Effect of milk feed source,frequency of feeding and age at turnout on calf performance,live-weight at mating and 1st lactation milk production

Female calves (n = 108) were assigned to 6 cold milk feeding treatments in two experiments for a 70-day period. Live-weight (LW) was measured weekly, with an additional LW taken at day 410 and post-calving for animals in experiment 1. In Experiment 1, the effect of feeding frequency and age of turnout to pasture on calf performance and 1^st lactation milk yields were evaluated. The whole milk (WM) feeding treatments applied were (i) once daily feeding (OD), (ii) twice daily feeding (TD), (iii) OD feeding, outdoors at 38 days (ODO). In Experiment 2, the effects of feeding milk replacer (MR) as opposed to WM and age of turnout to pasture on calf performance were evaluated. The treatments applied were (i) OD feeding with WM (OD), (ii) OD feeding with milk replacer (MR) (ODMR), (iii) OD feeding with MR, outdoors at 38 days (ODMRO). Experiment 1: There were no differences (P > 0.05) in LW or average daily gain between TD and OD calves at day 80 or 410. ODO calves had lower LW at day 80 as compared to OD or TD (P < 0.001). Calf LW at day 80 was 86, 89 and 85 kg and at day 410 was 304, 309 and 316 kg for OD, TD and ODO, respectively. Milk feeding frequency or time of calf turnout had no effect on LW post calving, milk composition or 1st lactation milk yields. Experiment 2: Total LW at day 80 was higher (P < 0.05) for ODMR compared to OD or ODMRO calves. Calf LW was 87, 95, and 88 kg for OD, ODMR and ODMRO, respectively. However, LW at day 410 did not differ between treatments.This study showed that while some differences were observed in calf LW at day 80, these differences had no effect on LW at day 410 or 1^st lactation milk yield. It can be concluded that calves can be successfully reared when fed OD with WM or MR, indoors and when turned out to pasture at 38 days of age.     

Comparison of four methods of calf confinement. II. Behavior

Holstein bull calves (N = 46) were blocked by birth order and randomly assigned to be individually reared in stalls, pens or hutches (trials I and II) or as a group in a 3.6 X 7.9 m yard (trial II only). Treatments differed by the degree of restraint and social isolation imposed, with stalls the most restrictive and yard the least. Stalls and pens had wooden slatted floors; hutches and yard were on ground. Calves were placed on treatment within 24 h of birth and remained on treatment 6.5 wk. Total time standing or lying per 24 h in situ at 5 wk was not affected by treatment (P greater than .05), but hutch calves changed position between standing and lying more often than others (P less than .05), in order to remain in sun or shade. At 6.5 wk, calves (N = 24) in trial II were individually open-field tested for 20 min in the presence of alien calves. Stall and pen calves performed more actions utilized in locomotion and defense and engaged in more social behavior than hutch or yard calves (P less than .05). Only stall and pen calves stumbled and fell, but observations were insufficient to allow statistical analysis of these incidents. Treatment effects were found with respect to vocalizations: stall and pen calves emitted more "baaocks," while yard calves emitted more "moos." Results of this study and of a companion physiological study of the calves suggest that the intensification of drives induced by chronic suppression of their release may be accompanied by physiological responses associated with chronic stress.     

