The study was conducted to investigate the effects of fish or palm oil diets with different roughage levels on dairy performance, milk physicochemical composition and apparent transfer efficiency of fatty acids (FA) in goat milk. The experiment was conducted with 40 Aleppo goats with a mean parity of 2.53 ± 0.8 (multiparous), mean initial body weight of 47.23 kg and 25 ± 5 days in milk which were allocated to four (2 × 2) experimental diets with two oil sources (fish or palm oil) at 25.6 g/kg of dietary dry matter and forage levels (400 or 600 g/kg). The experimental data were analysed by repeated measures analysis, using the MIXED procedure. The concentrations of saturated FA decreased with high forage level and fish oil diets; however, the fish oil diets caused an increase in C14 saturated FA. Fish oil diets with high roughage levels more efficiently increased conjugated linoleic acid, n-6 (18 : 2), and n-3 (20 : 5). The apparent transfer efficiency of 18 : 1, 18 : 2, 18 : 3 and 20 : 5 decreased and the transfer efficiency of 22 : 6 increased with the use of fish oil in the diet. The roughage level did not affect the apparent transfer efficiency of 18 : 1 and 18 : 2, but the low roughage level increased the apparent transfer efficiency of 20 : 5. High roughage diets improved milk quality parameters through increasing eicosapentaenoic acid, polyunsaturated fatty acids (PUFA), PUFA/saturated FA and atherogenicity index, thus it was concluded that dietary roughage level could be considered as an important designator of milk quality when a supplement of fish oil and palm oil was supplied to goats.

Current available methods to detect cow milk adulteration or accidental contamination of goat milk are both laborious and time consuming. The aim of this technical research communication was to develop a simple, rapid, specific and sensitive method for quantitative detection of cow milk in goat milk. A competitive lateral flow immunoassay (LFIA) strip was developed using a specific monoclonal antibody (mAb) labeled with colloidal gold nanoparticles (GNPs) for specifically binding to cow milk casein. The detection limit of this rapid detection was 0.07% of cow milk in goat milk, providing equal specificity and higher sensitivity when compared with a commercial enzyme-linked immunosorbent assay (ELISA). These result suggest that the established rapid GNPs-LFIA strip could be used for monitoring cow milk adulteration/contamination of goat milk.

Malnutrition remains a leading contributor to the morbidity and mortality of children under the age of 5 years and can weaken the immune system and increase the severity of concurrent infections. Livestock milk with the protective properties of human milk is a potential therapeutic to modulate intestinal microbiota and improve outcomes. The aim of this study was to develop an infection model of childhood malnutrition in the pig to investigate the clinical, intestinal and microbiota changes associated with malnutrition and enterotoxigenic Escherichia coli (ETEC) infection and to test the ability of goat milk and milk from genetically engineered goats expressing the antimicrobial human lysozyme (hLZ) milk to mitigate these effects. Pigs were weaned onto a protein–energy-restricted diet and after 3 weeks were supplemented daily with goat, hLZ or no milk for a further 2 weeks and then challenged with ETEC. The restricted diet enriched faecal microbiota in Proteobacteria as seen in stunted children. Before infection, hLZ milk supplementation improved barrier function and villous height to a greater extent than goat milk. Both goat and hLZ milk enriched for taxa (Ruminococcaceae) associated with weight gain. Post-ETEC infection, pigs supplemented with hLZ milk weighed more, had improved Z-scores, longer villi and showed more stable bacterial populations during ETEC challenge than both the goat and no milk groups. This model of childhood disease was developed to test the confounding effects of malnutrition and infection and demonstrated the potential use of hLZ goat milk to mitigate the impacts of malnutrition and infection.

