Third Week Of Lactation Research Articles

Oral administration of domperidone in the first or third week of lactation: Effects on prolactin concentrations and mammary gene expression in sows and piglet growth

The scope of the present study is endocrine and metabolic control of sow lactation. This project aimed to determine the impact of increasing prolactin concentrations via oral administration of the dopamine receptor antagonist domperidone in the first or third week of lactation in sows. Effects on sow hormonal and metabolic status, lactational performance, and gene expression in mammary epithelial cells were determined. Primiparous sows were divided in 3 treatments: 1) 10 mL of vehicle (table syrup) per os twice daily during the first and third weeks of lactation (Control, CTL, n = 23), 2) 0.5 mg/kg of domperidone per os twice daily during the first week of lactation (LACT1, n = 23), or 3) 0.5 mg/kg of domperidone given per os twice daily during the third week of lactation (LACT3, n = 22). Treated sows also received 10 mL of the vehicle twice daily during the other treatment period. Litter size was standardized to 12 ± 1 and piglets were weighed at birth, 24 h, and on d 8, 15, 22 (weaning), 35, and 56. Sow feed intake was recorded daily. Representative milk samples were obtained on d 7 and 21 of lactation for compositional analyses, and milk fat globules were used to measure mRNA abundances of various genes. Jugular blood samples were obtained from sows on d 1, 7, 14, and 21 of lactation to measure concentrations of prolactin, IGF-1, insulin, urea, and FFA. Concentrations of prolactin were increased (P < 0.01) at the end of the 7-d treatment period with domperidone, whether imposed in the first (LACT1) or third (LACT 3) week of lactation. No other blood variables were affected by treatments and neither was milk composition (P > 0.10). Sow BW, backfat thickness, or feed intake were not altered by treatments (P > 0.10), but piglet BW tended to be greater in litters from LACT3 compared with CTL sows on d 22 and 35 (P ≤ 0.10). Gene expression of EGF in milk fat globules tended to be (LACT1, P < 0.10) or was increased (LACT3, P < 0.05) after treatment, and the effect in LACT1 sows was maintained until d 21 of lactation. The mRNA abundance of SPP1 was increased (P < 0.05) in LACT1 vs CTL sows on d 7, and that of 3 major milk proteins tended to be (CSN1S2 and WAP, P < 0.10) or was greater (LALBA, P < 0.05) in LACT3 vs CTL sows on d 21 of lactation. Oral administration of domperidone during the first or third week of lactation increased prolactin concentrations and altered mRNA abundances of selected genes in milk fat globules. Yet, only the LACT 3 treatment positively affected piglet performance.

The Role of PRLR Gene Polymorphisms in Milk Production in European Wild Rabbit (Oryctolagus cuniculus).

One of the problematic points of rabbit breeding is that the nutritional requirements of the kits are not fully satisfied by the does' milk production from the third week of lactation onwards. The prolactin receptor gene has a significant effect on reproductive processes, and its polymorphisms have been associated with milk production in several species (cattle, goats, sheep, and buffalo). The European wild rabbit (Oryctolagus cuniculus), has a more diverse genetic background compared to domesticated lines. In the course of our study, sequencing of the 1210 bp long segment of the PRLR gene promoter region was accomplished. We detected four point mutations (SNP1-407G > A, SNP2-496G > C, SNP3-926T> and SNP4-973A > C) and one microsatellite at position 574. In our population, the four SNPs were segregated into four genotypes: AACCCCCC, GGGGTTAA, AAGGTTAC, and GGGGTCAC. Our results show that the genotype in the homozygous form is associated with higher milk production (1564.7 ± 444.7 g) compared to the other three genotypes (AACCCCCC 1399.1 ± 326.8 g; GTGACCTT 1403.8 ± 517.1 g; GGGGTCAC 1220.0 ± 666.2 g), and the short microsatellite repeat (167 bp) also coincides with significantly higher milk production (1623.8 ± 525.1 g). These results make the marker-assisted selection possible also for domesticated lines.

Effect of Different Ambient Temperatures on Reproductive Outcome and Stress Level of Lactating Females in Two Mouse Strains.

