Performance and tissue fatty acid profiles in veal calves fed diets supplemented with conjugated linoleic acids

Three groups of six calves each were fed a milk replacer at 0.8 kg and a starter concentrate ad libitum. Calves of the control group received the basal diet supplemented with rapeseed oil at 10 g per kg of feed solids. Calves of treatment groups were fed diets supplemented with a synthetically produced oil containing 62.3% methyl esters of CLA. The CLA-oil was added to milk at expense of rapeseed oil and fed at 5 and 10 g x kg(-1) feed solids for 63 days. Calves were slaughtered at 115 days of age. There was no significant effect of CLA on growth, intake of starter, feed conversion, chemical composition of meat and its oxidative stability. Dietary supplementation with CLA at 10 g x kg(-1) significantly increased CLA content in m. longissimus dorsi (MLD) from 5.6 to 19.3 mg x 100 g(-1), in liver from 13.1 to 68.8 mg x 100 g(-1), and in perirenal fat from 0.37 to 3.17 g x 100 g(-1). Dietary CLA decreased the ratio of cis-9, trans-11 and trans-10, cis-12 isomers of CLA in tissues, concentration of monounsaturated fatty acids in the MLD and fat, as well as the concentration of fatty acids with 20 and 22 carbon atoms. It can be concluded that in veal calves unprotected CLA apparently escaped ruminal hydrogenation, but was preferentially incorporated into depot fat.     

Short- and long-term effects of conventional and artificial rearing strategies on the health and performance of growing lambs

Artificial rearing of young animals represents a challenge in modern ruminant production systems. This work aims to evaluate the short- and long-term effects of the type of rearing on the animal’s health, growth, feed utilization and carcass performance. A total of 24 pregnant ewes carrying triplets were used. Within each triplet set, lambs were randomly allocated to one experimental treatment: natural rearing on the ewe (NN); ewe colostrum for 24 h followed by artificial rearing with milk replacer (NA) and 50 g of colostrum alternative supplementation followed by artificial rearing (AA). Milk replacer, ryegrass hay and creep feed were offered ad libitum, and each experimental group was kept in independent pens until weaning at 45 days of age. After weaning all lambs were placed together on the same pasture for fattening for 4 months. Blood samples were taken at 24 h after birth, at weaning and at the end of the fattening period (23 weeks). Results showed that no failure in the passive immune transfer was detected across treatments. Although artificially reared lambs at weaning had lower plasma levels of β-hydroxy-butyrate (−62%), high-density lipoproteins (−13%) and amylase (−25%), and higher levels of low-density lipoproteins (+38%) and alkaline phosphatase (+30%), these differences disappeared during the fattening period. Only the greater levels of calcium and the lower levels of haemoglobin and white blood cells detected at weaning in artificially reared lambs (+7.2%, −2.8% and −17.8%) persisted by the end of the fattening period (+4.3%, −3.3% and −9.5%, respectively). Minor diarrheal events from weeks 2 to 5 were recorded with artificial rearing, leading to lower growth rates during the 1^st month. However, these artificially reared lambs caught up towards the end of the milk feeding period and reached similar weaning weights to NN lambs. During the fattening period NN lambs had a greater growth rate (+16%) possibly as a result of their greater early rumen development, which allowed a higher feed digestibility during the fattening period in comparison to NA lambs (+5.9%). As a result, NN lambs had heavier final BWs (+7.0%), but tended to have lower dressing percentage (−5.7%) than artificially reared lambs, thus no differences were noted in either carcass weight or in carcass conformation across treatments. In conclusion, the use of a colostrum alternative and milk replacer facilitated the successful rearing of lambs, reaching similar productive parameters; however, special care must be taken to maximize the rumen development before weaning.     

