Effect of gradual transition from maternal to reconstituted milk on behavioural,endocrine and immune responses of lambs

The possibility of reducing the stress associated with artificial rearing through a gradual transition from maternal to reconstituted milk was assessed in thirty Comisana lambs. Animals were assigned to a control dam-suckled group (Suckled) and two test groups. Eighteen to twenty-four hours after parturition, test lambs were separated from their dams: 10 subjects were offered a commercial milk substitute (Sub), whereas the other ten (Mix) were subjected to a gradual transition from maternal to reconstituted milk over ten days. Test-lambs had free access to milk 3 h a day. In vivo cell-mediated immune response of lambs to phytohemagglutinin percutaneous injection was evaluated at 5, 15 and 25 days of age. At 10 and 20 days of age, all lambs were subjected to 15 min isolation tests, during which latency time to move, duration of movement and number of bleats were recorded. Blood samples were collected immediately before the test, 15 and 60 min after in order to assess the effect of differential rearing on cortisol response of animals at different ages. In addition, weight gains of all lambs and milk intakes of test lambs were recorded during the first 35 days of age at weekly intervals. Sub showed a lower immune response (P<0.01) and, at 10 days of age, increased levels of plasma cortisol (P<0.001) as well as a reduced duration of movement (P<0.001) and a longer latency time to move (P<0.001) compared to Suckled and Mix. There were no significant differences between Suckled and Mix for both immune, cortisol and behavioural responses. Mix lambs consumed more milk (P<0.006) and had higher weight gains (P<0.001) compared to Sub lambs. However, Mix lambs gained less weight on average (P<0.05) than Suckled lambs. Our results suggest that a gradual transition from maternal to reconstituted milk is effective in stimulating milk consumption and minimising the detrimental effects of artificial rearing on behavioural, endocrine and immune responses of lambs.     

Wet brewers' grains or bean curd pomance as partial replacement of soybean meal for lactating cows

The purpose of this study was to evaluate the effects of supplementation of the by-product, brewers' grains and the bean curd pomance, on the performance of lactating cows and their ruminal characteristics. Through this, we wanted to increase resource utilization and to eliminate pollution from these by-products. Thirty-two Holstein lactating cows were allocated randomly into four dietary treatment groups. The experimental diets were formulated to be isoenergetic and isonitrogenous according to National Research Council (1989), and containing 35% corn silage, 20% alfalfa hay and 45% concentrates on DM basis. The dietary treatments consisted of the inclusion of different by-products sources. These included soybean bean (as the control), brewers' grains, bean curd pomance, and the mixed by-products (containing the same amount of brewers' grains and bean curd pomance). The experimental feeding lasted for eight weeks after one week of adaptation. In addition, four rumen cannulated Holstein cows were used in a 4×4 Latin square with 10-day period for collecting rumen samples. Results showed that cows that were fed the bean curd pomance diet produced significantly more milk than those that were fed the brewers' grains diet or the mixed by-product diet. The cows on the control diet produced significantly less milk than the other treatment groups (P<0.05). Both the control and brewers' grains groups consumed more feed than those in the bean curd pomance and mixed by-products diet groups (P<0.05). The cows that were fed the mixed by-products diet produced a significantly lower percentage of milk fat, total solids, milk protein and milk lactose than the others (P<0.05). The milk lactose percentage was significantly higher for cows that were fed the bean curd pomance than those fed the brewers' grains diet (P<0.05). Cows that were fed the bean curd pomance produced significantly more milk fat, total solids, milk protein and milk lactose than the others (P<0.05). Cows that were fed the mixed by-products diet produced significantly lower amount of milk fat, total solids and milk protein than the control and brewers' grains group (P<0.05). These diets did not significantly influence the body weight of the cows. It, however, significantly influenced the ruminal characteristics (P<0.05).     

