The Mathematical description of lactation curves in dairy cattle

This review gives an overview of the mathematical modelling of lactation curves in dairy cattle. Over the last ninety years, the development of this field of study has followed the main requirements of the dairy cattle industry. Non-linear parametric functions have represented the preferred tools for modelling average curves of homogeneous groups of animals, with the main aim of predicting yields for management purposes. The increased availability of records per individual lactations and the genetic evaluation based on test day records has shifted the interest of modellers towards more flexible and general linear functions, as polynomials or splines. Thus the main interest of modelling is no longer the reconstruction of the general pattern of the phenomenon but the fitting of individual deviations from an average curve. Other specific approaches based on the modelling of the correlation structure of test day records within lactation, such as mixed linear models or principal component analysis, have been used to test the statistical significance of fixed effects in dairy experiments or to create new variables expressing main lactation curve traits. The adequacy of a model is not an absolute requisite, because it has to be assessed according to the specific purpose it is used for. Occurrence of extended lactations and of new productive and functional traits to be described and the increase of records coming from automatic milking systems likely will represent some of the future challenges for the mathematical modelling of the lactation curve in dairy cattle

Il benessere degli ovini e dei caprini: una speciale attenzione da parte della Regione Sardegna

Negli ovini e nei caprini, analogamente ai bovini, la lattazione rappresenta la fase fisiologica preponderante del ciclo produttivo, durante la quale un insufficiente livello di benessere si ripercuote sulla produzione quanti-qualitativa di latte. In questa fase il controllo dello stato sanitario della mammella, con mezzi diretti e/o indiretti, rappresenta un valido strumento per migliorare la gestione del processo stesso e, in ultima analisi, il benessere degli animali. Tenuto conto che le politiche comunitarie sono sempre più stringenti in materia di benessere animale, è importante che gli operatori del settori non percepiscano queste come imposizione ma come un’occasione di crescita professionale volta alla salvaguardia delle produzioni di qualità. E’ in quest’ottica che la Regione Sardegna ha strutturato un piano per il miglioramento del benessere dei piccoli ruminanti, premiando con un contributo in denaro gli allevatori che nei prossimi cinque anni si impegneranno ad adottare opportune tecniche di allevamento finalizzate alla riduzione del contenuto in cellule somatiche del latte, in quanto sono una diretta espressione dello stato sanitario della mammella. Assieme a queste azioni dirette la Regione Sardegna ha previsto un piano di formazione degli addetti al settore in modo tale da ridurre gli effetti negativi del fattore umano sul benessere animale

Excretion pattern of aflatoxin M1 in milk of goats fed a single dose of aflatoxin B1

The feedstuffs used in dairy animals must be able to give consumers confidence about the wholesomeness of milk with regard to aflatoxin contamination. The aim of this study was to determine the excretion patterns of aflatoxin M(1) (AFM1) in the milk of dairy goats fed a single dose of pure aflatoxin B(1) (AFB1), which can occasionally occur if feeds are infected by hot-spot growth of molds that produce aflatoxins. Five dairy goats in midlactation were administered 0.8 mg of AFB1 orally. Individual milk samples were collected for 84 h after AFB1 dosage. Aflatoxin M(1) was found in milk in the highest concentration. In all goats, AFM1 was not detected in milk before AFB1 administration, but was detected in the first milking following AFB1 administration. The excretion pattern of AFM1 concentration in milk was very similar in all goats even if the values of the concentration differed between animals. The peak values for AFM1 concentration in milk was observed in milk collected during the milking at 3 and 6h. After the peak, the AFM1 in milk disappeared with a trend that fitted well a monoexponential decreasing function, and the toxin was not detected after 84 h. Only about 0.17% of the amount of AFB1 administered was detected as AFM1 in milk, and about 50% of this was excreted in the first liter of milk yielded after AFB1 intake. Correct procedures to prevent growth of molds, and consequent AFB1 contamination, on the feedstuffs for lactating goats represent the key to providing consumers a guarantee that milk is not contaminated by AFM1