Two experiments were carried out to investigate how milking in mid-line (ML) affects the lipolysis level and milk composition in goat livestock, in comparison with low-line (LL) milking. The first experiment took place, in triplicate, on an experimental farm. For each replicate, a crossover design (62 goats, two treatments, ML and LL, in two periods each lasting 4 days) was used. Milk samples were taken daily at 0 and 24 h after milking. In the first experimental replicate, some enzymatic coagulation cheeses were made, which were assessed by a panel of tasters at 50 and 100 days of maturation. In the second experiment, the lipolysis level and composition of tank milk from 55 commercial dairy goat farms (25 ML and 30 LL) were analysed, in milk samples taken in three different weeks. The results of the first experiment showed that ML milking increased free fatty acid (FFA) concentration in raw goat's milk significantly (0.71 v. 0.40 mmol/l, respectively). However, in the milk samples taken from commercial farms the FFA concentration remained unaffected by the milking pipeline height (0.59 v. 0.58 mmol/l for ML and LL, respectively). No significant differences were found in the milk composition, nor in the sensory characteristics in the cured cheeses, which suggests that factors other than the milkline height are able to influence the level of lipolysis under commercial conditions. Therefore, ML milking should not be discouraged, provided that the correct functioning and management of the milking operation and milk storage on the farm is guaranteed.

The aim was to determine the effect of substituting pumpkin seed cake (PSC) or extruded linseed (ELS) for soya bean meal in goats’ diets on milk yield, milk composition and fatty acids profile of milk fat. In total, 28 dairy goats were divided into three groups. They were fed with concentrate mixtures containing soya bean meal (Control; n=9), ELS (n=10) or PSC (n=9) as main protein sources in the trial lasting 75 days. Addition of ELS or PSC did not influence milk yield and milk gross composition in contrast to fatty acid profile compared with Control. Supplementation of ELS resulted in greater branched-chain fatty acids (BCFA) and total n-3 fatty acids compared with Control and PSC (P<0.05). Total n-3 fatty acids were accompanied by increased α-linolenic acid (ALA, C18:3n-3; 0.56 g/100 g fatty acids) and EPA (C20:5n-3; 0.12 g/100 g fatty acids) proportions in milk of the ELS group. In contrast, ELS and PSC resulted in lower linoleic acid (LA, C18:2n-6; 2.10 and 2.28 g/100 g fatty acids, respectively) proportions compared with Control (2.80 g/100 g fatty acids; P<0.05). Abovementioned resulted in lower LA/ALA ratio (3.81 v. 7.44 or 6.92, respectively; P<0.05) with supplementation of ELS compared with Control or PSC. The PSC diet decreased total n-6 fatty acids compared with the Control (2.96 v. 3.54 g/100 g fatty acids, P<0.05). Oleic acid (c9-C18:1), CLA (c9,t11-18:2) and t10-,t11-C18:1 did not differ between treatments (P⩾0.08), although stearic acid (C18:0) increased in ELS diets compared with Control (12.7 v. 10.2 g/100 g fatty acids, P<0.05). Partially substituted soya bean meal with ELS in hay-based diets may increase beneficial n-3 fatty acids and BCFA accompanied by lowering LA/ALA ratio and increased C18:0. Pumpkin seed cake completely substituted soya bean meal in the diet of dairy goats without any decrease in milk production or sharp changes in fatty acid profile that may have a commercial or a human health relevancy.

This Research Communication reports interferences related to the administration of ivermectin in lactating dairy goats on the response of microbial tests for screening antibiotics in milk. Twenty-eight Murciano-Granadina goats, naturally infested with Sarcoptes scabiei var. caprae, were treated with a subcutaneous injection of ivermectin (200 µg/kg b.w.). To prevent re-infestation, a second dose was applied 7 d later. Individual milk samples were collected, daily, up to 15 d post-treatment. Milk samples were analysed by microbial inhibitor tests (BRT MRL, Delvotest SP-NT MCS and Eclipse 100) and ivermectin residues were quantified by HPLC. A large number of positive results were obtained for all microbial tests, especially on the first day after treatment (BRT MRL = 46·4%; Delvotest SP-NT MCS = 14·3%; and Eclipse 100 = 17·8%). However, the highest concentration of drug residues in milk (24·3 ng/ml) was detected on the tenth day after treatment, when positive outcomes were relatively lower (BRT MRL = 17·8%; Delvotest SP-NT MCS = 10·7%; and Eclipse 100 = 7·4%). Results herein suggest that factors related to the ivermectin treatment other than drug residues in milk, or alterations produced by the parasitic disease itself affecting the immune response of animals, could be the cause of false-positive results in microbial tests. It can be concluded that the application of ivermectin in dairy goats infested with sarcoptes mange during lactation produces persistent drug residues in milk, and could also cause false-positive results in microbial inhibitor tests for screening antibiotics.