Management practices associated with reproductive performance in Holstein cows on large commercial dairy farms

As a result of the increase in herd size and the intensification of production, the complexity of reproductive management has been growing in dairy herds. The aim of our study was to examine the associations of management practices and reproductive performance in Holstein cows on large commercial dairy farms. Management practices applied to cows were surveyed between 22 May and 6 November 2015 in 34 large Holstein-Friesian dairy herds in Hungary. Individual data of 23 784 cows that calved between 1 January 2014 and 31 December 2014 in the surveyed herds were gathered. Associations between the management practices and the reproductive parameters were analyzed by mixed effects models. Regarding heat abatement we found that ventilation with sprinklers was associated with the shortest breeding interval (P<0.01), the shortest calving to conception interval (P<0.01), and the highest odds of being pregnant by 200 days in milk (P<0.01). Solely ventilation showed similar (P>0.05) results to lack of heat stress protection. It was also revealed, that lack of a well-established voluntary waiting period (VWP) or a VWP shorter than 50 days was associated with less days to first service (P<0.01), shorter breeding interval (P<0.01) and calving to conception interval (P<0.05), as well as higher odds of carrying a calf by 200 days in milk (P<0.01) compared with those using a VWP of at least 50 days. Those farms that applied transrectal ultrasonography were more likely to use ventilation with sprinklers (P<0.05), hormonal synchronization (P<0.01) and to perform early pregnancy diagnosis followed by pregnancy recheck (P<0.05). The application of transrectal ultrasonography with one of the aforementioned practices was associated with reduced days to first service (P<0.05), shorter breeding interval (P<0.05) and higher odds of pregnancy at 200 days in milk (P<0.05). Our study highlights the management practices most closely related to improved reproductive performance, which are, therefore, suggested to be applied on dairy farms, considering the local circumstances of the individual farms.     

Meishan neonatal piglets tend to have higher intestinal barrier function than crossbred neonatal piglets

Meishan pigs tend to have higher disease resistance than commercial breeds, although more studies are needed to confirm this difference. This study compared intestinal barrier function between Meishan and crossbred neonatal piglets to provide guidance for both the breeding and nutritional regulation of pigs. Six Meishan piglets and 6 Duroc × (Landrace × Yorkshire) crossbred neonatal piglets (all with normal birth weights) were obtained and allocated into the MEIS and CROSS groups, respectively. Intestinal morphology, goblet cell numbers, antioxidant enzyme activity, and cytokine gene and tight junction protein expression were assessed. The results showed that BW was lower in the MEIS group than in the CROSS group (P < 0.01). The relative lengths of the duodenum (P < 0.05), jejunum (P < 0.01) and ileum (P < 0.01) in the MEIS group were higher than those in the CROSS group. Compared with the CROSS group, the MEIS group exhibited shorter villus lengths in the duodenum and jejunum (P < 0.01), a shallower crypt depth in the ileum (P < 0.001) and denser and longer microvilli in the intestine. The numbers of GCs in the duodenum (P < 0.01) and jejunum (P < 0.001) and the activity levels of glutathione peroxidase (P < 0.05) in the jejunum and of catalase (P < 0.01) and superoxide dismutase (P < 0.01) in the ileum were higher in the MEIS group than in the CROSS group. Compared with the CROSS group, the MEIS group exhibited higher gene expression levels of interleukin (IL) 4 and interferon γ (IFNγ) in the jejunum (P < 0.05); IL2 (P < 0.05), IL4 (P < 0.01) and IFNγ (P < 0.001) in the ileum; and mucin 2 (P < 0.01) and occludin (P < 0.05) in the duodenum. In conclusion, Meishan neonatal piglets showed lower birth weights but higher intestinal barrier function than crossbred piglets.     

Dam parity and calf sex affect maternal and neonatal behaviors during the first week postpartum in stabled Maghrebi dairy camels