Simple SummaryThe optimal temperature for laboratory mice has been under discussion for some time. Current standard temperature is 20 °C–24 °C but it has been suggested to elevate the standard to 30 °C, which is the thermoneutral zone for mice. In this study, the effect of different cage temperatures (20 °C, 25 °C, 30 °C) on reproduction and stress hormone metabolite excretion was evaluated in lactating females of two commonly used mouse strains. Pup loss was higher, and weights of mothers and pups were reduced at 30 °C compared to the lower temperatures. In addition, pups showed increased tail length at weaning under the high temperature (30 °C). There was no difference in stress hormone metabolite excretion in mice between temperature groups. We could not show any detrimental effects of the lower or higher cage temperature on stress hormone metabolite excretion, but found decreased reproductive outcome under the higher temperature.Ambient temperature is an important non-biotic environmental factor influencing immunological and oncological parameters in laboratory mice. It is under discussion which temperature is more appropriate and whether the commonly used room temperature in rodent facilities of about 21 °C represents a chronic cold stress or the 30 °C of the thermoneutral zone constitutes heat stress for the animals. In this study, we selected the physiological challenging period of lactation to investigate the influence of a cage temperature of 20 °C, 25 °C, and 30 °C, respectively, on reproductive performance and stress hormone levels in two frequently used mouse strains. We found that B6D2F1 hybrid mothers weaned more pups compared to C57BL/6N mothers, and that the number of weaned pups was reduced when mothers of both strains were kept at 30 °C. Furthermore, at 30 °C, mothers and pups showed reduced body weight at weaning and offspring had longer tails. Despite pronounced temperature effects on reproductive parameters, we did not find any temperature effects on adrenocortical activity in breeding and control mice. Independent of the ambient temperature, however, we found that females raising pups showed elevated levels of faecal corticosterone metabolites (FCMs) compared to controls. Peak levels of stress hormone metabolites were measured around birth and during the third week of lactation. Our results provide no evidence of an advantage for keeping lactating mice in ambient temperatures near the thermoneutral zone. In contrast, we found that a 30 °C cage temperature during lactation reduced body mass in females and their offspring and declined female reproductive performance.

PSXVI-13 Study of migration of antigen-presenting cells in the tissue of the lactating mammary gland under the influence of staphylococcal vaccine

Abstract Dairy cow mastitis is widespread in various countries. Data from researchers around the world show that Staphylococcus aureus is one of the most common causative agents of mastitis. One of the methods of preventing staphylococcal infection is the introduction of a staphylococcal vaccine containing a complex of thermostable antigens extracted from microbial cells of S. aureus. In connection with the great urgency of this problem, we set the task to study the effect of staphylococcal vaccine on the migration of macrophage cells in the tissue of the lactating mammary gland. For the experiment, two groups of pregnant mice were formed, 15 individuals in each. Animals from the experimental group were injected subcutaneously with staphylococcal vaccine at a dosage of 0.2 ml, once 5 days before delivery. The selection of pathological material was carried out in three stages at the beginning of the first second and third weeks of lactation. Each time, 5 mice were selected from each group in accordance with the bioethics standards. From the material obtained, histosections were made with hematoxylin-eosin staining.In histosections, cells of the macrophage range were identified and counted in one hundred fields of view. We took into account cells that were defined by morphology as tissue macrophages, as well as dendritic cells. In the experimental group on the first, second and third weeks of lactation, the average number of macrophages was 69.6±2.07; 78.2±2.38 and 50.8±2.38 cells, in the control group at the same time - 38.3±2.51; 47.3±1.52 and 23.3±1.52 cells, respectively. The results obtained show an effective migration of antigen-presenting cells in the breast tissue, which is confirmed by higher rates in the experimental group by 1.7–2.2 times at all periods of the study (P &amp;lt; 0.05). The highest concentration of macrophages was found in vaccinated mice in the second week of lactation.