This study was designed to assess anti-diabetic potential of goat, camel, cow and buffalo milk in streptozotocin (STZ) induced type 1 diabetic albino wistar rats. A total of 48 rats were taken for the study where one group was kept as non-diabetic control group (8 rats) while others (40 rats) were made diabetic by STZ (50 mg/kg of body weight) injection. Among diabetic rats, a control group (8 rats) was kept and referred as diabetic control whereas other four groups (8 rats each) of diabetic rats were fed on 50 ml of goat or camel or cow or buffalo milk for 4 weeks. All the rats (non-diabetic and diabetic) were maintained on standard diet for four weeks. STZ administration resulted in enhancement of glucose, total cholesterol, triglyceride, low density lipoprotein, HbA1c and reduction in high density lipoprotein in plasma and lowering of antioxidative enzymes (catalase, glutathione peroxidase and superoxide dismutase) activities in pancreas, kidney, liver and RBCs, coupled with enhanced levels of TBARS and protein carbonyls in pancreas, kidney, liver and plasma. OGTT carried out at the end of 4 week milk feeding indicated that all milks helped in early maintenance of glucose level. All milks reduced atherogenic index. In camel milk fed diabetic group, insulin concentration enhanced to level noted for non-diabetic control while goat, cow and buffalo milk failed to restore insulin level. HbA1c level was also restored only in camel milk fed diabetic group. The level of antioxidative enzymes (catalase, GPx and SOD) in pancreas enhanced in all milk fed groups. Camel milk and to a reasonable extent goat milk reduced formation of TBARS and PCs in tissues and blood. It can be concluded that camel milk ameliorates hyperglycaemia and oxidative damage in type-1 diabetic experimental rats. Further, only camel milk completely ameliorated oxidative damage in pancreas and normalised insulin level.

The variability of the promoter region and the 3′UTR (exon-7) of the BLG gene, encoding the β-lactoglobulin, was investigated by sequencing in 263 lactating Sarda goats in order to assess its association with milk traits. Milk traits included: milk yield, fat, total protein and lactose content, pH, daily fat and protein yield (DFPY), freezing point, milk energy, somatic cell count, total microbial mesophilic count, rennet coagulation time (RCT), curd firming rate (k20) and curd firmness (a30). A total of 7 polymorphic sites were detected and the sequence analysed was given accession number KM817769. Only three SNPs (c.−381C>T, c.−323C>T and c.*420C>A) had minor allele frequency higher than 0·05. The effects of farm, stage of lactation and the interaction farm × stage of lactation significantly influenced all the milk traits (P < 0·01, P < 0·001) except for lactose content and SCS, which were not affected by the farm, and RCT and k20, which were not affected by the stage of lactation. The BLG gene polymorphism influenced milk yield and DFPY, in relation to SNPs c.−381C>T and c.*420C>A (P < 0·01 and P < 0·05). All three SNPs affected milk pH, and this association was highly significant at c.−381C>T (P < 0·001). The c.−381TT homozygous goats showed lower pH, RCT and k20 than c.−381CT (P < 0·05). In conclusion the polymorphism of the goat BLG gene did not affect the total protein content of the Sarda goat milk, and only weakly influenced RCT and k20. On the other hand, an interesting effect on milk yields and DFPY emerged in two SNPs. This information might be useful in dairy goat breeding programs.

The 5′ flanking region and 3′ UTR of the caprine LALBA gene were analysed by SSCP and sequencing. A total of nine SNPs were detected: three in the promoter region, two were synonymous coding SNPs at exon-1, and four SNPs were in exon-4, within the 3′UTR. The nucleotide changes located in the promoter region (c.−358T>C, c.−163G>A, c.−121T>G) were genotyped by SSCP in 263 Sarda goats to evaluate their possible effect on milk yield, composition and renneting properties. We observed an effect of the three SNPs on milk yield and lactose content. Genotypes TT and CT at c.−358T>C (P < 0·001) and genotypes AG and GG at c.−163G>A (P < 0·01) were characterised by higher lactose contents, while c.−358CC and c.−163AA showed the lower milk yield (P < 0·01). SNPs c.−358T>C and c.−121T>G were part of transcription factors binding sites, potentially involved in modulating the LALBA gene expression. The LALBA genotype affected renneting properties (P < 0·001), as heterozygotes c.−358CT and c.−163GA were characterised by delayed rennet coagulation time and curd firming time and the lowest value of curd firmness. The present investigation increases the panel of SNPs and adds new information about the effects of the caprine LALBA gene polymorphism.