Currently, a trend toward the commercialization of dromedary milk associated with recent intensive rearing systems has starting worldwide which impose constraints on animals affecting their behavioral repertoires and welfare status. The aim of this study was to investigate the effects of dam parity and calf sex on parturition, neonatal, and maternal behaviors in stabled Maghrebi dairy camels (Camelus dromedarius). Thirty-six (primiparas N = 10; multiparas N = 26) periparturient females were kept under video surveillance using a digital IR camera and 24-h sessions were chosen to assess calving, maternal, and neonatal behaviors in calving pens. Duration of restlessness, process of giving birth, and expulsion of fetal membranes were assessed. After first suckling, dams and their calves were moved into an individual enclosure to assess maternal behavior at 12 h, 24 h, 48 h, 72 h, and 7 d postpartum. Behavior was assessed using a camcorder for 30 min after 1 h of young separation in an adjacent enclosure. Results showed an effect of parity on the duration of the birth process which was longer for primiparous than multiparous camels (P = 0.034). During this stage, primiparous females tended to raise their tails more often (P = 0.054) and spent more time standing (P = 0.001) than multiparous camels. Neonatal behavior was affected by calf sex. Female newborns took less time to raise their heads (P = 0.041) and to stand up (P = 0.048) for the first time and were the earliest to suckle their dams (P = 0.032). Multiparous dams stood up sooner (P = 0.019) after calving and suckled their calves earlier (P = 0.043) than primiparous dams. They emitted more bleats and exhibited more sniffing during the first week postpartum than primiparas. During the first postpartum week, both primiparas and multiparas showed a decrease in the total number of bleats (P < 0.001), low-pitch bleats (P < 0.001), and high-pitch bleats (P < 0.001), in sniffing frequency (P < 0.001) and sniffing duration (P < 0.001). This is the first study to describe in detail the calving, maternal, and neonatal behaviors of dromedary camels and to show the influence of parity and calf sex. Maternal care toward the newborn calf exhibited by a high level of bleating and sniffing activities in the first 2 days suggest that they play an important role in the establishment of mother–young relationship.     

Overweight,hypertension and renal dysfunction in adulthood of neonatally overfed rats

Accelerated growth in early infancy has been associated with later cardiovascular and metabolic diseases. We investigated the influence of overnutrition during neonatal periods on the development of renal pathophysiological changes in adult offspring rats. Three or 10 male pups per mother were assigned to either the small litter (SL) or normal litter (NL) control groups during the first 21 days of life. The effects of early postnatal overnutrition on body weight, blood pressure and renal changes were determined at 3 and 6 months. Pups in the SL group weighed more than controls between 7 days and 6 months of age (P<.05). In the SL group, serum creatinine levels were higher at 3 and 6 months (P<.05), and at 6 months, blood pressure levels were higher than those of the controls (P<.05). The number of ED-1 positive macrophages in renal cortex and glomerulosclerosis index increased in the SL group at 3 and 6 months (P<.05). Additionally, cortical apoptotic cells increased in the SL group at 6 months (P<.05). Immunoblotting and immunohistochemistry showed that matrix metalloproteinase (MMP)-9 protein expressions decreased and tissue inhibitor of MMP-1, tumor necrosis factor-α, osteopontin and adiponectin expressions increased in the SL group at 3 months (P<.05). However, at 6 months, MMP-9 expression was elevated, and osteopontin expression remained elevated in the SL group (P<.05). Early postnatal overfeeding can lead to lasting overweight, hypertension and renal dysfunction and place a greater burden on the kidney.     

Effects of replacement of Moringa oleifera for berseem clover in the diets of Nubian goats on feed utilisation,and milk yield,composition and fatty acid profile

Replacement of conventional feedstuffs with cheap non-conventional ingredients may improve livestock performance and the quality of their products, particularly milk. The study considered the effects of Moringa oleifera (MO) foliage in replacement of berseem clover (BC) on feed utilisation and lactational performance in Nubian goats. A total of 16 lactating Nubian does, weighing 36.2±0.8 kg, were randomly assigned to four experimental treatments containing 0, 125, 250 and 375 g of MO per kg diet to replace 0 (M0), 25 (M25), 50 (M50) and 75% (M75) of BC (on dry matter (DM) basis) in a quadruplicated 4×4 Latin square design. The MO diets increased (P<0.01) feed intake and nutrient digestibility. Feeding MO diets improved (P<0.01) ruminal volatile fatty acids, acetate and propionate but reduced (P<0.01) valerate and iso-butyrate. Moringa diets increased (P<0.01) serum total protein, albumin and glucose but decreased (P<0.05) cholesterol and triglycerides. Milk yield and energy corrected milk, and milk total solids, fat and energy content were increased (P<0.01) in MO diets. Yields of milk components and energy were greater (P<0.05) for MO diets than for control diet. Milk total saturated fatty acids and athrogenicity index were lower (P<0.01), and unsaturated fatty acids, conjugated fatty acids and UFA/SFA ratio higher (P<0.05) for MO diets. It is concluded that feeding MO to replace 75% DM of BC improved feed utilisation, ruminal fermentation, and milk yield and quality in lactating Nubian goats.     