Monitoring the on-farm welfare of sheep and goats

Schemes for on-farm welfare assessment in sheep and goats are not yet available. Factors responsible for this lack of availability are discussed in the first part of this review. Requisites for reliable methods of welfare assessment to be used in sheep and goat farms are discussed, taking into account the peculiarities of the small ruminant production systems in terms of flock management and farm location. Some housing parameters related to structures, design and micro-environment are reviewed and could be included in schemes of welfare assessment on farm. Human-animal interaction, health status of the animals in terms of body condition scoring, skin and hair conditions, lameness and injuries, and management practices in relation to cleanliness, animal handling and moving, milking procedures and abnormal behaviours, are proposed as potential animal-based indicators. When available, validity, reliability and feasibility of the proposed parameters are discussed. The voluntary adhesion to welfare standards in Sardinia and the application of a scientifically validated protocol in Basilicata are reported as examples of practical experiences

Machine milking management and milk nitrogen fractions in primiparous ewes

Little work has been carried out on management techniques to reduce stress of first machine milking in ewes. The aim of this work was to evaluate the effect of milking parlour training before weaning on sheep milk yield and milk protein fractions. One week before weaning, an experimental group (EG) was introduced into the machine milking parlour and hand-milked once a day, to adapt them to the new environment and noise of the milking machine, while a control group (CG) was hand-milked once a day in a traditional fold parlour until weaning. After weaning, both groups were machine milked, separately, twice a day in the milking parlour. Milk yield and nitrogen fractions were recorded for the first 10 days of machine milking. Differences between samplings within group were observed for all parameters considered. Only on the first day of machine milking, differences between groups occurred for total nitrogen, total protein and casein. Higher content of nitrogen fractions in the milk of EG was due to its lower milk production. In fact, daily production of nitrogen fractions was higher in CG than in EG. High variability for most parameters was observed during the first 5 days of machine milking in both groups. A week of training to machine milking parlour was not enough to reduce the negative effects of weaning and machine milking stresses on primiparous ewes. (interaction?

Coscienza degli animali e interazione uomo animale

Il benessere degli animali negli allevamenti zootecnici ha ormai grande importanza non soltanto sotto l’aspetto etico ma anche come fattore in grado di influenzare la qualità dei prodotti destinati all’alimentazione umana. La ricerca, tuttavia, mostra ancora evidenti carenze sulla valutazione dello stato di benessere degli animali sia per la mancanza di parametri oggettivi, sia gli studi limitati e concentrati sugli aspetti legati agli animali, che hanno trascurato fattori importanti come l’interazione uomo-animale e le capacità cognitive degli animali. E’ accertato che esistono stretti rapporti tra il comportamento dell’uomo con gli animali e le risposte che essi hanno verso l’uomo e la produttività. Gli animali che hanno paura dell’uomo hanno più probabilità di manifestare stress in sua presenza comportando talvolta immunodepressione con serie conseguenze sulla loro salute. Le ricerche di tipo etologico e cognitivo possono contribuire al benessere fornendo evidenze obiettive sul modo in cui gli animali reagiscono alle condizioni di cattività negli allevamenti e all’interazione con l’uomo. Gli indicatori biologici non consentono da soli di valutare sempre lo stato di benessere degli animali, infatti, non è inusuale che un animale presenti delle anormalità comportamentali senza mostrare nel contempo alcuna variazione fisiologica riconducibile ad uno stato di stress, il che rende difficile decidere quali siano gli indicatori più affidabili

The Effect of the utilization of a high fibre pelleted feed on milk yield and composition in dairy sheep

Twenty Sardinian lactating ewes were divided in four groups (A, B, C, D) and fed with four diets, obtained mixing a pelleted fibre integrator (PFI) and a normal pelleted concentrate (NPC) in different proportions (NPC/PFI: A = 27/73; B = 42/58; C = 58/42; D = 73/27). The intake was 123, 122, 114 and 135 g of DM per kg of metabolic weight. The ewes were able to choose between the two type of pellets. The chewing time per kg of DM decreased with the reduction of PFI content in the diet. The ewes were always able to maintain a regular ruminal activity. There were no significant differences in the milk yield, milk fat content, SCC and body weight variations, while the milk protein content was higher in the group B

