < 0.01) and breed (P < 0.05). Plasma cholesterol and FFA concentrations of cows were affected by forage (P < 0.01) and breed (P < 0.05). In calves, antibody titers to infectious bovine rhinotracheitis virus were not affected by forage but were affected by breed. Serum inorganic P concentrations of calves and cows were affected by forage (P < 0.05). Serum P concentrations and alkaline phosphatase activity of calves were affected by breed (P < 0.05). Calves grazing bermudagrass had higher (P < 0.05) serum concentrations of Fe and total iron binding capacity (TIBC). There was evidence of maternal heterosis for concentrations of free fatty acids, cholesterol, aspartate aminotransferase, Ca, Mg, alkaline phosphatase, ceruloplasmin, Fe, and TIBC. There was evidence of grandmaternal effects for plasma concentrations of urea N, cholesterol, Ca, P, Mg, and alkaline phosphatase. These results suggest that calves and cows grazing tall fescue are generally on a lower plane of nutrition than those grazing bermudagrass and that Brahman x Angus and Angus x Brahman crossbred cows and their calves seen to be more tolerant of the negative effects of tall fescue than the average of their purebred contemporaries.     

Crossbreeding among British and continental European dual-purpose breeds in the coastal Pacific Northwest

From 1979 through 1987, British breed and crossbred cows were mated to Simmental, Pinzgauer or Tarentaise bulls or to Hereford-Angus crossbred bulls. Beginning in 1982, continental European crossbred females also entered the herd, to be mated for first calving to Hereford-Angus or Angus bulls and as cows to continental European or Hereford-Angus bulls. In progeny of British breed and crossbred cows, dam breed effects on birth and weaning weight were not important, but continental European crossbred calves were heavier than British crossbred contemporaries at birth and weaning. Pinzgauer- and Simmental-sired calves were heavier at birth than Tarentaise crosses, but calves sired by each of the continental breeds had similar weaning weights. Maternal heterosis was greater than direct heterosis effects on weaning weight (8% vs 5%), but only direct heterosis (13%) influenced birth weight. Within progeny of continental European crossbred cows, calves with a Tarentaise maternal grandsire were lighter at birth, with no significant difference among other maternal grandsire breeds. Maternal breed effects on weaning weight were not significant. Nevertheless, in contemporary years, continental European crossbred cows reared calves that were 10% heavier than calves reared by British crossbred cows. Pacific Northwestern cattle producers could achieve substantial increases in weaning weight from introducing inheritance from continental European dual-purpose breeds into cow herds and calf crops of British ancestry.     

Production characters of straightbred, F1 and F2 cows: birth and weaning characters of terminal-cross calves

Records of 2,449 births and 2,120 weanings of terminal-cross calves were used to characterize maternal productivity of first- and second-generation cows from a diallel of Angus, Brahman, Hereford, Holstein and Jersey when mated to third-breed sires. Third- and later-parity cows were randomly assigned after each parturition to Charolais and Red Poll bulls in multiple-sire pastures. Calves were weaned at approximately 7 mo of age; males were not castrated. A mixed model was assumed for data analysis. Effects included in the model were breed-type of dam, cow within breed-type of dam (random), breed of sire of calf, season of record, year of record, age of dam group, sex of calf and age of calf (covariate). Age of dam groups were 4- and 5-yr-olds, 6- and 7-yr-olds, 8-, 9- and 10-yr-olds, and those greater than 10 yr of age. Dependent variables were calf weight, shoulder width and hip width at birth, weaning weight, weaning height and survival to weaning. Holstein and Holstein crosses tended to produce the largest calves at birth and weaning. Among straightbred dams, the smallest calves were born to Brahman, whereas Hereford weaned the smallest calves. Brahman-Jersey dams produced the smallest calves at birth among crossbreds; Angus-Hereford cows weaned the smallest calves. Average maternal heterosis estimates for birth weight were small and non-significant. Calves of F1 crossbred dams were 17.4 kg heavier (P less than .01) and 1.70 cm taller (P less than .01) at weaning than calves of first-generation straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)     

Birth and weaning traits in crossbred cattle from Hereford, Angus, Brahman, Boran, Tuli, and Belgian Blue sires