Biological mechanisms related to differences in residual feed intake in dairy cows

Residual feed intake (RFI), defined as the difference between an animal’s actual feed intake and expected feed intake over a specific period, is an inheritable character of feed conversion efficiency in dairy cows. Research has shown that a lower RFI could improve the profitability of milk production. This study explored variation in RFI by comparing the differences in body size, milk performance, feeding behavior, and serum metabolites in 29 Holstein cows in mid lactation. The cows were selected from a total of 84 animals based on their RFI following feedlot tests. Selected cows were ranked into high RFI (RFI >1 SD above the mean, n=14) and low RFI (RFI<1 SD below the mean, n=15). The low RFI cows (more efficient) consumed 1.59 kg/day less dry matter than the high RFI group (P<0.01), while they produced nearly equal 4% fat-corrected milk. The milk : feed ratio was higher for the low RFI group than for the high RFI group (P<0.05). The levels of milk protein (P<0.01), total solids (P<0.05), and nonfat solids (P<0.05) were also higher for the low RFI group, whereas milk urea nitrogen was lower (P<0.01). The daily feeding duration was shorter for the low RFI group than for the high RFI group (P<0.01). No significant differences were found in levels of glucose, β-hydroxybutyrate, prolactin, insulin, IGF-1, growth hormone or ghrelin, but the level of neuropeptide Y was higher (P<0.01) and levels of leptin and non-esterified fatty acid (P<0.05) were lower for the low RFI group than for the high RFI group. There were substantial differences between cows with different RFI, which might affect the efficiency of milk protein metabolism and fat mobilization.     

Taurine transporter gene expression in peripheral mononuclear blood cells of type 2 diabetic patients

Taurine acts as antioxidant, cell osmolyte, modulator of glucose metabolism, and plays a role in the retinal function. It is 10³-fold more concentrated in the intracellular than in the extracellular milieu due to a specific taurine-Na-dependent transporter (TauT), which is upregulated by hypertonicity, low extracellular taurine, or oxidative stress and acutely downregulated ‘in vitro’ by high glucose concentrations. Aim of this study was to investigate whether TauT expression was modified in mononuclear peripheral blood cells (MPC) of type 2 diabetic patients with or without micro/macrovascular complications. Plasma taurine, as well as other sulphur-containing aminoacids (assayed by HPLC) and TauT gene expression (assayed by real-time PCR analysis) were measured in MPC of 45 controls and of 81 age-and-sex matched type 2 diabetic patients with or without micro/macrovascular complications. Median value (interquartile range) of plasma taurine was significantly lower in diabetic patients than in controls [28.7 (13.7) μmol/l vs. 46.5 (20.3) μmol/l; P?<?0.05], while median TauT expression, in arbitrary units, was significantly higher in diabetics than in controls [3.8 (3.9) vs. 1 (1.3); P?<?0.05) and was related to HbA1c only in controls (r?=?0.34; P?<?0.05). Patients with retinopathy (n?=?25) had lower TauT expression than those who were unaffected [3.1 (2.8) vs. 4.1 (3.4); P?<?0.05], while persistent micro/macroalbuminuria was associated with unchanged TauT expression. A trend toward reduction in TauT expression was observed in patients with macroangiopathy [n?=?27; 3.3 (2.5) vs. 4 [3.7]; P?=?NS]. In conclusion, TauT gene is overexpressed in MPC of type 2 diabetic patients, while presence of retinopathy is specifically associated with a drop in TauT overexpression, suggesting its possible involvement in this microangiopathic lesion.     