The labour input associated with calf care on Irish dairy farms

The objective of this study was to quantify the overall labour requirement for calf care and how it is influenced by enterprise scale and facilities, together with an evaluation of specific calf-feeding systems with respect to labour requirement and calf performance. One hundred and twenty nine spring-calving dairy herds participated in the investigation of overall labour input. Herds were categorized into three groups depending on herd size (small = < 50 cows, medium = 50 to 80 cows, large = > 80 cows). The total average time consumed by calf care per farm increased (P < 0.01) with herd size and the average time consumed per calf was highest in the small herd group (2.1 min/day). The proportion of farms bucket feeding was lower (P < 0.05) and the proportion feeding calves ad libitum and using cold milk was higher (P < 0.05) with the large group compared to the small herd group. Fifty-seven of the 129 herds participated in the measurement of labour input associated with specific calf-feeding systems. The labour input time per calf required for the task of milk feeding tended (P = 0.08) to be longer when calves were fed twice daily, using buckets or teats compared to automatic feeders, once daily feeding with teats and twice daily feeding with a trough. The labour input per calf for the cleaning of milk feeding equipment and for bedding and cleaning calf pens was greater (P < 0.05) with automatic feeding systems compared to the other feeding systems. A further sub-set of ten herds (from the 57 herds) underwent calf performance measurements. The mean calf weight at day 77 for automatic feeding, once daily feeding, twice daily feeding with teats and twice daily feeding with troughs was 95, 95, 93, 91 kg, respectively. In conclusion, labour input associated with calf care was influenced by herd size (and indirectly calf number), and calf-feeding system. Milk feeding of calves on a once daily basis tended to reduce the total labour input per calf and did not adversely affect calf performance. Thus, it is possible to improve efficiency of calf care by selecting time efficient methods of calf-feeding without affecting calf performance.     

Results of an online questionnaire to survey calf management practices on dairy cattle breeding farms in Austria and to estimate differences in disease incidences depending on farm structure and management practices

Background

Calf disease may result in great economic losses. To implement prevention strategies it is important to gain information on management and to point out risk factors. The objective of this internet based survey was to describe calf management practices on registered dairy breeding farms in Austria and to estimate differences in calf disease incidences depending on farm structure and management practices.

Results

A total of 1287 questionnaires were finally analysed (response rate 12.2 %). Herd characteristics and regional distribution of farms indicated that this survey gives a good overview on calf management practices on registered dairy farms in Austria. The median number of cows per farm was 20 (interquartile range 13–30). Significant differences regarding farm characteristics and calf management between small and large farms (≤20 vs >20 cows) were present. Only 2.8 % of farmers tested first colostrum quality by use of a hydrometer. Storing frozen colostrum was more prevalent on large farms (80.8 vs 64.2 %). On 85.1 % of the farms, whole milk, including waste milk, was fed to the calves. Milk replacer and waste milk were more often used on large farms. In accordance with similar studies from other countries, calf diarrhoea was indicated as the most prevalent disease. Multivariable logistic regression analysis revealed that herd size was associated with calf diarrhoea and calf respiratory tract disease, with higher risk of disease on large farms. Furthermore, feeding waste milk to the calves was associated with increasing calf diarrhoea incidence on farm. In the final model with calf respiratory tract disease as outcome, respondents from organic farms reported less often a respiratory tract disease incidence of over 10 % compared with conventional farms [odds ratio (OR) 0.40, 95 % confidence interval (CI) 0.21–0.75] and farmers that housed calves individually or in groups after birth significantly reported more often to have an incidence of respiratory tract disease >10 % compared with farms where all calves were housed individually (OR 2.28, 95 % CI 1.16–4.48).

Conclusion

The results obtained in this study provide an overview on calf management on dairy breeding farms in Austria and may help to further point out areas to be improved on farm.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-015-0134-y) contains supplementary material, which is available to authorized users.     

Comparison of four methods of calf confinement. I. Physiology

Holstein bull calves were blocked by birth order and randomly assigned to one of three treatments in trial I: stall (N = 7), pen (N = 7) and hutch (N = 7), and to one of four treatments in trial II: stall (N = 6), pen (N = 5), hutch (N = 6) and yard (N = 8). Stalls were elevated, .56 X 1.2 m, with wooden slatted floors. Stalled calves were tethered from the front with a collar and .5-m chain. Pens were elevated, 1.2 X 1.5 m, with wooden slatted floors and were located in the same open-front building as the stalls. Hutches were 1.2 X 1.2 X 2.4 m long and open on one end. Hutch calves were restrained with a dog collar and 2.4-m chain. Yard calves were housed as a group in a 3.6 X 7.9 m, outdoor enclosure, of which one-half was a covered, three-sided structure. Calves were placed on treatment between 12 to 24 h of age, bottle-fed 1.9 liters colostrum twice daily for 2 d and then bucket-fed 1.9 liters milk replacer twice daily, with continuous access to hay and grain. Jugular blood samples taken at 6 wk were analyzed for blood cell counts, blood chemistry profile (13 items), triiodothyronine (T3), thyroxine (T4), basal cortisol and adrenal response (cortisol) to exogenous adrenocorticotrophic hormone (ACTH). Average daily gain from 0 to 42 d was highly variable and was not significantly different for different treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

