Effect of daily oxytocin injection on milk yield and lactation length in sheep

Influence of Replacement Levels of Orange Waste Silage on Intake, Nutrient Digestion, Ruminal Fermentation and Milk Yield in Barki Goats

Exploring new alternative sources of feedstuffs can contribute to animal production sustainability in some Mediterranean regions in order to overcome the rising food demand. The influence of dietary replacement of wheat straw (WS) with orange waste silage (OWS) on nutrient intakes, apparent digestibility, ruminal fermentation and blood biochemical constituents and milk production of dairy goats were evaluated. Forty pregnant goats (46.30±1.6 kg BW) were housed in individual pens in a completely randomized design and fed (ad libitum) a TMR for 75 days period. Goats were assigned to four experimental diets with the forage amounts consisting of either WS as a control diet (1000 g WS/kg DM in the TMR), a 50:50 mixture of both WS and OWS (500 g WS and 500 g OWS/kg DM in the TMR), an orange waste silage (1000 g OWS/kg DM in the TMR) or corn silage as a positive control (1000 g CS/kg DM in the TMR). The DMI increased linearly (P<0.01), while fiber fractions intake decreased linearly (P<0.01) with increasing of OWS in the diet. Ruminal pH was increased quadratically (P<0.01), whereas NH3-N concentration and total protozoa abundance decreased quadratically (P<0.01) with increasing OWS in the diet. Ruminal acetate content was increased linearly (P = 0.012) by diet; whereas linear effects were observed on propionate and butyrate proportions (P<0.01) as OWS amount increased. Blood urea nitrogen (BUN), non-esterified free fatty acids (NEFA) and β-hydroxybutyrate (BHBA) levels decreased linearly (P<0.01) with ascending amounts of OWS. Serum glucose, BUN, NEFA and BHBA levels were lower (P<0.01) for goats fed the OWS diet than those fed the CS diet. Milk yield and milk nitrogen efficiency were linearly increased (P<0.01), whereas quadratic effects (P = 0.049) were observed on milk urea nitrogen content with increasing dietary OWS. In conclusion, the replacement of WS with OWS enhanced rumen fermentation and milk yield of late pregnant and early lactation Barki goats.

Minimally invasive biomarkers to detect maternal physiological status in sow saliva and milk

In this study, we aimed to validate existing plasma assays to measure biomarkers for maternal signalling in milk and saliva of lactating sows. These biological samples are minimally invasive to the animal and could give a physiological profile of maternal qualities available to their piglets. Sows were farrowed in a zero-confinement system, and their colostrum and milk samples were manually collected during naturally occurring let-downs (i.e. not induced) over the lactation period. Saliva sampling involved sows voluntarily accepting cotton buds to chew without restraint. Commercial kits designed for blood plasma were tested, and any modifications and results are given. We successfully measured total protein, cortisol, tumour necrosis factor-α (TNF-α) and oxytocin in pig milk and saliva and immunoglobulin G (IgG) in pig milk samples. We were unsuccessful at measuring relaxin and serotonin in these biological samples. We observed higher levels of biomarkers in milk than in saliva. The measurement of TNF-α in pig milk for the first time revealed increased levels with larger litters. This development will allow more detailed understanding of biomarkers in milk. There was also evidence that the minimally invasive technique of using saliva sampling did not interrupt natural oxytocin production around parturition.

The mammary gland in small ruminants: major morphological and functional events underlying milk production--a review

The importance of small ruminants to the dairy industry has increased in recent years, especially in developing countries, where it has a high economic and social impact. Interestingly and despite the fact that the mammary gland is the specialised milk production organ, very few authors studied the modifications occurring in the mammary gland through the lactation period in production animals, particularly in the small ruminants, sheep (Ovis aries) and goat (Capra hircus). Nevertheless, understanding the different mammary gland patterns throughout lactation is essential to improve dairy production. In addition, associating these patterns with different milking frequencies, lactation number or different diets is also of high importance, directly affecting the dairy industry. The mammary gland is commonly composed of parenchyma and stroma, which includes the ductal system, with individual proportions of each changing during the different periods and yields in a lactation cycle. Indeed, during late gestation, as well as during early to mid-lactation, mammary gland expansion occurs, with an increase in the number of epithelial cells and lumen area, which leads to increment of the parenchyma tissue, as well as a reduction of stroma, corresponding macroscopically to the increase in mammary gland volume. Throughout late lactation, the mammary gland volume decreases owing to the regression of the secretory structure. In general, common mammary gland patterns have been shown for both goats and sheep throughout the several lactation stages, although the number of studies is limited. The main objective of this manuscript is to review the colostrogenesis and lactogenesis processes as well as to highlight the mammary gland morphological patterns underlying milk production during the lactation cycle for small ruminants, and to describe potential differences between goats and sheep, hence contributing to a better description of mammary gland development during lactation for these two poorly studied species.

Effect of presence or absence of corpora lutea on milk production in East Friesian dairy ewes

The potential luteal effects on milk production were examined in dairy ewes that were not superovulated in contrast to studies using superovulated ewes. Lactating East Friesian crossbred ewes (n = 24) were synchronized using intravaginal progesterone (controlled intravaginal drug-releasing device), PGF2alpha, and gonadotropins. After ovulation, corpora lutea (CL) were counted via laparoscopy on d 4 and 11. On d 5, ewes received either saline (CLYES, n = 12) or PGF2alpha (CLNO, n = 12) to allow CL persistence (2.4 +/- 0.3 CL on d 11) or regression (0 CL on d 11), respectively. Each ewe received two CIDR d 5 to 18 to maintain high concentrations of plasma progesterone (P4) and to suppress estradiol (E2). Each ewe received PGF2alpha on d 18. Data were collected during three periods (pretreatment: d 0 to 5; treatment: d 6 to 18; posttreatment: d 19 to 25). Milk yield and milking time were recorded daily, milk samples were obtained for analyses of fat and protein, and blood samples were collected for P4 and E2 immunoassay. During treatment, CLYES ewes had higher milk yield (1.56 vs. 1.44 +/- 0.01 kg/d), milk fat (92.2 vs. 81.1 +/- 1.3 g/d), and milk protein (83.7 vs. 77.5 +/- 0.8 g/d) compared with CLNO ewes, respectively. Differences were maintained posttreatment, despite luteolysis in CLYES ewes. Estradiol concentrations did not differ between treatments and were low after d 5. Milk production was increased in East Friesian ewes in the presence of an average of 2.4 corpora lutea, an effect independent of estradiol.