Effect of glycerol supplementation during early lactation on milk yield,milk composition,nutrient digestibility and blood metabolites of dairy buffaloes

This study was conducted to evaluate the effect of increasing levels of glycerol in the diet on milk yield and composition, diet digestibility and some blood metabolites of dairy buffaloes in early lactation. A total of 24 buffaloes were blocked by average milk yield, parity and BW and then randomly assigned to three treatments: control without glycerol (CON); low glycerol (LG): control plus glycerol at 150 ml/day per buffalo; and high glycerol (HG): control plus glycerol at 300 ml/day per buffalo. The experimental period lasted for 60 days. Feeding LG and HG decreased (P<0.0001) dry matter intake compared with the CON. Buffaloes supplemented with LG and HG produced more milk (P<0.01) and had a greater (P<0.0001) yield of fat-corrected milk (3.5%) than those buffaloes fed control treatment. Glycerol-supplemented buffaloes showed a positive energy status indicated by reduced concentrations of non-esterified fatty acids and β-hydroxybutyrate. Feeding LG and HG tended to increase (P⩽0.10) concentrations of milk fat, and serum total protein and globulin and significantly decreased (P⩽0.05) milk urea nitrogen and somatic cells counts (SCCs) compared to the CON group. Inclusion of LG and HG had no effect on organic matter and non-fiber carbohydrate digestion, but improved dry matter (P=0.02), CP (P=0.09), ether extract (P=0.03), NDF (P=0.07) and ADF (P=0.03) digestion.     

Evaluation of Selenium,Redox Status and Their Association with Plasma Amyloid/Tau in Alzheimer’s Disease

The aim of the study was to evaluate blood selenium and antioxidants as possible oxidative stress markers in Alzheimer’s disease (AD) along with amyloid β42 (Aβ42) and tau by comparing them with vascular dementia (VD) and age-matched healthy controls. Selenium, total tau, Aβ42, glutathione (GSH) and malondialdehyde (MDA) levels and the activities of antioxidant enzymes were analysed in the blood of AD patients (n?=?30), VD patients (n?=?35) and controls (n?=?40) from South India. Plasma Aβ42 level was significantly higher (P?<?0.001) in both AD and VD compared to controls. Total tau and tau-to-amyloid ratio were significantly lower in both AD and VD (P?<?0.001), compared to controls, and a significant difference (P?<?0.01 and P?<?0.05, respectively) was also observed between AD and VD. The receiver operating characteristic (ROC) curve-derived cutoff values of <3.5 for tau-to-Aβ42 ratio and <520 pg/ml for total tau showed sensitivity and specificity of around 67–72 % for differentiating AD from VD and around 90 % for AD from controls, indicating that they could serve as reliable AD-specific markers. The MDA levels were significantly higher (P?<?0.001) in both dementia groups along with a significant decrease (P?<?0.001) in reduced GSH levels, indicating elevated oxidative stress and altered redox status in both forms of dementia. Selenium levels did not vary significantly between the three groups. The activity of glutathione peroxidase increased in both AD and VD compared to controls, with a concomitant decrease in glutathione reductase and glucose-6-phospate dehydrogenase (P?<?0.001) activity. The activity of thioredoxin reductase was significantly lower in both patient groups (P?<?0.001) compared to healthy controls. No correlation was observed between selenium and activities of selenoenzymes, tau, Aβ42 or tau-to-Aβ42 ratio, when analysing independently, indicating that blood selenium may not be directly involved in Aβ production and in regulating tau/Aβ42-mediated mechanism in AD. The present study emphasizes the enhanced oxidative stress in AD pathology and plasma tau and tau-to-amyloid ratio as possible markers to differentiate AD from VD. The study also points that blood selenium may not be involved in regulating oxidative stress in AD, and a longitudinal study correlating plasma and cerebrospinal fluid (CSF) selenium and selenoprotein levels is warranted.     