The impact of Theileria parva infections and other factors on calf mean daily weight gains in smallholder dairy farms in Murang’a District, Kenya

The association between mean daily weight gain, Theileria parva infections, clinical East Coast fever and other possible determinants of weight gain were examined in a longitudinal observational study that was conducted in cohorts of female calves from five agro-ecological zone (AEZ)-grazing strata. The strata were upper-midlands (UM) 1 zero-grazing, UM 1 open-grazing, UM 2 zero-grazing, UM 4 zero-grazing and UM 4 open-grazing. In total, 225 calves on 188 smallholder dairy farms were visited within the first 2 weeks of life and thereafter at biweekly intervals up to the age of 6 months between March 1995 and August 1996. During each visit, the calves were weighed and other calf-management practices in the farm during the visit such as housing, feeding and tick control also were recorded. Other events such as morbidity and mortality between or during the visits were also recorded.The overall mean daily weight gains were 0.24–0.29 kg (S.D.=0.17–0.22 kg) and were lower than the recommended targets for smallholder farms of 0.40–0.50 kg. The major tendency in variability of daily weight gains was due to visit-to-visit variation (especially in calves >3 months old).Differences in mean daily gains were associated with AEZ-grazing strata and calf-level factors that included breed of calf, calf sickness, incidence of ECF, feeding of milk, concentrate feeds and minerals and interaction between calf age and AEZ-grazing strata (P<0.05). ECF and other calf sicknesses exerted a temporal effect on calf-growth at the height of illness and immediately after; calves later recovered the lost growth except where other factors such as poor calf nutrition prevailed. Improvement in calf-growth in Murang’a District is achievable and extension services should continue to target individual-calf-level management practices.     

Rapeseed Products from Double-Low Cultivars as Feed for Dairy Cows: Effects of Long-Term Feeding on Thyroid Function,Fertility and Animal Health

Eighty-five dairy cows of the Swedish Red and White Breed (SRB) were included in a long-term experiment during 3 consecutive lactations. The cows were divided into 3 different dietary groups that received no rapeseed (NR), up to 1.2 kg dry matter (DM) 00-rapeseed meal plus 0.2 kg DM full-fat 00-rapeseed (MR), and up to 2.5 kg DM 00-rapeseed meal plus 0.9 kg DM full-fat 00-rapeseed (HR) per day. No significant differences in culling rates or disease rates were found between the feeding groups at any time during the experiment. The interval from calving to conception among the primiparous cows was longer for the HR-group (125 days) than for the NR-group (100 days). The response to a thyrotroph releasing hormone around 90 days postpartum during the first lactation was significantly higher for the HR-group (86.7 µ/L/h) than for the NR-group (55.2 µg/L/h). This indicates that at the highest level of rapeseed feeding, glucosinolates had a very mild, suppressive influence on thyroid hormone release, apparently compensated for by an increased activity along the hypothalamic-pituitary-thyroid axis. No significant differences in fertility or thyroid function were found among the pluriparous cows. During 2nd lactation the concentration of serum urea was higher in the NR-group (7.31 mmol/L) than in the HR-group (6.83 mol/L). The effects of independent environmental factors influenced fertility and thyroid function to a much greater extent than the rapeseed feeding. It was concluded that the feeding of rapeseed products from certified double low varieties of B. napus to adult dairy cows in amounts up to 3 kg rapeseed meal per cow and day would not have any negative effects on animal health or fertility.     