The objective of this study was to characterize breeds representing diverse biological types for birth and weaning traits in crossbred cattle. Gestation length, calving difficulty, percentage of unassisted calving, percentage of perinatal survival, percentage of survival from birth to weaning, birth weight, BW at 200 d, and ADG were measured in 2,500 calves born and 2,395 calves weaned. Calves were obtained by mating Hereford, Angus, and MARC III (one-fourth Hereford, one-fourth Angus, one-fourth Pinzgauer, and one-fourth Red Poll) mature cows to Hereford or Angus (British breed), Brahman, Tuli, Boran, and Belgian Blue sires. Calves were born during the spring seasons of 1992, 1993, and 1994. Sire breed was significant for all traits (P < 0.002). Offspring from British breeds and the Belgian Blue breed had the shortest gestation length (285 d) when compared with progeny from other sire breeds (average of 291 d). Calving difficulty was greater in offspring from Brahman sires (1.24), whereas the offspring of Tuli sires had the least amount of calving difficulty (1.00). Offspring from all sire breeds had similar perinatal survival and survival from birth to weaning (average of 97.2 and 96.2%, respectively), with the exception of offspring from Brahman sires, which had less (92.8 and 90.4%, respectively). Progeny of Brahman sires were heaviest at birth (45.7 kg), followed by offspring from British breed, Boran, and Belgian Blue sires (average of 42.4 kg). The lightest offspring at birth were from Tuli sires (38.6 kg). Progeny derived from Brahman sires were the heaviest at 200 d (246 kg), and they grew faster (1.00 kg/d) than offspring from any other group. The progeny of British breeds and the Belgian Blue breed had an intermediate BW at 200 d (238 kg) and an intermediate ADG (average of 0.98 kg/d). The progeny of Boran and Tuli sires were the lightest at 200 d (227 kg) and had the least ADG (0.93 kg/d). Male calves had a longer gestation length, had a greater incidence of calving difficulty, had greater mortality to weaning, were heavier, and grew faster than female calves. Sire breed effects can be optimized by selection and use of appropriate crossbreeding systems.     

Cow and calf performance on Coastal or Tifton 85 Bermudagrass pastures with aeschynomene creep-grazing paddocks

Cow and calf performance was determined in a 2-yr, 2 x 2 factorial, grazing experiment using Coastal or Tifton 85 (T85) replicated Bermudagrass pastures (4 pastures each; each pasture 4.86 ha), without or with aeschynomene creep-grazing paddocks (n = 4, 0.202 ha each, planted in May of each year, 13.44 kg/ha). On June 10, 2004, and June 8, 2005, 96 winter-calving beef "tester" cows and their calves were grouped by cow breed (9 Angus and 3 Polled Hereford/group), initial cow BW (592.9 +/- 70.1 kg, 2-yr mean), age of dam, calf breed (Angus, Polled Hereford, or Angus x Polled Hereford), calf sex, initial calf age (117 +/- 20.1 d, 2-yr mean), and initial calf BW (161.3 +/- 30.4 kg) and were randomly assigned to pastures. Additional cow-calf pairs and open cows were added as the forage increased during the season. Forage mass was similar for all treatment pastures (P > 0.70; 2-yr mean, 6,939 vs. 6,628 kg/ha, Coastal vs. T85; 6,664 vs. 6,896 kg/ha, no creep grazing vs. creep grazing). Main effect interactions did not occur for performance variables (P > 0.10; 2-yr means), and year affected only the initial and final BW of the calves and cows. The 91-d tester calf ADG was greater for calves grazing T85 than Coastal (0.94 vs. 0.79 kg; P < 0.01), and for calves creep grazing aeschynomene compared with calves without creep grazing (0.90 vs. 0.82 kg; P < 0.03). Calf 205-d adjusted weaning weights were increased for calves grazing T85 compared with Coastal (252.9 vs. 240.3 kg; P < 0.01) and for calves with access to creep grazing (249.9 vs. 243.3 kg; P < 0.05). The IVDMD of esophageal masticate from pastures had a forage x creep grazing interaction (P < 0.05; Coastal, no creep grazing = 57.4%; Coastal, creep grazing = 52.1%; T85, no creep grazing = 59.1%; T85, creep grazing = 60.0%), and IVDMD was greater (P < 0.05) for T85 than for Coastal pastures. Cows were milked in August 2004, and in June and August 2005, with variable milk yields on treatments, but increased milk protein (P < 0.05) for cows grazing T85 compared with Coastal pastures in August each year, contributing to increased calf gains on T85 pastures. These results complement previous research with T85 and indicate increased forage quality and performance of cattle grazing T85 pastures. Calf gains on T85 pastures and for calves on creep-grazed aeschynomene paddocks were high enough to influence the efficiency of cow-calf operations.     