Effect of litter size,milk replacer and housing on production results of hyper-prolific sows

The modern hyper-prolific sow gives birth to more piglets than she has functional teats (in the following called supernumerary piglets). The aim of the present study was (1) to investigate the production consequences of hyper-prolific sows rearing supernumerary piglets equal to the mean live-born litter size, and (2) investigate whether potential negative effects on survival and growth could be alleviated by providing access to milk replacer and/or providing easier access to the udder (by loose housing). At day 1 (D1) postpartum (pp), 93 litters were standardised to 14 or 17 piglets (LS14/LS17) after which no piglets were moved between sows leading to decreased litter size if piglets died. Litters were provided with or without milk replacer in milk cups (+MILK/−MILK), and sows were either crated or loose housed (CRATE/LOOSE) in a 2 × 2 × 2 factorial design. Piglet mortality was higher in LS17 compared to LS14 (P < 0.01; OR = 2.0), higher in −MILK compared to +MILK (P = 0.01; OR = 1.2) and higher in LOOSE compared to CRATE (P = 0.02; OR = 1.8). This study showed that sow rearing of supernumerary piglets while supplying with milk replacer can increase piglet survival. It also showed that early mortality before piglets learned to drink milk replacer posed a challenge using this automatic milk replacer system. An interaction between access to milk replacer and the standardised litter size D1 affected litter weight (P < 0.01) and piglet weight day 28 (D28) (P = 0.03). The highest litter weight D28 was found in LS17 +MILK (P < 0.01) but with a lower individual piglet weight than in LS14 −MILK. Piglet weight D28 was higher in LS14 −MILK compared to LS17 regardless of access to milk replacer. Heterogeneity in piglet weight within litters D28 was larger in LS17 (P = 0.03) but could be reduced with +MILK in CRATE (P < 0.01). No effects were found on sow weight loss and feed intake (P > 0.05). In conclusion, the results showed that sows cannot rear the supernumerary piglets without further management interventions to reduce mortality. Supplying supernumerary piglets equal to the mean live-born litter size of hyper-prolific sows with milk replacer can from results of this study be an alternative strategy to the use of nurse sows.     

Promoter variants at AP2 box region of Hsp70.1 affect thermal stress response and milk production traits in Frieswal cross bred cattle

Heat shock proteins (Hsp) are known to play major role in protection of cells from thermal stress. Nucleotide polymorphisms within the promoter of Hsp affect degree of expression and inducibility of Hsp mRNA. The present study aimed to investigate the effect of polymorphism within promoter region on the cellular expression of Hsp70.1 mRNA and association of identified polymorphisms with the physiological parameters during summer stress and milk production traits in dairy cattle. Two hundred Frieswal cows were genotyped using double PCR-RFLP to identify deletion of cytosine within the Hsp70.1 promoter AP2 box at base position 895. Homozygous wild type genotypes (CC) were found in lower frequency (39.29, n = 78) than heterozygous cytosine deletion mutant genotypes (C −) (60.71, n = 122). In the observed physiological parameters (rectal temperature, respiration rate and heat tolerance coefficient), cows that were homozygous wild types had better significant (P < 0.05) summer tolerance than the heterozygous deletion genotypes. Cytosine deletion mutation in the promoter region negatively affected (P < 0.01) the expression of Hsp70.1 mRNA in peripheral bovine mononuclear cells (PBMC) subjected to in vitro heat stress. Further association of observed polymorphism with the milk production traits was significant as the heterozygous cytosine deletion cows had lower total milk yield, peak yield, yield at 300 days, protein% (P < 0.01) and fat% (P < 0.05) than the native wild type promoter cows. The results from the present study suggest that the promoter region of bovine hsp70.1 gene is polymorphic and may be useful in selection of dairy cows for relatively better thermotolerance and higher milk production.     

Association of genetic polymorphism inGH gene with milk production traits in Beijing Holstein cows

Associations were analysed between polymorphisms of the growth hormone gene (GH-MspI) (localized in intron 3) and milk production traits of Beijing Holstein cows (a total of 543 cows). Polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method was used for identification of various geno-types. Frequencies of genotypes were 0.77, 0,21 and 0.02 for A/A, A/B and B/B, respectively. The frequency of theGH ^A allele is 0.875. The results of the least squares means show that in all three lactations, theGH A/A cows yielded more milk (P < 0.01 for lactation I andP 0.05 for lactations II and III), whereas A/B cows showed higher milk fat content than A/A individuals (P < 0.05 for lactations I and II, andP < 0.01 for lactation III). The A/A cows yielded more fat than A/B individuals (P < 0.01 only in lactation I). The A/A cows yielded more milk protein than A/B individuals (P < 0.01 for lactations I, II, and III). The A/A cows produced milk of higher protein content than of A/B individuals (P < 0.05 only in lactation II).     