Early breast expression for very low birth infants admitted to neonatal intensive care unit: the challenges of cesarean deliveries

Aim of the study In preterm infants, the use of human milk is associated with unique benefits. However, successful breast feeding rates and prolonged breastfeeding duration is often reduced in preterm infants. Nevertheless, early initiation of breast expression after birth is believed to be one of the major variables that should improve the odds of successful breastfeeding. Hence, we aimed to assess correlation between timing of milk expression initiation and volume produced in regards to mode-of-delivery. Materials and methods Prospective, observational study. Mothers delivering infants weighing < 1500 g measured 24-h milk volumes on days 1–7, 14, and 21. Results Mothers delivering vaginally (N = 11) expressed milk sooner (3.82 ± 5.03 h) than mothers in the cesarean group (N = 42; 11.5 ± 9.1 h). There were no significant differences in daily number of expressions (i.e. day 1 3.6 ± 1.6 versus 2.5 ± 2.1, p = .125) or daily volume (i.e. day 1 – 7.5 ± 6.1 ml versus 11.6 ± 22.9 ml, p = .563), until day 6 from which, both were lower in the cesarean group (i.e. day 21 – number − 6.0 ± 1.3 versus 4.6 ± 1.7, p = .029; volume – 796 ± 465ml versus 435 ± 368ml, p = .018). Expressed volume initially did not correlate with earlier expression, however, latter expressed volume inversely correlated with earlier expression. In multivariate-analysis, mode of delivery, gestational age, and daily number of expressions were correlated with volumes on day 21 (p = .001). Conclusions Earlier human-milk expression is related to volumes on the second and the third week of lactation. This is overwhelmed by delivery mode, and by frequent milk expression from day 2. When early milk expression is not possible, more frequent milk expression might help increasing volumes.

The Effects of Energy Intake During late Pregnancy on Lamb Birth Weights and Lactation of Nigerian Dwarf Sheep

EIGHTEEN Nigerian Dwarf ewe lambs about eight months of age and weighing between 15 and 20 kg were divided into three groups, A, B, and C, and fed diets supplying 75, 100 and 125% of the ARC energy standards (1965) from the 15th week of pregnancy through lactation. Mean daily intakes during the last seven weeks of pregnancy were: dry matter 569, 748 and 826g: digestible organic matter 260, 496 and 593; and calculated metabolizable energy 0.99, 1.81 and 2.16 Mcal for groups A, B and respectively. The daily intakes during lactation were: 660, 748 and 857g of dry matter; 287, 593 and 690g of digestible organic matter and 1.05, 2.16 and 2.51 Mcal of calculated metabolizable energy for groups A, B and C respectively. Mean daily liveweight gains during the last seven weeks of pregnancy were 14.2, 99.0 and 90.0g and during lactation — 43.0, 7.9 and 10.4g for groups A, B and respectively, the differences being highly significant (P &lt;0.01). Mean birth weights of lambs were 1.18, 1.78 and 1.82kg for groups A, B and C respectively, the differences not being significant. Weight gains of lambs were highly significantly correlated with milk yield of their ewes. During a 10-week lactation period the differences in milk yields were highly significant between groups, with average daily yields of 312, 480 and 533g, for A, B and respectively. Peak yields were 481, 697 and 670 g for the respective groups between the second and third weeks of lactation. The mean values for milk composition were: fat, which remained relatively constant throughout lactation, 6.00, 6.36 and 6.40%; protein 4.82, 5.63 and 5.78%; lactose 4.15, 4.30 and 4.34%; total solids, which showed no definite trends during lactation, 15.98, 16.88 and 16.95%; and gross energy, which decreased with advancing lactation, 6.12, 6.18 and 6.38kcal/g for groups A, B and C respectively, the differences not being significant.

Impact of milk and nutrient intake of piglets and sow milk composition on piglet growth and body composition at weaning

The main objective of this study was to evaluate the impact of milk intake, milk composition, and nutrient intake on piglet growth in lactation and body composition at weaning. To evaluate the body composition of piglets, data from one experiment (44 Danish Landrace × Yorkshire × Duroc piglets) were used to develop prediction equations for body pools of fat, protein, ash, and water based on live weight and deuterium dilution space (exp. 1). Furthermore, a total of 294 piglets (Danish Landrace × Yorkshire × Duroc) from 21 sows of second parity were included in a second experiment (exp. 2). In exp. 2, piglet live weight was recorded on days 3, 10, 17, and 25 of lactation. On the same days, the milk intake and body composition were measured, using the deuterium oxide (D2O) dilution technique. Piglet weight gain was highly positively correlated with the intake of milk and the intake of milk constituents each week and on an overall basis having r values ranging from 0.65 to 0.93 (P < 0.001). When evaluating regressions for piglet growth, the milk intake in combination with the milk protein concentration explained 85% and 87% of the total variation in piglet gain in the second and third week of lactation, respectively, whereas milk intake was the only predictor of piglet gain in the first week of lactation explaining 81% of the variation. Fat, protein, and energy retention rates were all highly positively correlated with the daily intake of milk and intake of milk nutrients with r values ranging from 0.76 to 0.94 (P < 0.001). Piglet gain and retention rates were rather weakly correlated with the milk composition with r values ranging from 0.01 to 0.50 (being either negative or positive). Curvilinear response curves were fitted for live weight gain and body fat content at weaning in response to milk protein concentration, showing that live weight gain was slightly greater and body fat content was slightly lower at 4.9% milk protein, but it should be emphasized that the quadratic effects did not reach significance. Body fat content at weaning was positively related with the intake of milk (R2 = 0.44, P < 0.001) and milk fat (R2 = 0.46, P < 0.01). In conclusion, milk intake had a major impact on the piglet growth rate, and milk fat intake greatly influenced the body fat percentage at weaning, whereas milk composition per se only played a minor role for these traits.