Behaviour and welfare of veal calves fed different amounts of solid feed supplemented to a milk replacer ration adjusted for similar growth

Veal calves in Europe are typically fed large quantities of milk replacer and small amounts of solid feed, a diet known to lead to the development of abnormal oral behaviours in these animals. These abnormal oral behaviours are thought to be an indication of frustration, chronic stress, and hence poor welfare. The present study investigated how different feeding strategies, differing in solid feed and milk replacer provision, affected the behaviour and welfare of veal calves across time. Four treatment groups (A–D) comprising of 12 Holstein–Friesian bull calves each (7.6 ± 0.1 weeks old and 54.7 ± 0.3 kg at arrival), penned in groups of three, were fed one of four amounts of a solid feed mixture, i.e. 50% concentrates, 25% fresh maize silage, and 25% wheat straw (on dry matter [DM] basis): A = 0, B = 9, C = 18, and D = 27 g DM/kg^0.75/d. Provision of milk replacer was adjusted to achieve similar average daily gain across treatments. Behaviour was recorded around feeding (10 min continuous focal observations of individual calves) and throughout the day (7 sessions of 30 min scan sampling at 5 min interval every 2 h from 06:30 h) every week for four months. In an attempt to find an easy practical method to measure behavioural response to feeding strategy, two 3-min behavioural tests were carried out: (1) in months 1 and 3, calves were presented with a ball and latency to make oral contact with it was recorded; and (2) in month 1, calves were presented with an overall and time spent orally manipulating (i.e. chewing or licking) it was recorded using scan sampling every 10 s. Calves in treatment D displayed less abnormal oral behaviours around feeding, less tongue playing throughout the day, and more chewing in the first two months, compared to treatment A. Treatment B only led to lower tongue playing levels compared to A and treatment C had no benefit in terms of reducing abnormal oral behaviours. Although a solid feed dose–response was expected on the display of abnormal behaviours in veal calves, treatment C did not fit within this expectation. These findings point to a more complex relationship between solid feed and abnormal oral behaviour frequency in veal calves. The two behavioural tests distinguished the different treatments as expected, and thus showed a solid feed dose–response. Because of an increase in chewing and ruminating efficiency over time, amounts of solid feed should be increased with age to maintain high levels of chewing and ruminating. Moreover, high levels of chewing and ruminating may have to be maintained long enough at the beginning of the fattening period to lead to a reduction in abnormal oral behaviours.     

Digestibility of protein and amino acids of a fermentation single-cell protein for veal calves

In an experiment with veal calves, the digestibility of the SCP-product ‘Pruteen’ was determined twice, with animals of 8–9 and 15–16 weeks of age respectively. The ‘Pruteen’ was included in the milk replacer diet at a level of 20%. The ‘Pruteen’-product tested contained 74% crude protein and 10% crude fat.The average digestibility of the crude protein in ‘Pruteen’ (93.6%) was nearly as high as that of milk protein (94.2%).The apparent digestibility of the individual amino acids in milk protein and in ‘Pruteen’ was in good agreement with the digestibility of the crude protein, except for cystine in milk protein which gave a low value.The digestibility of the crude fat fraction of ‘Pruteen’ is also high, probably 90–100%.     

Comparative study of selected blood biochemical components in milk or milk-replacer fed calves during the second week of life

The experiment was carried out on 13 male Polish Black and White dairy calves of 75% share of the Holstein-Friesian (HF) breed during the second week of life. The animals were divided into two groups. One group (n=7) was fed mother's milk and the second (n=6) milk replacer. The dynamics of changes in concentration of selected blood biochemical components connected with nitrogen metabolism (plasma total protein, albumin, urea, endogenous creatinine) and with mineral metabolism (sodium, chloride, calcium, magnesium, zinc, copper and plasma osmotic pressure) were analyzed in both groups. The results show that the type of ingested food influences the concentration of indicators reflecting nitrogen metabolism. Changes of these parameters in calves fed milk replacer are possibly connected with advantageous catabolic changes. Stable concentrations of main extracellular fluid electrolytes and blood plasma osmotic pressure were found in both groups of calves. Constant blood plasma calcium, magnesium, zinc and copper concentrations observed during this study might also indicate the relative maturity of mechanisms maintaining water and electrolyte balance. Nevertheless, it seemsjustifiable to monitor the copper concentrations in plasma of young calves.     

The incorporation of solubilized wheat proteins in milk replacers for veal calves: effects on growth performance and muscle oxidative capacity

Replacement of skim milk proteins by solubilized wheat protein (SWP) in milk replacers for veal calves would contribute to the reduction in feeding costs. The occurrence of metabolic disorders has, however, been reported. Forty-two male calves received one of three treatments over 140 days: a control diet, a diet containing SWP without or with branched-chain amino acid supplementation. Liveweight gain, carcass yield, color and conformation did not show any significant differences. No metabolic disorders were noted. Supplementation with branched-chain amino acids reduced the marginal Val deficiency but did not modify the growth performances. With the SWP containing diets, the plasma metabolite profile was characteristic of those observed with non-clotting diets. It was statistically correlated to the changes in the orientation of the Semitendinosus muscle energy metabolism towards a more oxidative type and to indications of a lower efficiency of amino acid utilisation for protein deposition. At the present levels of inclusion, SWP proved to be an interesting alternative to the sole use of whey as the protein source in milk replacers for veal calves.     