Based on the potential benefits for long-term human health, there is interest in developing sustainable nutritional strategies for lowering medium-chain saturated fatty acids (FA) and increasing specific unsaturated FA in ruminant milk. Dietary supplements of extruded linseeds (EL), fish oil (FO) or a mixture of EL and FO increase cis-9,trans-11 CLA and long-chain n-3 polyunsaturated FA in bovine milk. Supplements of FO cause milk fat depression in lactating cows, but information for dairy goats is limited. A total of 14 Alpine goats were used in a replicated 3×3 Latin square with 28-days experimental periods to examine the effects of EL alone or in combination with FO on animal performance, milk fat synthesis and milk FA composition. Treatments comprised diets based on natural grassland hay supplemented with no additional oil (control), 530 of EL or 340 g/day of EL and 39 g/day of FO (ELFO). Compared with the control, ELFO tended (P=0.08) to lower milk fat yield, whereas EL increased (P<0.01) milk fat content and yield (15% and 10%, respectively). Relative to EL, ELFO decreased (P<0.01) milk fat content and yield (19% and 17%, respectively). Relative to the control and ELFO, EL decreased (P<0.05) milk 10:0 to 16:0 and odd- and branched-chain FA content and increased 18:0, cis-18:1, trans-13 18:1 (and their corresponding ∆-9 (desaturase products), trans-12,cis-14 CLA, cis-13,trans-15 CLA, cis-12,trans-14 CLA and trans-11,cis-13 CLA and 18:3n-3 concentrations. ELFO was more effective for enriching (P<0.05) milk cis-9, trans-11 CLA and trans-11 18:1 concentrations (up to 5.4- and 7.1-fold compared with the control) than EL (up to 1.7- and 2.5-fold increases). Furthermore, ELFO resulted in a substantial increase in milk trans-10 18:1 concentration (5.4% total FA), with considerable variation between individual animals. Relative to the control and EL, milk fat responses to ELFO were characterized by increases (P<0.05) in milk trans-16:1 (Δ9 to 11), trans-18:1 (Δ6 to 11), trans-18:2, CLA (cis-9,trans-11, trans-9,cis-11, trans-8,trans-10 and trans-7,trans-9) and 20- and 22-carbon FA concentrations. Overall, EL resulted in a relatively high cis-9 18:1 concentration and an increase in the 18:3n-3/18:2n-6 ratio, whereas combining EL and FO resulted in substantial increases in trans-FA, marginal enrichment in 20:5n-3 and 22:6n-3 and lower 16:0 concentration changes associated with a decrease in milk fat content. In conclusion, data provide further evidence of differential mammary lipogenic responses to diet in the goat compared with the cow and sheep.

The safety and nutritional adequacy of goat milk infant formulas have been questioned. The primary aim of the present study was to compare the growth and nutritional status of infants fed a goat milk infant formula with those of infants fed a typical whey-based cow milk infant formula. The secondary aim was to examine a range of health- and allergy-related outcomes. A double-blind, randomised controlled trial with 200 formula-fed term infants randomly assigned to receive either goat or cow milk formula from 2 weeks to at least 4 months of age was conducted. A cohort of 101 breast-fed infants was included for comparison. Weight, length and head circumference were measured at 2 weeks and 1, 2, 3, 4, 6 and 12 months of age. Nutritional status was assessed from serum albumin, urea, creatinine, Hb, ferritin, and folate and plasma amino acid concentrations at 4 months. Z-scores for weight, length, head circumference and weight for length were not different between the two formula-fed groups. There were differences in the values of some amino acids and blood biomarkers between the formula-fed groups, but the mean values for biomarkers were within the normal reference range. There were no differences in the occurrence of serious adverse events, general health, and incidence of dermatitis or medically diagnosed food allergy. The incidence of parentally reported blood-stained stools was higher in the goat milk formula-fed group, although this was a secondary outcome and its importance is unclear. Goat milk formula provided growth and nutritional outcomes in infants that did not differ from those provided by a standard whey-based cow milk formula.