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

Background

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

Results

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

Conclusions

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

Effect of the number of concentrate feeding places per pen on performance, behavior, and welfare indicators of Friesian calves during the first month after arrival at the feedlot

Seventy-two Friesian calves (BW = 102.0 +/- 1.8 kg) were bought from a commercial calf farm and distributed to a factorial arrangement of treatments in a complete block design with 3 treatments and 3 blocks of similar fasted BW to study the effect of increasing the number of feeding places per pen on performance, behavior, and welfare indicators during the 4 wk after arrival. Treatments consisted of 1 (T1), 2 (T2), or 4 (T4) concentrate feeding places/pen (8 calves/pen). Concentrate and straw were fed at 0830 in individual feeders, and animals were allowed to consume on an ad libitum basis. Dry matter intake and ADG were recorded weekly, and blood samples were taken on d 0 (before transport), 7, 14, 21, and 28. Time spent in maintenance activities, number of displacements between calves, and the angular dominance value (ADV) were registered at wk 1 and 3 after arrival. Increasing the number of feeding places per pen resulted in a quadratic response of concentrate and total DMI, ADG, and BW during the 28-d period, with T1 showing the lowest values. Straw intake and the within-pen SD of ADG tended to decrease linearly (P = 0.10) as the number of feeding places per pen increased. During the 4-wk receiving period, and particularly on d 7 after arrival, serum NEFA responded quadratically, with T1 and T2 calves showing the greatest values. With increasing number of concentrate feeders, the average time spent lying increased (P = 0.001), standing time decreased linearly (P = 0.001), and the diurnal feeding pattern changed (concentrate eating time increased but straw eating time decreased during peak feeding times, P < 0.05). The number of displacements from the concentrate feeders responded quadratically (P < 0.001) with increasing number of feeding places per pen, with T4 calves showing the lowest levels of aggression. In T1 calves, increasing ADV resulted in a linear decrease (P = 0.03) of ADG at wk 1 with a quadratic effect at wk 3 (P < 0.01). In T2 calves, increasing ADV resulted in a linear decrease (P = 0.04) of ADG at wk 1 but a linear increase (P = 0.02) at wk 3. No effect of social rank on ADG was observed in T4 calves (P > 0.20). Increasing social pressure at the concentrate feeders beyond the threshold of 4 heifers per feeder had a negative effect on performance. Within-pen variability in performance increased linearly as a consequence of greater effects of social dominance. Physiological indicators of welfare were not consistently affected by treatments.     

Feeding untreated and pasteurized waste milk and bulk milk to calves: effects on calf performance,health status and antibiotic resistance of faecal bacteria

Non‐saleable milk (waste milk, WM) is contaminated with an undefined spectrum of potentially harmful pathogens and antimicrobial residues. The objective of this study was to determine the impact of feeding bulk milk (BM) or WM – both pasteurized or not – on calf performance, health and the antibiotic resistance of specific faecal bacteria. A total of 114 calves from a large‐scale dairy were housed outdoors in individual hutches and were randomly assigned to one of four feeding groups. The calves were fed either WM, pasteurized WM (pWM), BM or pasteurized BM (pBM) from day 3 to 56 of life. Milk samples taken from the pasteurizer and calves’ nipple buckets were investigated at regular intervals for total plate count and counts of thermoduric bacteria, coliforms and mastitis pathogens. Faecal samples were taken on days 2, 14, 28 and 56 of life from randomly selected calves of the WM, pWM and BM groups (each N = 8–9) and processed to obtain from each sample preferably two isolates of Escherichia (E.) coli and Enterococcus spp. respectively. Isolates were tested for their antimicrobial susceptibility to 25 antimicrobial agents by broth microdilution. Daily weight gain, milk and calf starter intake and health parameters did not differ significantly between the calves of the four feeding groups. The proportion of resistant E. coli isolates was significantly higher in calves fed WM and in calves fed pWM (most pronounced for cephalosporins) than in calves receiving BM. No differences in resistance were found for Enterococus spp. Thus, the concerns for selecting resistant faecal bacteria by feeding WM seem to be justified. Nonetheless, pasteurized WM of cows not treated with antimicrobials represents an acceptable feed for young calves.     