Growth performance,carcass and noncarcass traits and meat quality of Barbarine lambs fed rosemary distillation residues

The aim of this experiment was to study the effect of total replacement of oat hay by rosemary distillation residues (RR) on growth, carcass characteristics and meat quality of Barbarine lambs. A total of 21 lambs were divided into three groups. The control group (C) was offered 600 g of oat hay; the RR87 and RR60 groups received 600 g of pellets containing 87% and 60% of RR, respectively. The CP content was 9% and 14% for RR87 and RR60, respectively. All animals were supplemented by 600 g of concentrate. After 77 days of fattening, lambs were slaughtered. The DM and CP intakes were significantly increased with RR diets. The average daily gain was higher (P<0.001), while the feed conversion rate was lower for RR60 and RR87 than C group. The dressing percentage was similar for all groups. The tissular (muscle, fat and bone) and the regional (leg, shoulder, etc.) carcass composition did not differ among groups. The bony organs and gut weights were similar among groups, while functional ones (skin, liver, kidney and testicles) were significantly heavier for both RR groups than control. The ultimate pH, water cooking loss and color variables were similar among groups and the chemical composition (protein, fat, myoglobin, collagen and iron) did not differ also among groups. These results revealed the opportunity of RR use in fattening lambs without adverse effects on carcass and meat characteristics. Moreover, 9% CP in RR pellets are enough given the same growth performance recorded as that of RR with 14% CP.     

Effect of alfalfa hay and starter feed supplementation on caecal microbiota and fermentation,growth, and health of yak calves

The caecum is the primary site where microbial fermentation and acidosis occurred. The supplementation of starter feed and alfalfa hay has the potential to influence caecal microbiota and then affect caecal fermentation. This study aims to investigate the effect of starter feed and alfalfa hay supplementation on caecal microbiota, immune homeostasis, and growth of preweaning yaks. Twenty 30-day-old male yak calves were randomly assigned to four groups, which separately fed with milk replacer (CON group), milk replacer with alfalfa hay (A group), milk replacer with starter feed (S group), and milk replacer with starter feed plus alfalfa hay (SA group) throughout the trial. Growth performance and plasma physiological and biochemical indicators were measured every 30 days. Calves were sacrificed at 120 days of age. The caecal contents were collected for measuring pH and contents of volatile fatty acids (VFAs) and lipopolysaccharide (LPS) and for characterizing caecal microbiota. The results indicated that individual or simultaneous supplementation with alfalfa hay and starter feed all significantly increased the BW, body height, body length, and chest girth of yak calves. However, supplementation with starter feed significantly increased plasma cortisol, nitric oxide, tumor necrosis factor-α, and interferon-γ concentrations and the ratio of aspartate aminotransferase to alanine aminotransferase of yak calves when compared with the control and alfalfa hay feeding groups, while the co-supplementation of starter feed and alfalfa hay could significantly decrease these inflammation-related indices when compared with the starter feeding group. Sequencing of the 16S rRNA gene showed that starter feed and alfalfa hay separately stimulated the proliferation of starch-decomposing and cellulose- or hemicellulose-decomposing bacteria. This also significantly increased the levels of acetate, propionate, butyrate, valerate, isobutyrate, and isovalerate in the caecal contents. Furthermore, compared with the S and CON groups, the significantly increased genera of Desulfobulbus, Olsenella, Pseudoflavonifractor, and Stomatobaculum in the SA and A groups were beneficial to the immune homeostasis, and the significantly decreased Blautia, Clostridium IV, Bacteroides, Eubacterium, Clostridium XVIII, and Mogibacterium in the SA and A groups were related to the reduced caecal lactate and LPS contents, the decreased inflammatory reaction, and the improved healthy hepatic condition of yak calves. In conclusion, milk replacer supplemented with alfalfa hay and starter feed is recommended during preweaning to improve yak calf health and growth because this regimen promotes the growth and maintains the immune homeostasis of yak calves.     