This study assessed the effects of dietary supplementation with extruded linseed on milk yield and composition, milk fatty acid (FA) profile and renal and hepatic metabolism of grazing goats in mid-lactation. Forty Saanen goats were divided into two isoproductive groups: one group was fed the control diet (CON) composed of hay and pelleted concentrate and the other group was supplemented with additional 180 g/day of extruded linseed (LIN; dry matter basis), which supplied 70 g/day of fat per head for 9 weeks. Animals grazed on pasture for ∼3 h/day after the first of the 2 daily milkings. Milk samples were collected weekly and analyzed for fat, protein, lactose, milk urea nitrogen (MUN) and somatic cell count. Blood samples were collected every 2 weeks and analyzed for total bilirubin, creatinine, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyl transpeptidase, alkaline phosphatase, total protein and urea nitrogen. Milk yield was higher in the LIN than in the CON group (2369 v. 2052 g/day). LIN group had higher milk fat (37.7 v. 33.4 g/kg) and protein (30.7 v. 29.1 g/kg) concentration and lower MUN (35.0 v. 43.3 mg/dl) than CON group. Goats fed LIN had greater proportions of 18:1 trans11, 18:2 cis9trans11 and total polyunsatured fatty acids n-3 in milk fat, because of higher 18:3n-3 and 20:5n-3 FA, and lower proportions of short- and medium-chain FAs than goats fed CON. All kidney and liver function biomarkers in serum did not differ between dietary groups, except for AST and ALT, which tended to differ. Extruded linseed supplementation to grazing mid-lactating goats for 2 months can enhance the milk performance and nutritional profile of milk lipids, without altering the general hepatic and renal metabolism.

Despite Fe deficiency and overload having been widely studied, no studies are available about the influence of milk consumption on antioxidant defence and lipid peroxidation during the course of these highly prevalent cases. The objective of the present study was to assess the influence of cow or goat milk-based diets, either with normal or Fe-overload, on antioxidant defence and lipid peroxidation in the liver, brain and erythrocytes of control and anaemic rats after chronic Fe repletion. Weanling male rats were randomly divided into two groups: a control group receiving a normal-Fe diet (45 mg/kg) and an anaemic group receiving a low-Fe diet (5 mg/kg) for 40 d. Control and anaemic rats were fed goat or cow milk-based diets, either with normal Fe or Fe-overload (450 mg/kg), for 30 or 50 d. Fe-deficiency anaemia did not have any effect on antioxidant enzymes or lipid peroxidation in the organs studied. During chronic Fe repletion, superoxide dismutase (SOD) activity was higher in the group of animals fed the cow milk diet compared with the group consuming goat milk. The slight modification of catalase and glutathione peroxidise activities in animals fed the cow milk-based diet reveals that these enzymes are unable to neutralise and scavenge the high generation of free radicals produced. The animals fed the cow milk diet showed higher rates of lipid peroxidation compared with those receiving the goat milk diet, which directly correlated with the increase in SOD activity. It was concluded that goat milk has positive effects on antioxidant defence, even in a situation of Fe overload, limiting lipid peroxidation.

The potential benefits on human health have prompted an interest in developing nutritional strategies for reducing saturated and increasing specific unsaturated fatty acids (FA) in ruminant milk. The impact of the level and type of starchy concentrate added to diets supplemented with sunflower-seed oil on caprine milk FA composition and on mammary, omental and perirenal adipose, and liver lipid metabolism was examined in fourteen Alpine goats in a replicated 3 × 3 Latin square with 21 d experimental periods. Treatments were a grass hay-based diet with a high level of forage (F) or a high level of concentrate with either maize grain (CM) or flattened wheat (CW) as source of starch and supplemented with 130 g/d sunflower-seed oil. Milk yield was enhanced (P < 0·01) and milk fat content was decreased on the CM and CW diets compared with the F diet, resulting in similar milk fat secretion. Both high-concentrate diets increased (P < 0·05) milk yield of 10 : 0-16 : 0 and decreased trans-9,11-18 : 1 and cis-9, trans-11-18 : 2. The CW diet decreased (P < 0·05) the output of Σ C18 and Σ cis-18 : 1 and increased (P < 0·05) the output of trans-10-18 : 1 in milk. The expression and/or activity of fourteen proteins involved in the major lipogenic pathways in mammary tissues and of lipogenic genes in adipose and liver tissues were similar among treatments. In conclusion, high starch concentrates alter milk FA yield via mechanisms independent of changes in mammary, liver or adipose tissue lipogenic gene expression. Furthermore, data provided indications that mammary lipogenic responses to starch-rich diets differ between caprine and bovine ruminants.