Administering an appeasing substance to beef calves at weaning to optimize productive and health responses during a 42-d preconditioning program

This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) to beef calves at weaning on their performance, physiological responses, and behavior during a 42-d preconditioning program. Eighty calves (40 heifers and 40 steers; 90% British × 10% Nellore) were weaned at 233 ± 2 d of age (day 0); ranked by sex, weaning age, and body weight (BW); and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 40) or placebo (diethylene glycol monoethyl ether; CON; n = 40). Treatments (5 mL) were topically applied to the nuchal skin area of each animal following dam separation. Within treatment, calves were allocated to one of eight drylot pens (four pens per treatment; pen being the experimental unit) and received a free-choice total mixed ration (TMR) from day 0 to 42, intake of which was assessed daily. Live behavior observations were conducted on days 1, 2, 4, 8, 16, and 32. Temperament was assessed and blood samples were collected via jugular venipuncture on days −21, 0, 3, 7, 14, 28, and 42. Hair samples were collected from the tail switch on days 0, 14, 28, and 42. Calves were vaccinated against bovine respiratory disease viruses on days −21 and 0. Average daily gain from day 0 to 42 did not differ between treatments (P = 0.57) but was greater (P = 0.05) in BAS vs. CON calves from day 0 to 28. Intake of TMR was greater (P = 0.05) during the first week for BAS vs. CON calves (treatment × week; P = 0.08). The mean proportion of calves feeding simultaneously and performance of social and play behaviors were greater (P ≤ 0.05) for BAS vs. CON calves. Escape attempts were greater (P < 0.01) for BAS vs. CON calves on day 1 (treatment × day; P = 0.03). Exit velocity was greater (P = 0.04) for CON vs. BAS calves on day 14 and tended (P = 0.10) to be greater for CON vs. BAS calves on day 7 (treatment × day; P = 0.03). Mean plasma concentrations of haptoglobin were greater (P = 0.02) in CON vs. BAS calves. Hair cortisol concentrations were greater (P = 0.05) in CON vs. BAS calves on day 14 (treatment × day; P = 0.03). Mean serum concentrations of antibodies against bovine viral diarrhea virus were greater (P = 0.02) in BAS vs. CON calves. Collectively, BAS administration to beef calves at weaning alleviated stress-induced physiological reactions, improved temperament evaluated via chute exit velocity, enhanced humoral immunity acquired from vaccination, and appeared to have accelerated adaptation to novel management scheme and environment.     

Hygiene management in newborn individually housed dairy calves focusing on housing and feeding practices

In calf rearing, the first weeks of life are critical and associated with the highest mortality due to enteric and respiratory diseases. A well-implemented hygiene management can help to protect calves’ health preventively by reducing the load of pathogenic bacteria and interrupting infection chains. The aim of this study was to identify deficiencies in hygiene management of individually housed dairy calves by surveying current practice and examining feeding and housing equipment with different hygiene indicators. On 11 farms, different locations in 2 pens or hutches for individual calf rearing prepared for restocking and 2 feeding buckets per farm, including the inner and outer surfaces of artificial teats, were visually scored for cleanliness and sampled with swabs (housing equipment: n = 167; feeding equipment: n = 120). The sanitation of floors was tested with sock samples (n = 41). A total of 328 samples were analyzed for adenosine triphosphate (ATP) and protein residues, aerobic total viable count (TVC), total coliform count (TCC), Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase-producing bacteria (ESBL), and Salmonella spp. After evaluation of these results, the farmers were informed about the findings and trained on improvement in hygiene management personally. The sampling was repeated after 1 year to detect possible changes in hygiene management. The highest bacterial loads (TVC, TCC, and E. coli) were observed in feeding equipment, especially the inner teat of milk feeding buckets. Environmental samples, primarily the sidewalls and back walls of tested pens and hutches, exhibited the lowest bacterial counts and ATP and protein residues. All samples were negative for MRSA and Salmonella spp. In 10.5% of all samples, ESBL was detected, and in 6.8%, ESBL E. coli was detected, predominately in sock samples, followed by feeding equipment samples. Training in hygiene management showed only limited effects. In conclusion, there is still great potential to improve the implementation of hygiene measures in individual calf housing. In particular, more attention should be paid to the cleaning of feeding buckets and artificial teats, as this is a simple means of interrupting the possible spread of pathogens among calves.     