Effect of using trace minerals (copper, zinc, selenium, and manganese) and vitamins A and E on the metabolic profile of Holstein cows in the transition period

The aim of this study was to assess the metaphylactic effect of subcutaneous doses of trace minerals (copper, zinc, selenium, and manganese) and vitamins A and E on biochemical (NEFA, BHBA, fructosamine, urea, triglycerides, HDL, and calcium) and hormonal parameters (cortisol, insulin, and IGF-1) of Holstein cows in the transition period. Sixty animals kept in a semi-confinement system, with an average production of 22 liters of milk per day (Farm 1) and 24 liters of milk per day (Farm 2) and a diet according to NRC (2001) with a low metabolic challenge, were divided into two groups: a treatment group, supplemented with trace minerals and vitamins (MTVG) (n=30), and a control group (CG) (n=30). The collection of blood samples was performed at the moments M1 (21 days prepartum), M2 (14 days prepartum), M3 (7 days prepartum), M4 (parturition day), M5 (7 days postpartum), M6 (14 days postpartum), and M7 (21 days postpartum). The experimental design was a randomized block design and the data were submitted to analysis of variance with repeated measures in time within the random variable cow. Differences were considered significant at 5% significance level and trend at 10% level. No difference was observed between treatment and the interaction treatment × day in the assessed parameters. However, some variables showed a significant difference of day. NEFA levels (P &lt; 0.0001) were higher on the parturition day. BHBA concentrations were higher after parturition (P=0.0031), with a peak at the third week of lactation. Fructosamine showed increasing values until the parturition day (P=0.0373), in which higher concentrations were observed. Average values of HDL were higher at 21 days postpartum (P &lt; 0.0001). Triglycerides levels remained high during the prepartum period but showed a sudden drop on the parturition day (P &lt; 0.0001), with lower values postpartum. Regarding serum calcium and IGF-1, lower values were observed on the parturition day (P &lt; 0.001) for both parameters. Cortisol presented a difference regarding day, with higher values on the parturition day (P=0.0151). Thus, the use of trace minerals and vitamins A and E in animals with an adequate body score and low metabolic challenge presents a low response to biochemical and hormonal parameters.

Lactoferrin and IgG levels in ovine milk throughout lactation: Correlation with milk quality parameters

The aim of this work has been to determine the levels of lactoferrin and IgG in ovine milk during the two first months of lactation and to compare with some milk quality parameters. Milk samples were collected from ewes of an Assaf flock. The levels of lactoferrin were determined by radial immunodiffusion. For this purpose, lactoferrin was isolated from ovine milk by chromatographic methods and polyclonal antibodies against it were obtained in rabbits. IgG levels were determined by a commercial sandwich ELISA. The mean concentration value of lactoferrin at the first day of lactation was 0.74 mg/ml and that for IgG of 9.25 mg/mL. The levels dropped sharply during the first three days of lactation and at the third week of lactation, the concentration in mature milk was of 0.07 mg/ml and 0.25 mg/ml for lactoferrin and IgG, respectively. There was no correlation between the levels of lactoferrin and IgG concentrations in ovine milk samples with those of total protein and bacterial count. A low positive correlation between lactoferrin and somatic cell counts (SCC) was found, which was more evident when samples were classified according to SCC levels. However, no significant differences were found with respect to IgG levels in milk samples, for high or low levels of SCC. Consequently, it seems that only high lactoferrin levels could be used as an indicator of subclinical mastitis.