Effect of lysophospholipids in diets differing in fat contents on growth performance,nutrient digestibility,milk composition and litter performance of lactating sows

It is well known that energy plays an important role in sow growth and development. Increasing the utilization of lipids will be beneficial to sows. Emulsifiers are substances which stabilize mixtures and prevent oil and water from separating, thereby enhancing the digestion of lipids. This study was conducted to evaluate the effect of dietary emulsifier (lysophospholipids (LPL)) supplementation in diets differing in fat contents on growth performance, nutrient digestibility and milk composition in lactating sows, as well as performance and fecal score in piglets. A total of 32 multiparous sows (Landrace×Yorkshire) were used in a 21-day experiment. On day 110 of gestation, sows were weighed and moved into the farrowing facility, randomly assigned in a 2×2 factorial arrangement according to their BW with two levels of LPL (0 and 30 mg/kg) and two levels of fat (4.75% and 2.38% fat; 13.66 and 13.24 MJ/kg). BW loss and backfat thickness loss were decreased (P<0.05) by LPL supplementation. Backfat thickness at weaning was higher (P<0.05) in sows fed LPL supplementation diets. The apparent total tract digestibility of dry matter, nitrogen, gross energy and crude fat in sows fed LPL diets was increased (P<0.05) compared with those fed non-LPL diets. Sows fed the high-fat diets had higher (P<0.05) milk fat on day 10 and milk lactose on day 20 than those fed the low-fat diets. Milk fat and lactose concentrations in LPL supplementation treatments was increased (P<0.05) compared with non-LPL treatments on day 10 and day 20, respectively. Positive interaction effects (P<0.05) between fat and LPL were observed for milk fat concentration on day 10. In conclusion, LPL addition decreased BW loss and backfat thickness loss, improved nutrient digestibility and milk fat as well as milk lactose concentrations. In addition, there was a complementary positive effect of dietary fat and LPL supplementation on milk fat concentration in lactating sows.     

Evaluation of production efficiencies at pasture of lactating suckler cows of diverse genetic merit and replacement strategy

Feed costs account for the largest proportion of direct cost within suckler beef production systems. By identifying the cow type with enhanced capability of converting grazed herbage to beef output across lactations, suckler cow systems would become more efficient and sustainable. The objective of this study was to estimate grass DM intake (GDMI) and production efficiency among lactating suckler cows of diverse genetic merit for the national Irish maternal index (Replacement Index) which includes cow efficiency components such as milk yield and feed intake. Data from 131 cows of diverse genetic merit within the Replacement Index, across two different replacement strategies (suckler or dairy sourced), were available over two grazing seasons. Milk yield, GDMI, cow live weight (BW) and body condition score (BCS) were recorded during early, mid and late-lactation, with subsequent measures of production efficiency extrapolated. Genetic merit had no significant effect on any variables investigated, with the exception of low genetic merit (LOW) cows being 22 kg heavier in BW than high genetic merit (HIGH) cows (P < 0.05). Beef cows were 55 kg heavier in BW (P < 0.001), had a 0.31 greater BCS (P < 0.05) and 0.30 Unité Fourragère Lait (UFL) greater energy requirement for maintenance compared to dairy sourced beef × dairy crossbred (BDX) cows (P < 0.001). The BDX had 0.8 kg greater GDMI, produced 1.8 kg more milk (P < 0.001), had a 0.8 UFL greater energy requirement for lactation and produced weanlings that were 17 kg heavier in BW than beef cows (P < 0.05). Subsequent efficiency variables of milk per 100 kg BW (P < 0.001), milk per kg GDMI (P < 0.001) and GDMI per 100 kg BW (P < 0.001) were more favourable for BDX. The correlations examined showed GDMI had moderate positive correlations (P < 0.001) with intake per 100 kg BW, net energy intake per kg milk yield, RFI and intake per 100 kg calf weaning weight but was weakly negatively correlated to milk yield per kg GDMI (P < 0.001). No difference was observed across genetic merit for beef cows for any of the traits investigated. Results from the current study showed that, while contrasting replacement strategies had an effect on GDMI and production efficiency, no main effect was observed on cows diverse in genetic merit for Replacement Index. Nonetheless, utilising genetic indexes in the suckler herd is an important resource for selecting breeding females for the national herd and phenotypic performance generated from this study can be included in future genetic evaluations to improve reliability of genetic values.     