This study evaluated the effect of storage on renneting properties of goat milk investigated using the Formagraph method. Milk samples from 169 goats in three farms (F1, F2 and F3) were analysed during an entire lactation (45, 75, 105, 135 and 165 days in milking DIM), to obtain renneting parameters, both from fresh milk and after storage with Bronopol and freezing at −20°C and −80°C. As regards fresh milk, mean values of clotting time were between 12·51 (45 DIM) and 13·29 min (105 DIM and F2), the curd firming time between 1·77 (45 DIM) and 2·15 min (F1) and curd firmness between 42·09 (165 DIM) and 49·55 mm (45 DIM). No statistical difference was recorded after storage. After regression analysis, all prediction models showed significance value at P<0·001 with the highest R2 value for clotting time, 0·710 (fresh vs. frozen milk at −20°C), and the lowest for clot firmness, 0·281 (fresh vs. frozen milk at −80°C). Results demonstrated that assessment of goat milk coagulation properties using the Formagraph method is also achievable after freezing or Bronopol addition.

The potential benefits on human health have prompted an interest in developing nutritional strategies for specifically increasing rumenic acid (RA) in ruminant milk. The aims of the present study were to (i) compare two dietary treatments with lipid supplements on milk yield and composition, (ii) measure the in vivo Δ9-desaturation of vaccenic acid (VA) to RA using 13C-labelled VA and (iii) determine the effect of the dietary treatments on this variable. Treatments were 90 g sunflower-seed oil (SO) per d or 60 g sunflower-seed oil and 30 g fish oil per d plus additional starch (SFO), in a grassland hay-based diet given to eight Alpine goats in a 2 × 2 cross-over design with 21 d experimental periods. Milk yield and composition were similar between treatments. Goats fed SFO had higher milk 6 : 0–16 : 0 concentration, lower milk ΣC18 concentrations and showed no effect on milk VA and RA, compared with SO. At the end of the experiment, intravenous injection of 1·5 g [13C]VA followed by measurements of milk lipid 13C enrichment showed that in vivo 31·7 and 31·6 % of VA was Δ9-desaturated into milk RA in the caprine with the SO and SFO treatments, respectively. The expression of genes encoding for Δ9-desaturase (or stearoyl-CoA desaturase; SCD1, SCD5) in mammary tissues and four milk Δ9-desaturation ratios were similar between treatments. In conclusion, the present study provides the first estimates of in vivo endogenous synthesis of RA (63–73 % of milk RA) from VA in goats, and shows no difference between the two lipid supplements compared.

Consumption of whole milk and related dairy products has decreased considerably as a result of negative aspects associated with the consumption of saturated fats. The main difference between the composition of goat milk and cow milk concerns the composition of the fat, that of goat milk containing a larger proportion of medium-chain triglycerides. The metabolic utilization of these compounds is fundamentally oriented towards their use as sources of energy, and they may even contribute to the synthesis of proteins. This study was carried out, using 40 rats at weaning, in order to determine whether, on the basis of their fat and protein composition, there is any difference between the nutritional utilization of the N and the energy from goat and cow milk. Eight animals were killed on arrival at the laboratory, and the rest were divided into four groups of eight animals and killed at the end of the experiment. Each group was given a different diet: diet 1 contained fat and protein from goat milk; diet 2 had fat from cow milk and protein from goat milk; diet 3 had fat from goat milk and protein from cow milk; diet 4 had fat and protein from cow milk. The animals were allowed to feed ad libitum for 30 d and a balance assay was performed during the final 7 d to determine N and energy utilization. At the same time and by the comparative slaughter method, the protein and fat deposition for each group was established. It was concluded that goat milk protein is more digestible than that of cow milk. Moreover, the metabolic utilization of digestible N was found to be dependent on the sources of both the protein and the fat in the diet; a higher degree of utilization was recorded for the digestible N obtained using diets with protein or fat from goat milk. Consumption of diets with goat milk fat led to a lower level of thermogenesis associated with protein oxidation and a higher one for that associated with fat oxidation, which in turn implied a protein-sparing effect of the goat milk fat. These results should be taken into account when deciding upon the type of goat milk to be used (whole, skim or semi-skim), in accordance with the dairy product to be produced from this milk.