EFFECT OF CONSUMPTION OF HIBISCUS SABDARIFFA AND AZADIRACHTA INIDCA PRENATALLY AND POSTNATALLY ON MILK CREAMATOCRIT AND EARLY GROWTH OF OFFSPRING

Background: Aqueous extracts of Hibiscus sabdariffa Linn. (HS) and Azadirachta indica A. juss (AI) are widely used in Nigeria for medicinal purposes and have been shown to affect postnatal growth of offspring. Breast milk creamatocrit is a simple accurate inexpensive technique and useful measure of lipid and energy content of breast milk. No data has shown effects of these extracts on breast milk creamatocrit and early postnatal growth of offspring. This study was designed to investigate effects of HS and AI on breast milk creamatocrit and early postnatal growth of offspring.&#x0D; Materials and Methods: 40 pregnant rats weighing 150-200g were used for this study. They were divided into control, HS and AI groups. These groups were subdivided into two of low and high doses. Administration was by gavage and commenced on day 1 of pregnancy and ended on postnatal day 21. Litter weight and length were recorded at birth, postnatal days 7-21. Breast milk was collected from 4 dams in each group at postnatal days 7-21 for milk creamatocrit.&#x0D; Results: Results showed that aqueous extract of HS and AI caused progressive increase in milk creamatocrit during lactation. This increase peaked greatly in the third week of lactation. There was also a progressive increase in BMI of pups in extract treated group that became significantly greater at weaning.&#x0D; Conclusion: In conclusion, consumption of aqueous extracts of HS and AI during pregnancy and lactation may accelerate the postnatal growth of the offspring through mechanisms that may depend on increased breast milk creamatocrit.

Influence of rumen-protected choline on blood red-ox potential and biochemical biomarkers of dairy cows during the transition period

The aim of this study was to determine the serum oxidative status, antioxidant capacity, and oxidative stress index, as well as aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatinine profiles, of dairy cows fed rumen-protected choline during the transition period. A total of thirty dairy cows allotted to one control and two experimental groups (10 animals per group) were fattened from 3 weeks prior to the expected calving date until 3 weeks postpartum. The control group was fed a basal diet, and treatment groups 1 and 2, were fed a basal diet containing 60 g/head/day and 120 g/head/day or rumen-protected choline, respectively. Serum total antioxidant status (TAS) levels for the control group and treatment groups 1 and 2 at the time of parturition were 0.56±0.029ab, 0.45±0.028b, and 0.59±0.036a, respectively. The differences between the groups were statistically significant (P&lt;0.05). Rumen-protected choline supplementation did not have a significant effect on TAS levels in the third week before parturition and in the first and third weeks of lactation. There were no significant differences (P&gt;0.05) between the groups in terms of total oxidative status (TOS), oxidative stress index (OSI) or creatinine levels. Serum ALT levels were significantly different (P&lt;0.05) between the groups at parturition and in the first week of lactation, but not significant (P&gt;0.05) for the other periods. In addition, the serum AST level was significantly different (P&lt;0.05) between the groups in the first and third weeks of lactation, but not significantly different (P&gt;0.05) for the other periods. After removing the effect of groups, time-dependent changes were significant (P&lt;0.001) for all parameters. The highest values for TAS, TOS and OSI were obtained in the third week before parturition. The values for these parameters decreased during parturition and after the postnatal period. The lowest values for serum ALT and creatinine occurred at parturition. Rumen-protected choline supplementation did not have a significant effect on serum TAS and TOS levels during the transition period. There is a need for further studies of animals with known metabolic profiles, malnourished animals, and those with high milk yields or metabolic disorders.