Effects of dry period length on milk production and energy balance in two cow breeds

Shortening the dry period (DP) has been proposed as a strategy to improve energy balance (EB) in cows in early lactation. This study evaluated the effects of shortening the DP on milk yield (MY), EB and residual feed intake (RFI) in two breeds; Swedish Red (SR) and Swedish Holstein (SH). Cows were blocked by breed and parity and then randomly assigned to one of two treatments; short DP of 4 weeks (4W, n=43) or conventional DP of 8 weeks (8W, n=34). Cows were kept and fed under the same conditions, except for the 4 weeks when the 4W group were still lactating prepartum and thus kept with the lactating cows. Milk yield and BW were recorded and body condition score (BCS) was rated from 10 weeks prepartum to 12 weeks postpartum. Dry matter intake (DMI) was recorded for lactating cows postpartum. Milk yield was reduced by 6.75 kg/day during the first 12 weeks postpartum (P<0.001) for the 4W cows compared with 8W cows, but there was no significant difference in total MY (3724 kg compared with 3684 kg, P=0.7) when the milk produced prepartum was included. Protein content was higher in 4W cows (3.42%) than in 8W cows (3.27%) (P<0.001) postpartum. In the 8W group, cows lost more BCS after calving (P<0.05). Cows of SR breed had higher BCS than cows of SH breed (SR=3.7, SH=3.2, P<0.001), but no differences in BW were found between breed and treatment. Energy balance was improved for cows in the 4W group (P<0.001), while feed efficiency, expressed as RFI, was reduced for 4W cows than for 8W cows (5.91 compared with −5.39, P<0.01). Shortening the DP resulted in improved EB postpartum with no difference between the breeds and no milk losses when including the milk produced prepartum.     

Ability of dairy cows to be inseminated according to breed and genetic merit for production traits under contrasting pasture-based feeding systems

Strong genetic selection on production traits is considered to be responsible for the declined ability of dairy cows to ensure reproduction. The present study aimed to quantify the effect of genetic characteristics (breeds and genetic merit for production traits) and feeding systems (FS) on the ability of dairy cows to be inseminated. An experiment was conducted during 9 years on Normande and Holstein cows assigned to contrasted pasture-based FS. Diets were based on maize silage in winter and grazing plus concentrate in spring in the High FS; and on grass silage in winter and grazing with no concentrate during spring in the low FS. Within breed, cows were classified into two genetic groups with similar estimated breeding values (EBV) for milk solids: cows with high EBV for milk yield were included in a Milk-Group and those with high EBV for fat and protein contents were included in a Content-Group. Holstein produced more milk throughout lactation than Normande cows (+2294 kg in the High FS and +1280 kg in the Low FS, P<0.001) and lost more body condition to nadir (−1.00 point in the High FS and −0.80 kg in the Low FS, P<0.001). They also showed a poorer ability to be inseminated because of both a delayed commencement of luteal activity (CLA) and delayed first service (more days from start of the breeding season to first service, DAI1). Cows in the Milk-Group produced more milk than cows in the Content-Group, but milk solids production was similar. Cows in the Content-Group had earlier CLA than cows in the Milk-Group (P<0.01). Genetic group neither affected ovulation detection rate nor DAI1. Within breed and FS, cows with high genetic merit for milk yield had later CLA and DAI1. Cows in the High FS produced more milk and lost less condition to nadir than cows in the Low FS. FS did not affect dairy cows’ ability to be inseminated. However, cows with higher milk protein content, and presumably better energy balance, had earlier CLA (P<0.01) and DAI1 (P<0.10). In addition, higher milk yield was associated with poorer ovulation detection rate and oestrus intensity (P<0.05). The study showed that at similar EBV level for milk solids, selection for increased milk fat and protein content resulted in improved cyclicity and similar oestrous expression and submission rates compared with selection for increased milk yield.