Performance and tissue fatty acid profiles in veal calves fed diets supplemented with conjugated linoleic acids

Three groups of six calves each were fed a milk replacer at 0.8 kg and a starter concentrate ad libitum. Calves of the control group received the basal diet supplemented with rapeseed oil at 10 g per kg of feed solids. Calves of treatment groups were fed diets supplemented with a synthetically produced oil containing 62.3% methyl esters of CLA. The CLA-oil was added to milk at expense of rapeseed oil and fed at 5 and 10 g · kg^?1 feed solids for 63 days. Calves were slaughtered at 115 days of age. There was no significant effect of CLA on growth, intake of starter, feed conversion, chemical composition of meat and its oxidative stability. Dietary supplementation with CLA at 10 g · kg^?1 significantly increased CLA content in m. longissimus dorsi (MLD) from 5.6 to 19.3 mg · 100 g^?1, in liver from 13.1 to 68.8 mg · 100 g^?1, and in perirenal fat from 0.37 to 3.17 g · 100 g^?1. Dietary CLA decreased the ratio of cis-9, trans-11 and trans-10, cis-12 isomers of CLA in tissues, concentration of monounsaturated fatty acids in the MLD and fat, as well as the concentration of fatty acids with 20 and 22 carbon atoms. It can be concluded that in veal calves unprotected CLA apparently escaped ruminal hydrogenation, but was preferentially incorporated into depot fat.     

Effects of lactoferrin feeding on growth, feed intake and health of calves

Lactoferrin (LF) exhibits a broad spectrum of anti-microbial properties and may have regulatory functions in the immune system. In the present study, 40 calves (20 males, 20 females) were used to examine the effects of supplemental bovine LF added to colostrum and milk replacer (at 0.16%) on health, weight development and feed intake during a 70-day experimental period. The calves were allocated to a treatment group (n = 20) and a control group (n = 20); the groups were balanced in terms of sex, live weight and date of birth. Body weight and feed intake were measured at regular intervals. Blood and colostrum samples were collected to determine the content of IgG. In addition, colostrum and milk replacer samples were analysed for their LF concentrations. Significantly higher IgG values were observed in the LF treated than in the control group during the entire feeding experiment from week 2 to week 6. Calves receiving LF had less days of disease with less serious cases of diarrhoea than the control group. Body weight and feed intake were not significantly different between the treatments; in male calves LF-treated animals tended towards higher weight gains. This study indicates that LF is advantageous for health and may therefore be a beneficial supplement in the diets for neonatal calves.     

Effect of feed intake on heat production and protein and fat deposition in milk-fed veal calves

Energy requirements for veal calves have not been updated recently despite the increased age at slaughter and the predominance of the Prim'Holstein breed in Europe. The objectives of this study were to determine the effects of four feeding levels (FLs) on protein and fat deposition and heat production in milk-fed calves at three stages of fattening and to determine energy requirements of calves. At each stage, 16 Prim'Holstein male calves (mean body weight (BW): 73.4, 151.6 and 237.4 kg) were fed a milk replacer at 79%, 87%, 95% or 103% of a reference FL. Measurements for one stage were conducted over 4 successive weeks in two open-circuit respiration chambers and consisted of a 6-day nitrogen and energy balance followed by a fasting day for estimating fasting heat production (FHP) of the calves. Heat production (HP) measurements were analyzed using a modeling approach to partition it between HP due to physical activity (AHP), feed intake (thermic effect of feeding (TEF)) and FHP. There was no effect of FL and stage on apparent digestibility coefficients, except for a tendency for increased digestibility coefficient of fat as animals got older. The metabolizable energy (ME)/digestible energy (DE) ratio did not depend on FL but decreased (P < 0.01) as animals got older in connection with marked increases in urinary glucose and urea excretion. The AHP and TEF components of HP were not affected by stage or FL and averaged 8.4% and 7.8% of ME intake, respectively. The FHP, expressed per kg BW0.85, increased with increasing FL, suggesting that also ME requirement for maintenance (MEm) may depend on FL. For an average intake of 625 kJ ME/kg BW0.85 per day (95% of the reference FL), FHP was 298 kJ/kg BW0.85 per day. Energy retention as protein and fat increased with increasing FL resulted in higher BW gain. But the rate of increase depended on stage of growth. The slope relating protein deposition to FL was lower in the finishing phase than in the growing phase, while the slope for lipid deposition was greater. Protein and fat contents of BW gain were not affected by FL but increased as animals got older. From these results, the energy requirements of veal calves are proposed according to a new approach, which considers that MEm (expressed per kg BW0.85) depends on ME intake (kJ/kg BW0.85) according to the following relationship: MEm = 197 + 0.25 × ME intake. The corresponding marginal efficiencies of ME utilization for protein and fat deposition are then 82% and 87%, respectively.     