Dietary ractopamine supplementation during the first lactation affects milk composition, piglet growth and sow reproductive performance

Excessive mobilization of body reserves during lactation delays the return to reproductive function in weaned primiparous sows. This study tested the hypothesis that supplementing the lactation diets of first-parity sows with ractopamine hydrochloride would reduce maternal weight loss and improve subsequent reproductive performance. Gestating gilts were allocated to one of two treatment groups (n=30 sows/treatment), with one group fed a standard lactation diet (2.5g/Mcal LYS: DE) throughout lactation (CTRL), whereas the treatment group received the standard lactation diet supplemented with 10mg/kg ractopamine hydrochloride (RAC) from d 1 to 13 of lactation and 20mg/kg RAC from d 14 of lactation until artificial insemination (AI). Weaning occurred on d 21 of lactation, with AI occurring at the first post-weaning estrus. Compared to CTRL, RAC supplementation decreased (P<0.05) liveweight loss between d 13 and 20 of lactation (4.3±0.90 versus 1.3±0.96kg), and tended to increase (P=0.06) the number of second litter piglets born alive (9.5±0.52 versus 8.1±0.74). Treatment (RAC versus CTRL) reduced milk protein levels on d 13 and 20 of lactation (P<0.05), and piglet weight gain between d 13 and 20 of lactation (260±0.01 versus 310±0.01g/day, P<0.01). In conclusion, it is evident that dietary RAC altered milk composition and stimulated conservation of maternal body reserves during the third week of lactation, resulting in a beneficial effect on subsequent reproductive performance.

Effects of Dietary Supplementation of Oregano Essential Oil to Sows on Oxidative Stress Status, Lactation Feed Intake of Sows, and Piglet Performance.

Fifty-four multiparous large white sows were used to determine the effects of supplementing oregano essential oil (OEO) to the gestation and lactation diets on oxidative stress status, lactation feed intake, and their piglet performance. Two groups were fed diets with (OEO; n = 28) or without (Control; n = 26) supplemental 15 mg/kg OEO during gestation and lactation. The serum levels of reactive oxygen species (ROS) (P < 0.05), 8-hydroxy-deoxyguanosine (8-OHdG) (P < 0.05), and thiobarbituric acid reactive substances (TBARS) (P < 0.05) were higher during gestation (days 90 and 109) and lactation (days 1 and 3) than in early gestation (day 10). Compared with the control group, the OEO diet significantly reduced sows' serum concentrations of 8-OHdG (P < 0.05) and TBARS (P < 0.01) on day 1 of lactation. The OEO diet increased the sows' counts of faecal lactobacillus (P < 0.001) while reducing Escherichia coli (P < 0.001) and Enterococcus (P < 0.001). In the third week of lactation the treatment tended to increase sow's feed intake (P = 0.07), which resulted in higher average daily gain (P < 0.01) of piglets. Our results demonstrated that there is an increased systemic oxidative stress during late gestation and early lactation of sows. The OEO supplementation to sows' diet improved performance of their piglets, which may be attributed to the reduced oxidative stress.

Vliv přídavku propylenglykolu na tělesnou kondici krav, jejich mléčnou užitkovost a kvalitu mleziva

The research was executed on 24 high yield dairy cows divided into three groups (n = 8). There was the control group (I) that the propylene glycol wasn’t given to cows, group II – the cows received 250 ml/day/per head of the propylene glycol, and the group III ─ the cows received 500 ml/day per head of the propylene glycol. The preparation was administered to cows per os beginning from 2 weeks before parturition to the end of the third week of lactation. During the research the condition of animals was estimated by BCS method, the daily yield was recorded, and analyses of the milk and colostrum composition were performed. The propylene glycol lightened the decrease of cows’ condition during entering at the peak of lactation. The higher dose (500 ml) was more profitable, because it had an influence on the content of the colostrum components, low urea level in milk as well as on daily yield, which was higher of about 3.64 kg while the preparation was given, in comparison to the control group. In the 3rd week of lactation the low level of somatic cells in milk of cows that received the preparation was stated. In conclusion, our study revealed a great positive effect of propylene glycol given to the cows shortly before and after parturition on their body condition and a less significant effect on colostrum quality and milk yield.

