Milk production of cows grazing pasture supplemented with grain mixes containing canola meal or corn grain or both over the first 100 days of lactation.

Grain mixes varying in proportions of wheat grain, barley grain, canola meal, and corn grain were fed to grazing dairy cows in early lactation to determine the contribution of canola meal and corn grain to milk yield, BW, BCS, eating behavior, and blood serum metabolite concentrations. The experiment used 80 multiparous, seasonally calving Holstein-Friesian dairy cows during the first 100 d of lactation, the treatment period, and over the subsequent carryover period of 100 d, during which all cows were fed a common diet. Cows were divided into 4 cohorts (blocks) based on calving date and within each cohort, 5 cows were randomly allocated to each of the 4 treatments. Dietary treatments included disc-milled grain mixes comprising (on a DM basis) (1) a control treatment of wheat (25%) and barley (75%); (2) wheat (25%), barley (50%), and canola meal (25%); (3) wheat (25%), barley (50%), and corn (25%), and (4) wheat (25%), barley (25%), canola meal (25%), and corn (25%). Treatment diets were introduced at 19 DIM ± 4.7 d, which included a 7-d adaptation period and were applied up until 100 DIM. Each grain mix was fed at 9 kg of DM/cow per day, offered twice daily, in equal proportions in the parlor at milking times. In addition to the grain mix, all cows grazed perennial ryegrass pasture at a daily allowance of ∼35 kg of DM/cow per day (measured to ground level). Results were analyzed in terms of corn and canola presence or absence in the diet. Including canola meal in grain mixes increased grain intake and pasture intake by 0.6 and 2.1 kg of DM/cow per day, respectively, resulting in an increased milk yield of 2.6 kg/cow per day during the first 100 d of lactation. Including canola meal also increased yields of milk fat and protein, and concentrations of milk fat, as well as increasing mean BW and BCS over the 100 d. The inclusion of canola meal in the grain mixes also resulted in greater blood serum BHB and urea concentrations, compared with feeding grain mixes that did not contain canola meal. The inclusion of corn grain provided no milk production benefits and did not change BW, BCS, or any feeding behavior variables. There were no carryover effects on milk production from either canola meal or corn grain after the treatment period. In summary, the results demonstrate that the provision of canola meal in grain mixes can improve milk production and increase mean BCS. Further, there are no benefits to milk yield when a proportion of barley is substituted for corn, in a wheat and barley grain mix fed to grazing dairy cows in early lactation. However, these results are dependent on the level of inclusion and the feeding system employed.

Effect of forage type on swallowed bolus mass and a method for counting swallows in dairy cattle.

Dry matter intake (DMI) is a primary determinant of milk production in grazing dairy cows and an ability to measure the DMI of individual cows would allow herd managers to formulate supplementary rations that consider the amount of nutrients ingested from grass. The 2 related aims of this experiment were to define the mean number of swallowed boli and mass of the swallowed boli in Holstein-Friesian dairy cattle offered a variety of forages commonly fed in the dairy industry of southeastern Australia, and to evaluate 2 indirect methods for counting the number of swallows. Twelve ruminally-fistulated, lactating Holstein-Friesian cows were randomly assigned to 3 replicated 4 × 4 Latin square designs and offered 4 forages: fresh chicory (FC), fresh perennial ryegrass (RP), alfalfa hay (AH), and perennial ryegrass silage (RS). The experiment was conducted over 28 d with each of 4 periods consisting of 7 d with 3 d of measurement. Forage diets were offered to individual cows following the partial evacuation of the rumen. The first 20 min after forage was offered constituted the measurement period, during which all swallowed boli were manually captured by samplers who placed their hand through the ruminal fistula and over the cardia entrance of the rumen of each cow. Concurrently, microphones and video cameras were used for the indirect measurement of swallows. The average swallowed bolus mass overall was 17.4 g dry matter (DM) per bolus with the lowest mass observed in cows offered FC (8.9 g DM/bolus), followed by RP (14.9 g DM/bolus), compared with cows offered AH (23.6 g DM/bolus) and RS (22.3 g DM/bolus). The swallowing rate was greater in cows offered FC (78 swallows/20 min) than in cows offered RP, AH, and RS (62.3 swallows/20 min). The audio recording method showed greater concordance (Lin's concordance correlation coefficient = 0.90) with the physical capturing of the boli through the rumen, than the video recording method did (Lin's concordance correlation coefficient = 0.54). It is concluded that the mass of the swallowed boli is related to forage type and that using a microphone attached to the cow's forehead can provide an accurate measure of the number of swallows when verified against the actual number of swallows counted by manual interception of the boli at the rumen cardia.

Using estimated nutrient intake from pasture to formulate supplementary concentrate mixes for grazing dairy cows.