Supplementing organic-complexed or inorganic Co,Cu, Mn,and Zn to beef cows during gestation: physiological and productive response of cows and their offspring until weaning

One hundred and ninety non-lactating, pregnant beef cows (three-fourth Bos taurus and one-fourth Bos indicus; 138 multiparous and 52 primiparous) were assigned to this experiment at 117 ± 2.2 d of gestation (day 0). Cows were ranked by parity, pregnancy type (artificial insemination = 102 and natural service = 88), body weight (BW), and body condition score (BCS) and assigned to receive a supplement containing: 1) sulfate sources of Cu, Co, Mn, and Zn (INR; n = 95) or 2) an organic-complexed source of Cu, Mn, Co, and Zn (AAC; Availa 4; Zinpro Corporation, Eden Prairie, MN; n = 95). The INR and AAC provided the same daily amount of Cu, Co, Mn, and Zn, based on 7 g of the AAC source. From day 0 to calving, cows were maintained in a single pasture and were segregated three times weekly into 1 of the 24 individual feeding pens to receive treatments. Cow BW and BCS were recorded on days −30, 97, upon calving, and at weaning (day 367). Milk production was estimated at 42 ± 0.5 d postpartum via weigh–suckle–weigh (WSW) method. Liver biopsies were performed in 30 cows per treatment on days −30, 97, upon calving, and the day after WSW. Calf BW was recorded at birth and weaning. Liver and longissimus muscle (LM) biopsies were performed in 30 calves per treatment upon calving and 24 h later, the day after WSW, and at weaning. No treatment effects were detected (P ≥ 0.49) for cow BCS during gestation, despite AAC cows having greater (P = 0.04) BW on day 97. Liver Co concentrations were greater (P < 0.01) for AAC compared with INR cows, and liver concentrations of Cu were greater (P = 0.02) for INR compared with AAC cows on day 97. Upon calving, INR cows had greater (P ≤ 0.01) liver Cu and Zn concentrations compared with AAC cows. No other treatment differences were noted (P ≥ 0.17) for cow and calf liver trace mineral concentrations. Cows receiving AAC had greater (P = 0.04) hepatic mRNA expression of metallothionein 1A at calving, and their calves had greater (P = 0.04) hepatic mRNA expression of superoxide dismutase at weaning. Milk production did not differ between AAC and INR cows (P = 0.70). No treatment effects were detected (P ≥ 0.29) for mRNA expression of LM genes associated with adipogenic or muscle development activities in calves at birth and weaning. Calf birth and weaning BW also did not differ (P ≥ 0.19) between treatments. In summary, supplementing AAC or INR to beef cows during the last 5 mo of gestation yielded similar cow–calf productive responses until weaning.     

Effects of two different rearing protocols for Holstein bull calves in the first 3 weeks of life on health status,metabolism and subsequent performance

The aim of this study was to investigate the impact of weight gain of calves within the first 3 weeks of life on health status and subsequent performance. Holstein bull calves were reared either intensively (IR; individual hutches and ad libitum milk feeding for the first 3 weeks of life; n = 24), or according to the established protocol [ER; 4 l milk/day in hutches during week 1 and 720 g/day milk replacer (MR) from day 8 to 21 in a group pen; n = 24]. Water, hay and concentrates were freely available to all calves. From week 4, calves of both groups were housed together in a group pen and fed 720 g MR/day; step‐down weaning was performed between week 5 and 10. Key metabolic blood parameters were analysed on day 2, 12, 21 and 70 of life. After weaning, all animals were fed concentrates and corn silage until slaughter at an age of 8 months. Within the first 3 weeks, average daily weight gain was threefold higher in IR calves in relation to ER calves (1.28 vs. 0.38 kg/day, p < 0.001). Neither incidence nor duration of scouring differed significantly between groups. Starter intake (week 4–10) was higher in IR calves in relation to ER calves (49.7 vs. 38.0 kg/calf, p = 0.006). Serum glucose, urea, albumin and insulin were higher at an age of 21 days in IR calves in relation to ER calves; no differences were obvious at an age of 70 days. Plasma GH and IGF‐I concentrations revealed an uncoupling of the somatotropic axis in ER calves within the first 3 weeks of life. At slaughter, body weight of IR calves tended to be higher than that of the ER calves (320 vs. 309 kg, p = 0.07). In conclusion, intensive feeding and individual housing during the first 3 weeks of life had positive long‐term effects on subsequent performance.     