Essential oils for dairy calves: effects on performance,scours, rumen fermentation and intestinal fauna

The first cause of death of dairy calves is often diarrhea which is mainly caused by pathogenic bacteria, which can result in excessive use of antibiotics. However, facing the increase concern by the industry and consumers, the use of antibiotics not only to control pathogens, but also to manipulate growth, has become a challenge. Alternative additives, such essential oils, have the potential to decrease antibiotic use, without reducing performance or increasing mortality of dairy calves. The objective of this study was to evaluate the use of a commercial blend of essential oils, incorporated into the calf starter and/or milk replacer to monitor the effect on overall calf performance, fecal scores and rumen fermentation parameters. A total of 30 Holstein calves received 6 l/day of a liquid diet, consisting of a commercial milk replacer containing 20% CP : 15% fat (EE). Calves had free choice access to water and calf starter. Weaning occurred at week 8, and calves were followed until the 10^th week of age. Calves were assigned to one of the three treatment groups in a randomized block design. Treatments: (1) control without essential oils supplementation (C); (2) essential oils blend in the milk replacer at 400 mg/kg (MR) and (3) essential oils blend in the milk replacer (200 mg/kg) and starter feed (200 mg/kg) (MRS). From the 2^nd week, calves were weighed and body measurements were taken, while concentrate intake and fecal scores were monitored daily. Blood samples were drawn weekly for determination of glucose and β-hydroxybutyrate. Fecal samples were collected weekly and analyzed for lactic acid bacteria and Enterobacteria; and ruminal fluid for determination of pH, short chain fatty acids, ammonia-N and counts of amylolytic and cellulolytic bacteria, and protozoa. Performance, fecal scores and intestines microorganisms were not affected by the essential oils supplementation. Ruminal and blood parameters were also not affected, with the exception the rumen ammonia-N concentration, with higher values when essential oils were supplemented in a combination of milk replacer and starter feed. Most of the evaluated parameters were affected by age of calves, mainly as a response to the increase in concentrate intake as animals’ aged. Essential oils are promising substitutes for antibiotics. However, the dose and routes of administration deserve further studies, allowing a better animal performance and health to be achieved.     

The effects of grain treatment, grain feed level and grass silage feed value on the performance of and meat quality from, finishing beef cattle

A completely randomised design study involving 132 continental crossbred beef steers was undertaken to evaluate the effects of method of grain treatment and feed level, and grass silage feed value on animal performance, carcass characteristics and meat quality of beef cattle. Winter wheat was harvested and the grain was stored either ensiled crimped and treated with 4.5 l/t of a proprietary acid-based additive (crimped), ensiled whole and treated with 20 kg feed-grade urea per t (urea) or stored conventionally in an open bin treated with 3 l propionic acid per t. Two grass silages, of contrasting feed value (L and H) were ensiled. For the conventional, crimped and urea treatments, grain dry matter (DM) concentrations were 802, 658 and 640 g/kg, respectively. For the L- and H-feed value silages, DM concentrations were 192 and 240 g/kg and D values were 671 and 730 g/kg DM, respectively. The silages were offered as the sole forage supplemented with either conventional, crimped or urea-treated grain-based concentrate at either 3.5 or 6.0 kg DM per steer per day. The grain supplement consisted of 850 and 150 g/kg DM of grain and citrus pulp, respectively. For the conventional, urea and crimped treatments, DM intakes were 8.85, 9.43 and 9.04 kg/day (standard error (s.e.) = 0.129); estimated carcass gains were 0.60, 0.55 and 0.61 kg/day (s.e. = 0.020), respectively. For the low- and high- feed value grass silages, estimated carcass gains were 0.56 and 0.61 kg/day (s.e. = 0.014), respectively. For the low and high grain feed levels, estimated carcass gains were 0.56 and 0.61 kg/day, respectively. Grain treatment, grain feed level or silage feed value did not alter (P > 0.05) meat quality, lean colour or fat colour. There were significant silage feed value × grain feed level interactions (P < 0.05) for final live weight (LW) and daily live-weight gain (DLWG). Increasing grain feed level increased final LW and DLWG when offered with the low-feed value silage, however, grain feed level had no effect on final LW or DLWG when offered with the high-feed value silage. It is concluded that urea treatment of grain increased silage intake and feed conversion ratio (kg DM intake per kg carcass) and tended to decrease carcass gain. Crimping provides a biologically equally effective method to store grain as conventional methods. Improving grass silage feed value had a greater impact on animal performance than increasing grain feed level by 2.4 kg DM per day.     