Fat and whey supplementation influence milk composition, backfat loss, and reproductive performance in lactating sows

This study investigates the effects of microencapsulated fat (FAT) and whey protein (WHEY) supplementation on the milk composition, backfat loss, and reproductive performance in lactating sows. A total of 144 sows were divided according to their backfat thickness at farrowing into three groups, i.e., low (12.0-16.5mm, n = 33), moderate (17.0-21.5mm, n = 78), and high (22.0-24.5mm, n = 33). The lactation diet was divided into three types, i.e., a control diet (CONTROL, n = 50), a diet supplemented with FAT (n = 48), and a diet supplemented with WHEY (n = 50). Pooled milk samples were collected at the second and third week of lactation. On average, the sows lost backfat 23.5% during lactation. The backfat loss during lactation was 24.5, 22.7, and 22.8% in sows fed with CONTROL, FAT, and WHEY diets, respectively (P > 0.05). Supplementation of FAT increased the percentage of fat in the sow's milk compared to the CONTROL (9.1 and 8.4%, P = 0.022). For sows with low backfat, FAT and WHEY supplementation increased the average daily gain of piglets compared to the CONTROL (244, 236, and 205g/days, respectively, P < 0.05). For sows with high backfat, the sows receiving the CONTROL diet had a higher total piglet mortality than those that received FAT or WHEY (28.1, 14.1, and 13.0%, respectively, P < 0.05). It could be concluded that supplementation of FAT in the diet of sow during lactation significantly enhanced the fat content in the sow's milk, improved the piglet's daily weight gain, and reduced piglet mortality.

Relationship between energy status and fertility in Czech Fleckvieh cows

The aim of this study was to confirm that a negative energy balance expressed by declining body condition score (BCS) can lead to the deterioration of fertility results of Czech Fleckvieh cows. The BCS of cows was evaluated before calving and during the first five weeks of lactation. The evaluation was based on 338 Czech Fleckvieh cows calved between the October 13th, 2009 and April 27th, 2010 at one dairy farm. Analysis of relationships between the energy balance results and fertility score expressed by the reproduction results (pregnancy rate after the first and all inseminations, the insemination interval, service period, insemination index, calving period) of the observed group were performed. The higher body condition score of the Czech Fleckvieh cows before calving turned out advantageously regarding the energy source during the postpartal period. No negative effect of higher BCS in cows before calving was confirmed. The best reproduction parameters were attained in the group of cows with no change or marked increase of body condition after calving recorded. However, statistically significant differences between the groups were detected only in the third week of lactation. Significant differences in the level of body condition were detected in relation to the length and type of oestrus onset.

Description of nestbox visits and suckling events in a group housing system for rabbit does as compared to individual cages

Research was conducted to study nursing associated events of lactating rabbit does. Nest box visits and suckling events were investigated using 6 group pens (8 does/pen) and 12 enriched individual cages. Each group pen and individual cage was observed by video for one day per week until weaning at 35 d of lactation, with exception of the third week of lactation. In the first 2 wk of lactation, videotapes were analysed for the frequency and duration of nest box visits per day. The fourth and fifth week of lactation, suckling events on the floor of the group pens and nest box visits in the individual cages were analysed for one day per week. The first 2 wk of lactation, does visits to the nest boxes were less frequent (respectively 1.9±0.2 vs. 2.6±0.3, P&lt;0.1) and shorter (respectively 113±9 s vs. 158±15 s, P&lt; 0.05) in the group pens than in the individual cages. In the group pens, 32% of the does had intervals of &gt;24 h between nest box visits. In the cages, all does visited the nest boxes at least once a day. In the last 2 wk of lactation, in the group pens suckling duration (mean±standard deviation) was 89±49 and 92.2±37 s in respectively week 4 and 5. In 79% of the suckling events a mix of the does’ own and other kits were suckled. No difference was found in suckling duration between litters consisting of own and/or other kits. Thirty-two per cent of the does in week 4 and 62% of the does in week 5 did not suckle kits on the floor of the pen, whereas all the does in the cages still visited the nest boxes at least once every 24 h. Based on this study, it can be concluded that in group housing less frequent and shorter nest box visits as well as suckling events were found as compared to individual housing.

Fibre in late gestation gilt diets, glucose tolerance, and feed intake and bodyweight loss during subsequent lactation