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

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

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

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

     

Metabolism and Distribution of 131 I-labelled Albumin in the Pig

The biological behaviour of porcine ¹³¹I-albumin has been investigated in 11 normal pigs, weight appr. 20 kg. Mean values obtained from the experiments are: Albumin degradation: 15.1 ± 2.1 per cent/day (0.18 ± 0.01 g/kg/day), extravascular: intravascular albumin ratio: 1.71 ± 0.29. Fecal excretion of radio-activity ranged from 0.77—1.87 per cent of the dose (mean: 1.11 per cent) during the first 4 days of the experiment.

The results are discussed with special reference to the rôle of the gastrointestinal tract in health and in various digestive disorders.

     

Effects of dietary Forsythia suspensa extract supplementation to lactating sows and nursery pigs on post-weaning performance,antioxidant capacity,nutrient digestibility,immunoglobulins, and intestinal health

The aim of this study was to determine the effect of dietary Forsythia suspensa extract (FSE) supplementation to lactating sows and nursery pigs on post-weaning performance, antioxidant capacity, immunoglobulins, and intestinal health. Based on backfat, body weight (BW), and parity, 24 gestating sows (Landrace × Yorkshire) with average parity of 3.38 ± 0.61 and BW of 234 ± 6.81 kg were allotted into two dietary treatments (control vs. 100 mg/kg FSE) with 12 sows per treatment from day 107 of gestation to day 21 of lactation. After weaning, based on the initial BW and source litter, 192 nursery pigs (Duroc × [Landrace × Yorkshire], average BW of 6.98 ± 0.32 kg, weaned at day 21) were allotted into four dietary treatments with eight replicate pens per treatment, six pigs per pen for a 4-wk study. The treatments included the following: 1) CC (sows and their piglets both fed control diet); 2) CF (sows fed control diet and their piglets fed FSE diet [containing 100 mg/kg FSE]); 3) FC (sows fed FSE diet and their piglets fed control diet); and 4) FF (sows and their piglets both fed FSE diet). The MIXED procedures of SAS for a split-plot arrangement with sow diet as the whole plot and nursery diet as split plot were used to analyze the data. After weaning, piglets from FSE-fed sows had improved (P < 0.05) average daily gain and feed efficiency, and lower (P < 0.05) diarrhea rate in overall (day 1 to 28) compared with those from sows fed control diet. Piglets from FSE-fed sows also had higher (P < 0.05) contents of immunoglobulin G (IgG), growth hormone, superoxide dismutase (SOD), total antioxidant capacity in serum, villus height in ileum, and villus height to crypt depth ratio in jejunum, as well as lower (P < 0.05) content of malondialdehyde (MDA) in serum and crypt depth in ileum compared with those from sows fed control diet. Piglets fed FSE during nursery had increased (P < 0.05) concentrations of IgG, SOD, and catalase, and decreased (P < 0.05) MDA and tumor nuclear factor-α levels in serum compared with those fed control diet during nursery. Piglets from FC group had increased (P < 0.05) protein expression of occludin in jejunal mucosa and relative abundance of Lactobacillus on genus level in colon compared with those from CC group. In conclusion, for the performance and intestinal health, diets supplemented with FSE during lactation phase seemed more efficient to alleviate weaning stress than the nursery phase. In terms of the antioxidant status and immunoglobulins, FSE supplemented in both phases were efficient for nursery pigs.     