Effects of lactoferrin feeding on growth,feed intake and health of calves

Abstract

Lactoferrin (LF) exhibits a broad spectrum of anti-microbial properties and may have regulatory functions in the immune system. In the present study, 40 calves (20 males, 20 females) were used to examine the effects of supplemental bovine LF added to colostrum and milk replacer (at 0.16%) on health, weight development and feed intake during a 70-day experimental period. The calves were allocated to a treatment group (n = 20) and a control group (n = 20); the groups were balanced in terms of sex, live weight and date of birth. Body weight and feed intake were measured at regular intervals. Blood and colostrum samples were collected to determine the content of IgG. In addition, colostrum and milk replacer samples were analysed for their LF concentrations. Significantly higher IgG values were observed in the LF treated than in the control group during the entire feeding experiment from week 2 to week 6. Calves receiving LF had less days of disease with less serious cases of diarrhoea than the control group. Body weight and feed intake were not significantly different between the treatments; in male calves LF-treated animals tended towards higher weight gains. This study indicates that LF is advantageous for health and may therefore be a beneficial supplement in the diets for neonatal calves.     

The Surveys on the Urea and Allantoin Excretion and Other Criteria from Rats Fed “Threonine Imbalanced” or “Corrected” Diet

Weanling male rats of Wistar strain were fed ad libitum 7 or 8% casein-a-starch diet supplemented with 0.3% dl-methionine with ( + Thr) or without ( ?Thr) added 0.36% dl-threonine for 12 days. Urine was collected 3 times for 3 days each at one-day interval. The urine sample was analysed for allantoin, urea and total N.

There was no difference between the values of growth rate, liver and carcass fat content, protein efficiency ratio and % N retention of ?Thr and +Thr groups, whereas urea excretions of ?Thr groups were significantly higher (over 2 times) than those of +Thr and allantoin excretions were consistently lower in the former when dietary protein level was 8%.     

Influence of weaning regimen on intake,growth characteristics and plasma blood metabolites in male buffalo calves

Experiment was conducted to evaluate the effect of weaning age on growth performance, feed intake, feed efficiency (FE) and blood metabolites in Nili-Ravi male buffalo (Bubalus bubalis) calves. Twenty-four male buffalo calves were assigned to one of the three treatment groups: continuous milk feeding (CMF), limited milk feeding (LMF) and early weaning (EW), and weaned off milk at 12, 10 and 8 weeks of age, respectively. For the first 3 days after birth, calves in all three treatments were fed colostrum, and were then moved to individual milk feeding at 10% of BW for the next 6 weeks. Thereafter, the provision of milk to the CMF group was gradually tapered to zero through week 12, using week 6 intakes as a base. The LMF calves were fed milk at 7.5%, 5.0%, 3.5%, and 1.5% of BW during weeks 7 to 10, respectively. Lastly, calves in the EW group were fed milk at 5.0% and 2.5% of BW at weeks 7 and 8, respectively. Calf starter (CS) feed was also provided ad libitum from weeks 2 to 12 and individual intakes were recorded on a daily basis. Blood samples were taken from weeks 6 to 12, on a weekly basis; whereas, the BW, heart girth, withers height and hip width were measured at the start of experiment and later on a weekly basis. Weight gain, average daily gain, and body measurements were the same across all three groups. Milk intake was lower (P < 0.05), whereas CS intake was greater (P < 0.05) in the EW calves compared with the other treatment groups. Dry matter intake was greater (P < 0.05) in the EW and LMF calves compared with the CMF calves. The FE was greater (P < 0.05) in the CMF calves compared with the LMF and EW treatment groups. Blood glucose concentration was similar among the treatments; however, blood urea nitrogen was greater (P < 0.05) in the EW calves compared with the CMF and LMF groups. Plasma concentration of non-esterified fatty acids was higher (P < 0.05) in the EW calves compared with the CMF calves. In light of these results, it is evident that buffalo calves can be successfully weaned as early as 8 weeks of age without negatively affecting their growth performance.     