Shearing influences the milk fatty acid profile of dairy ewes

In Mediterranean areas shearing is commonly performed during late spring and, therefore, ewes may be exposed to cold stress especially during the night. Short-term periods of cold exposure can increase hepatic glucose production, decrease insulin secretion and increase fat catabolism and plasma non-esterified free fatty acids (NEFA) concentration. These metabolic adaptations to cold exposure can increase the mammary uptake of long-chain fatty acid from plasma. The present study aimed to investigate the metabolic response of dairy ewes to shearing by monitoring their milk fatty acid (FA) profile. Twelve 2-4-year-old Sarda ewes, in mid-late lactation, were used. The trial lasted from 30th May to 9th June 2006. The pre-experimental period (pre-shearing, PrS) was from 30th May to 5th June (shearing day), being followed by the experimental period (post-shearing, PoS) until 9th June. On shearing day, the flock was divided in two groups (6 ewes each) which were then managed differently: non-confined group (NCG) and confined group (CG) which was kept in a sheepfold during the night. Four samplings during PrS and other four during PoS periods were performed. During the trial, ewes were fed concentrate at 1000g/d per head, during the two daily milking, and hay ad libitum, and grazed on green clover (3h/day). Daily milk production was recorded and daily milk samples were collected for analysis of fat content and FA profile. Shearing did not influence milk yield but increased significantly milk fat content (6.37 vs. 6.94% for PrS and PoS, respectively; P<0.01). Ewes confinement during the night did not affect milk yield and its fat content. Shearing modified significantly the FA profile of milk. The concentration of C8, C10, C12 and C16 increased significantly from PrS to PoS. On the other hand, the content of long-chain FA (>C18:0) did not change between PrS and PoS (46.26 vs. 46.40mg/100g of FAME, respectively). These results suggest that the increase of milk fat after shearing was related to the increase of the main FA synthesized by the mammary gland. However, the unexpected increase in the synthesis of short- and medium-chain FA after shearing suggests that these animals were not subjected to cold stress. Therefore, the mechanism involved in the modification of the FA profile caused by shearing in dairy ewes should be elucidated

Analysis of MC1R polymorphism in Sardo-Modicana cattle

Coat colour has been a topic of interest for both breeders and geneticists. Currently most cattle breeds are identified by their coat colour. In mammals, red/yellow and black/brown colours are determined by the distribution of two pigments: pheomelanin and eumelanin. The relative amounts of these pigments are primarily controlled by two loci, namely Extension (E) and Agouti (A). Extension gene encodes a seven trans-membrane domain receptor called Melanocortin 1 Receptor (MC1R). Activation of MC1R causes the production of eumelanin, whereas its inhibition leads to the production of pheomelanin. In cattle, three main alleles are known for MC1R gene: i) E+ (wild type), ii) ED (dominant black), and iii) e (recessive red). Mutations in coat colour genes have already been utilized for breed traceability of livestock products. Sardo-Modicana is an old local breed that experienced a gradual decrease in numbers as a result of the mechanization of agriculture. Following the recent tendency of market for typical products, there is a renewed interest for cheese and meet produced by this breed. Traceability protocols for this breed will be useful to guarantee the consumers and protect Sardo-Modicana breeders. The aim of this investigation was to analyse MC1R polymorphism in Sardo-Modicana cattle breed and evaluate if these DNA markers can be useful for product traceability in this breed. A total of 60 genomic DNA samples from Sardo-Modicana cattle collected in seven farms in the Monti Ferru area of western Sardinia were analysed by PCR-RFLP method. DNA was amplified using specific primers designed on the base of the bovine sequence from GenBank Acc. no. U39469. The obtained 402 bp amplicons were separately digested with restriction endonucleases MspA1l to score allele ED and Msp1 for allele e respectively. The fragments were run on 2.5% agarose gel stained with Ethidium Bromide. Results on Sardo-Modicana breed highlighted an almost exclusive occurrence of wild type allele except in one animal that resulted heterozygous E+/e. A larger number of animals of the same or other breeds farmed in Sardinia is needed to clarify if the locus polymorphism for MC1R is a valid DNA marker for the identification of Sardo-Modicana products

Effect of extruded linseed supplementation on blood metabolic profile and milk performance of Saanen goats

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