Associations between maternal milk protein genotypes with preweaning calf growth traits in beef cattle

The objectives of this study were to investigate milk casein polymorphisms in dams and to determine the impacts of maternal casein genotypes on growth traits of their sucking calves. Milk samples from 433 dams of the breeds German Angus (GA) and German Simmental (GS) were typed at the milk protein loci α _s1-casein (α_s1-CN), β-casein (β-CN), α _s2-casein (α_s2-CN), and κ-casein (κ-CN) via isoelectric focusing. Associations between casein genotypes in maternal milk with growth traits of their 1,872 calves were analyzed until the age of weaning using linear mixed models, considering either genotypes of individual casein loci (model 1) or composite α _s1-β-α _s2-κ-CN genotypes within the casein cluster (model 2). Besides environmental effects such as sex, age of the dam, and calving year-season, genetic effects (breed group and maternal and paternal effects) were considered in statistical models. The composite casein genotype BBǀA2A2ǀAAǀAB (order of genes on bovine chromosome 6: α _s1-ǀβ-ǀα _s2-ǀκ-CN) was associated with greater average daily weight gains (ADG) and heavier age-adjusted weaning weights (WW) of calves (P < 0.05). The effects of composite genotypes on birth weight of calves were similar (P > 0.05; model 2). With regard to individual casein loci, greater ADG and WW were observed for calves from dams with the genotypes κ-CN BB and α _s1-CN BB, respectively (P < 0.05; model 1). Age-adjusted WW was largest for calves from dams carrying the κ-CN genotype BB (215 kg) compared with calves representing the maternal AB and AA genotypes (both 204 kg). Results from the present study suggested selectable casein genotypes due to their nutritional value of milk (value in terms of offspring performances), offering new perspectives for breeding strategies in beef cattle to improve preweaning calf performance.     

III. Comparison of Two Complement-Fixation Methods

The complement-fixation test used at Onderstepoort was compared with the method used at A.D.R.I. on infected calf and sheep sera. In the first method, the tests are incubated at 37°C for 90 minutes and the test sera are inactivated at 53°C; whereas in the A.D.R.I. method, the test sera are inactivated at 60°C for 30 minutes, incubation is at 9°C for 18 hours, and guinea-pig complement is supplemented with 5 per cent fresh, non-inactivated, normal calf serum. Serial serum samples from one of six experimentally infected calves were negative in the Onderstepoort test, three calves gave only trace reactions and two showed maximum titres of 1:10 whereas all six had maximum serum titres of 1:10 to 1:80 in the A.D.R.I. test. A good correlation was obtained, however, between the results of the two methods with the sera of experimentally inoculated sheep although titres 3 to 8 times higher were obtained with the A.D.R.I.'s test. Post inoculation bleedings from each sheep reacted in both tests.     

Effects of weaning age and milk feeding frequency on dairy calf growth, health and rumen parameters

Various methods can be used to feed dairy calves that may influence calf performance and these include changing frequency of feeding or age at weaning. Two trials were conducted to determine effects of feeding frequency and weaning age on calf growth, health and rumen development, where 124 Holstein heifer and bull calves were weaned at 3, 4, 5 or 6 weeks of age. During Trial 1, milk replacer (12.5% DM; 22% CP, 15.6% fat) was fed at 10% BW twice per day until 1 week prior to weaning when intake was reduced to 5% BW. During Trial 2 calves were fed at 10% BW in two feedings until 14 days, then at 10% BW once daily until 1 week prior to weaning when milk replacer was reduced to 5% BW. Blood glucose and urea nitrogen, BW 4 h post-feeding, heart girth, hip height, and withers height 4 h post-feeding were obtained weekly. Growth and structural measurements were similar for all treatments up to 8 weeks of age in both trials. Blood constituents and health observations were not different between trials. Similar growth and performance between treatments in both trials through 8 weeks of age indicate that calf performance is not affected by weaning early and feeding once daily.