Effects of Gestational Maternal Undernutrition on Growth,Carcass Composition and Meat Quality of Rabbit Offspring

An experiment was conducted in order to evaluate the effects of gestational undernutrition of rabbit does on growth, carcass composition and meat quality of the offsprings. Thirty primiparous non lactating rabbit does were artificially inseminated and randomly divided in three treatment groups: Control (C; fed to 100% of maintenance requirements throughout gestation, n = 10), early undernourished (EU; fed to 50% of maintenance requirements during days 7–19 of gestation, n = 10) and late undernourished (LU; fed to 50% of maintenance requirements during days 20-27 of gestation, n = 10). During the 4^th week of the gestation period, LU does significantly lost weight compared to C and EU groups (P<0.05). At kindling, C does produced litters with higher proportions of stillborn kits (P<0.05) while the total litter size (alive and stillborn kits) was not different among groups (10.7, 12.8 and 12.7 kits in C, EU and LU groups, respectively). Kit birth weight tended to be lower in the LU group. During fattening, body weight and feed intake were not different among offsprings of the three experimental groups. Moreover, the maternal undernutrition did not have any impact on carcass composition of the offsprings in terms of carcass parts and internal organs weights as well as meat quality of L. lumborum muscle (pH24, colour, water holding capacity and shear values) at slaughter (70 days of age). Therefore, it can be concluded that the gestational undernutrition of the mother does not have detrimental effects on the productive and quality traits of the offsprings.     

Post-natal development of hematocrit in calves]

This study was carried out on 470 veal calves fed only with milk. Calves with haematocrit value before slaughter higher than 39.0, from 32.5 to 34.5 and lower than 25.0 has red, pink or white meat. Comparison between haematocrit of newborn and 3 months old calves showed two separate situations : decrease of haematocrit for values at birth higher than 38.9 and increase for values lower than 32.3.     

Animal board invited review: Specialising and intensifying cattle production for better efficiency and less global warming: contrasting results for milk and meat co-production at different scales

Cattle are the world’s largest consumers of plant biomass. Digestion of this biomass by ruminants generates high methane emissions that affect global warming. In the last decades, the specialisation of cattle breeds and livestock systems towards either milk or meat has increased the milk production of dairy cows and the carcass weight of slaughtered cattle. At the animal level and farm level, improved animal performance decreases feed use and greenhouse gas emissions per kg of milk or carcass weight, mainly through a dilution of maintenance requirements per unit of product. However, increasing milk production per dairy cow reduces meat production from the dairy sector, as there are fewer dairy cows. More beef cows are then required if one wants to maintain the same meat production level at country scale. Meat produced from the dairy herd has a better feed efficiency (less feed required per kg of carcass weight) and emits less methane than the meat produced by the cow-calf systems, because the intake of lactating cows is largely for milk production and marginally for meat, whereas the intake of beef cows is entirely for meat. Consequently, the benefits of breed specialisation assessed at the animal level and farm level may not hold when milk and meat productions are considered together. Any change in the milk-to-meat production ratio at the country level affects the numbers of beef cows required to produce meat. At the world scale, a broad diversity in feed efficiencies of cattle products is observed. Where both productions of milk per dairy cow and meat per head of cattle are low, the relationship between milk and meat efficiencies is positive. Improved management practices (feed, reproduction, health) increase the feed efficiency of both products. Where milk and meat productivities are high, a trade-off between feed efficiencies of milk and meat can be observed in relation to the share of meat produced in either the dairy sector or the beef sector. As a result, in developing countries, increasing productivities of both dairy and beef cattle herds will increase milk and meat efficiencies, reduce land use and decrease methane emissions. In other regions of the world, increasing meat production from young animals produced by dairy cows is probably a better option to reduce feed use for an unchanged milk-to-meat production ratio.