Forty-nine crossbred gilts were fed one of three diets during the last month of their gestation: 2.5 kg of a standard diet (2.5C, n = 15), 3.5 kg of the same standard diet (3.5C, n = 17), or 3.5 kg of a high fibre diet, with 10.6% fibre compared with 4.4% fibre in the standard diet (3.5F, n = 17). The 3.5F and 3.5C gilts were fed at isocaloric and isonitrogenous levels. During the subsequent lactation, all gilts were fed the same lactation diet. Nineteen gilts (6 or 7 per treatment) were subjected to an oral glucose tolerance test around Day 110 of gestation. The high feed level (3.5C and 3.5F) resulted in a higher weight gain during gestation (P &lt; 0.05). Gilts fed the high fibre diet tended to have (P &lt; 0.10) piglets with a greater birthweight at farrowing (1535 g) than gilts fed the standard diet at 2.5 kg (1484 g). The 3.5C gilts (n.s.) and the 3.5F gilts (P &lt; 0.05) had a lower feed intake and more bodyweight loss during lactation than gilts fed the 2.5-kg standard diet during gestation. Insulin profiles after the glucose tolerance test were higher for gilts fed the high fibre diet. Gilts fed the 2.5- or 3.5-kg standard diet had a similar insulin profile. Glucose profiles and insulin sensitivity were similar across treatments. Leptin around Day 110 was negatively correlated with feed intake during the third week of lactation (r = –0.28; P &lt; 0.05). This study shows that a high feed level during late gestation reduces feed intake during lactation and that a high fibre diet during gestation does not negate this effect. The results suggest that feed level during gestation and the resulting body fat mass, rather than glucose tolerance, impacts on feed intake during lactation.

GENETIC AND NON-GENETIC FACTORS AFFECTING MILK PRODUCTION AND PREWEANING LITTER TRAITS OF NEW ZEALAND WHITE DOES UNDER EGYPTIAN CONDITIONS

Pour étudier les facteurs génétiques et non génétiques affectant la production laitière et les performances des portées avant sevrage, 519 portées de lapines Néo-­Zélandaises Blanches ont été utilisées. Le père de la portée affecte sigificativement (P&lt;0.05) la production laitière de la seule première semaine, tandis que la mère affecte significativement (P&lt;0.01) la production laitière de la majorité des autres semames expérimentales exceptée la quatrième semaine qui n'est pas affectée significativement. La production laitière la plus forte est obtenue pour la deuxième portée. La saison de mise bas affecte significativement (P&lt;0.01) la production laitière de la plupart des semaines etudiées, à l'exception de la 4ème semaine, dont la production est la plus faible en été, mais l'écart n'est pas significatif. La taille de la portée a la naissance affecte significativement (P&lt;0.01) la production laitière qui augmente en même temps que le nombre de jeunes nés. Le pic de la production laitière se situe en troisième semaine de lactation et atteint 155,3 g/jour. Le père affecte non significativement la plupart des performances d'avant sevrage étudiées, exceptée la taille de la portée a la naissance (P&lt;0.05). La mere affecte significativement la taille et le poids de la portée a la naissance et au sevra9e. La parité affecte significativement la taille de la portee et le po1ds au sevrage aussi bien que la mortalité avant sevrage. La saison de mise bas affecte non significativement la taille de la portée et le poids a la naissance, et significativement (P&lt;0.01) le poids au sevrage. La durée de la période "saillie fertile" a des effets hautement significatifs sur toutes les caractéristiques étudiées des portées avant sevrage. Les estimations d'héritabilité et de repétabilité concernant la production laitiere et les performances des portées, sont en général, faibles.

Fitness of four different mathematical models to the lactation curve of Brown Swiss cows in Konya Province of Turkey

The aim of this study was to investigate the fitness of Incomplete Gamma (WD), Exponential (WIL), Mixed Log (MIL) and Polynomial Regression (AS) models to the lactation curve of Brown Swiss Cows. Data were collected from 143 Brown Swiss cows raised on the Alt?nova State Farm in Konya Province, Turkey. Milk yield was recorded monthly, and milk records were started at the third week of lactation (mean = 16.9 day, SD = 0.7). Total milk yields estimated by the four models were very close to real total milk yield. The models were found to be adequate for estimation of milk yield. The MIL model underestimated the peak yield significantly. The differences between peak yields of the models and real peak yields were not significant and ranged from 27.70 to 29.01 L. All models forecasted peak time earlier than real peak time. The differences for the persistency values of the four models were significant. The AS model's persistency value was nearly equal to the real persistency value (77.56 vs. 77.59%). R2 values of the models changed from 86.05 to 97.95%. The AS model gave the best R2 and the least MSPE values. Consequently, the AS model showed the best fit to the lactation data of Brown Swiss cows and allowed a suitable definition of the lactation curve.Key words: Brown Swiss, cows, lactation curve, milk yield, mathematical model