Reproductive performance in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle

Angus (A), Santa Gertrudis (S), and Gelbvieh (G) sires were mated to A and S dams to produce five mating types (A X A, S X S, S X A, A X S and G X A) in each of four calf crops. The study involved 501 matings. Overall means for the traits measured (calves born/cows exposed, Julian birthdate, calving ease, percentage of live calves at 24 h, birth weight, survival to weaning and gestation length) were 74.2%, 48.8 d, 96.4%, 33.2 kg, 95.4% and 283.8 d, respectively. Angus dams had a 14 percentage point (P less than .05) advantage over S dams for percentage of calves born/cows exposed. The effect of heterosis in crosses of A and S for percentage of calves born/cows exposed was negative (-11.1%) and approached significance. The percentage of calves born/cows exposed were 84.4, 70.4, 76.1 and 62.3 for the A X A, S X S, S X A and A X S mating types, respectively. Matings involving A sires and dams produced calves significantly earlier in the calving season than did matings involving S sires and dams. Matings involving S sires and dams produced calves with significantly longer gestation periods than matings of A sires and dams. Calving ease score and survival to weaning were not affected by breed of sire, breed of dam, age of dam, sex of calf, or the interaction of breed of sire X breed of dam. Percentage of live calves at 24 h indicated that straightbred S calves were significantly less viable at birth than the other four mating types.(ABSTRACT TRUNCATED AT 250 WORDS)     

Metabolic profile of newborn calves and levels of immunoglobulins in the first days of life

After examination of the clinical state of 128 new-born calves, blood was collected from their vena jugularis for the determination of blood actual pH value, concentration of lactic acid, pCO2, base excess, buffer base and standard acid bicarbonate. The course and difficulty of parturition exerted a significant influence on the vitality of the calves and on the studied parameters of acid-base state. In the normally born calves, compared with those after dystocia, the following values were obtained: pH 7.20 +/- 0.03 : 7.11 +/- 0.07, pCO2 = 8.4 +/- 0.9 : 10.0 +/- 1.1 kPa, base excess -2.30 +/- 2.10 : 5.80 +/- 4.60 mmol/l, buffer base 43.0 +/- 2.4 : 39.5 +/- 6.5 mmol/l, standard acid bicarbonate 22.3 +/- 1.8 : 19.6 +/- 4.1 mmol/l and lactic acid concentration 5.6 +/- 2.0 : 10.7 +/- 5.1 mmol/l. The differences were statistically significant (P less than 0.05) and statistically highly significant (P less than 0.01). The continual study of the blood actual pH value and lactic acid concentration in the calves in the first 24 hours of life showed that with the same trend of changes in calves after dystocia the initial values were less favourable and that their normalization lasted longer. Attention is drawn to the importance of dystocia for the rise of respiratory metabolic acidosis and its effect on the vitality of newborn calves, and/or on their survival. The discussion deals with the importance of immunoglobulin levels in calves in the first days after birth for their further development. The determination of antibody content in colostral serum from the first milking in 33 and 29 cows on two farms showed great drawbacks in quality. A satisfactory level of IgG was found only in 36.36% and 58.62% of the cows, and a satisfactory level of IgM only in 12.12% and 24.13% of the studied cows. The determination of immunoglobulin content in their calves two to three days from birth (33 + 33 animals) showed normoglobulinemia only in 24.24% and 15.15% of cases. In 33 and 29 cows on two farms the colostrum serum from the first milking had an average content of immunoglobulins of class G amounting to 27.99 +/- 20.25 mg/ml and 36.95 +/- 21.62 mg/ml, and class M amounting to 3.64 +/- 1.25 and 2.04 +/- 1.42 mg/ml. Three days from birth, their calves had an IgG content of 4.25 +/- 2.57 mg/ml and 3.99 +/- 1.86 mg/ml and an IgM content of 0.30 +/- 0.20 and 6.38 +/- 0.25 mg/ml.