We examined the heat stability, somatic cell count (SCC), pH, fat, protein and lactose content of milk from goats during the oestrous period, in order to investigate evidence of possible oestrus effects on milk physical and chemical properties. Goats free from mammary infections were ranked on average SCC from three tests so that they could be stratified randomly in pairs to synchronized oestrus or left as unsynchronized non-oestrus controls. The synchronisation consisted of insertion of an intravaginal progesterone-releasing device for 17 d, and introduction of the bucks the day of the device removal (D0). The repeated measurements analysis of variance model included the fixed effects of the experimental group (oestrus or control) and day and the corresponding interaction and also the random effect of doe. Reduced milk-heat stability, increased SCC, increased protein content and reduced pH were found in the milk samples of the oestrus group on D1, 2 and 3. The fat and lactose content of the milk was not affected by oestrus. These data indicate that the milk of goats during the mating period has reduced heat stability and, therefore, that dilution into bulk tanks should be recommended to avoid clotting when milk is intended for high thermal treatment.

The influence of pH (4·5–6·5), sodium chloride content (125–375 mM), calcium chloride content (10–30 mM), protein concentration (70–90 g/l) and lactose content on the gel hardness of goat whey protein concentrate (GWPC) in relation to the origin of the acid whey (raw or pasteurized milk) was studied using a factorial design. Gels were obtained after heat treatment (90 °C, 30 min). Gel hardness was measured using texture analyser. Only protein concentration and pH were found to have a statistically significant effect on the gel hardness. An increase in the protein concentration resulted in an increase in the gel hardness. GWPC containing 800 g/kg protein formed gels with a hardness maximum at the pHi, whereas GWPC containing 300 g/kg protein did not form true gels. Whey from pasteurized milk formed softer gels than whey from raw milk. A high lactose content (≈360 g/kg) also reduced the gelation performance of GWPC.

An experiment involving a feeding trial and a comparative slaughter was conducted to assess the body chemical composition and patterns of nutrient utilization in pre-ruminant Saanen goat kids. Thirty male kids weighing about 6 kg were divided into five equal groups, one of which was slaughtered as the reference group (G0). The remainder were randomly assigned to four feeding levels of 250, 290, 330 and 370 g goats’ milk per kg M0·75 per day and named as groups GI, GII, GIII and GIV, respectively up to about 15 kg live weight, after which they were slaughtered. Mean milk consumption per unit live-weight gain (LWG) (kg/kg), and daily LWG (g/day), for GI, GII, GIII, GIV respectively were: 13·5 and 110; 10·5 and 160; 10·2 and 180; and 10·3 and 200. Empty body weight (EBW) as a proportion of final live weight was 0·95 in the reference animals, and ranged from 0·80 to 0·88 in the treatment groups. The dry matter (DM) concentration in the empty body of kids increased as their age advanced, from 277 g/kg EBW (G0) to between 308 and 326 g/kg EBW (GI to GIV). The protein and fat concentration of LWGs increased with the level of feeding from GI (142 g crude protein (CP) and 75·5 g fat per kg LWG) to GIV (155 g CP and 109 g fat per kg LWG). Regression of energy retention (ER) on metabolizable energy (ME) intake resulted in an efficiency of ME utilization for body retention (k) of 0·72(± 006). ME requirement for maintenance was estimated as 458 kJ/kg M0·75 per day. Efficiency of nitrogen (N) utilization for growth and N requirement for maintenance were estimated as 0·66(±011) and 0·47 g/kg M0·75 per day, respectively.