In pasture-based dairy systems, feeding a complex concentrate mix in the parlor during milking that contains cereal grains and protein supplements has been shown to have milk production advantages over feeding straight cereal grain. This experiment had the aim of testing whether further milk production advantages could be elicited by adjusting the composition of the concentrate mix in an attempt to match the expected nutrient intake from pasture during late spring. The experiment used 96 lactating dairy cows, grazing perennial ryegrass pasture offered at a target allowance of 30 kg of dry matter/cow per day (to ground level) during late spring (mid October to November) in southeastern Australia. Cows were allocated into 3 replicates of 4 treatment groups, with 24 cows in each treatment. Each treatment group was offered 1 of 4 dietary treatments in the parlor at milking: control consisting of crushed wheat and barley grains; formulated grain mix (FGM) consisting of crushed wheat, barley, and corn grains and canola meal; designer grain mix 1 (DGM1) consisting of the same ingredients as the FGM grain mix but formulated using the CPM Dairy nutrition model to take into account the expected nutrient intake from pasture; and designer grain mix 2 (DGM2) consisting of the same ingredients as DGM1 but with canola meal replaced by urea and a fat supplement (Megalac, Volac Wilmar, Gresik, Indonesia). Concentrate mixes were offered at 8.0 kg of dry matter/cow per day, except for DGM2 cows, which were offered 7.5 kg of dry matter/cow per day. The experiment ran for a total of 28 d; after a 14-d adaptation period, nutrient intake, milk production, and body weight were measured over a 14-d measurement period. Milk yield (kg) of cows fed the FGM diet was greater than that of the control cows but was not different from that of the DGM1 and DGM2 cows. However, milk fat and protein yields (kg) were greater for cows fed the FGM diet than for all other diets. There was no difference in estimated daily pasture or total dry matter intakes between the 4 treatment groups, despite cows fed the DGM2 treatment consuming less of the concentrate mix (average 6.5 kg of dry matter/cow per day when offered 7.5 kg of dry matter/cow per day). This research has demonstrated the potential for using a nutrition model to take into account the expected nutrient intake from pasture to formulate a concentrate mix (DGM1) to achieve similar milk yields, but also highlighted the need for near real-time analyses of the pasture to be grazed so as to also capture benefits in terms of milk fat and protein yield.

Associations between milk protein concentration at various stages of lactation and reproductive performance in dairy cows.

Milk protein concentration has been positively associated with a range of measures of reproductive performance in dairy cows. These beneficial associations are most likely due to factors affecting both milk protein concentration and reproductive performance possibly being mediated, in part, by energy balance during early lactation. However, it is likely that factors other than energy balance are also involved in these relationships. A retrospective single cohort study was conducted using subsets of data collected from 74 dairy herds with seasonal or split calving patterns. Associations between milk protein concentration at various stages of lactation and reproductive performance in Holstein dairy cows were assessed using random effects logistic regression and survival analysis with milk protein concentration during the cow's breeding period fitted as a time-varying covariate. The beneficial associations between milk protein concentration and each of the 4 selected indices for measuring reproductive performance were evident when milk protein concentration was derived for each 30-d period from calving up to 300d in milk. For the first 150d of lactation the adjusted odds ratios were highest from 31 to 60d and only slightly lower for all periods up to 150d of lactation. Estimated associations for 31 to 60d were stronger than for 0 to 30d. In addition, milk protein concentration during a cow's breeding period was positively associated with the subsequent daily hazard of conception, even after adjusting for milk protein concentration in the cow's first or second month of lactation. Milk protein concentrations from 0 to 30d of lactation were less closely correlated with concentrations measured at subsequent 30-d intervals; correlations were closer between other periods in lactation. These results indicate that the association between milk protein concentration and reproductive performance is partly due to factors other than the extent of negative energy balance in early lactation. However, it is possible that energy balance accounts for some of the relationship as the magnitude and direction of energy balance can vary within and between cows throughout lactation. Factors determining milk protein concentration during the first 30d of lactation are not identical to the causes of milk protein concentration later in lactation, and some of the latter causes of milk protein concentration may be more closely related to the underlying mechanisms contributing to the milk protein concentration-reproductive performance relationship. Milk protein concentrations from a single test day from any day of lactation predict subpopulations of cows with differing average reproductive performance; milk protein concentrations measured after 30d of lactation are more useful than concentrations measured in the first 30d for identifying these subpopulations. Further research is required to identify the causes of these associations.

Associations between milk protein concentration, milk yield, and reproductive performance in dairy cows.

Milk protein concentration in dairy cows has been positively associated with a range of measures of reproductive performance. It was possible that these associations were due to confounding by milk volume. A retrospective single cohort study was conducted using data collected from 74 dairy herds with seasonal or split calving patterns. Associations between milk protein concentration and reproductive performance in Holstein dairy cows were assessed using random effects logistic regression. The key finding from this study was that the associations between milk protein concentration in early lactation and reproductive performance were not due to confounding by milk yield. Associations between milk protein concentration and reproductive performance were weaker at higher early lactation milk yields, but positive associations were evident at all milk volumes assessed. The second major finding was that increases in milk yield were associated with improved proportions of cows pregnant by wk 6 and 21 at low to moderate milk protein concentrations but with decreases in these reproductive measures at high milk protein concentrations. Thus, no simple relationship is present between milk yield and reproductive performance; effects of milk yield depend on milk protein concentration. These results indicate that mechanisms causing the associations between milk protein concentration and reproductive performance may be linked to milk yield but these mechanisms operate over a wide range of milk yields (<2,000 to ≥5,000kg in the first 120d of lactation). Further research is required to identify the causes of these associations.

Associations of high and low milk protein concentrations with energy allocation, milk production, and concentrations of blood plasma metabolites and hormones in Holstein-Friesian cows.

A positive association between milk protein concentration (MPC) and reproductive performance in dairy cows has been shown in several studies globally. This association may positively influence farm productivity and profitability, particularly in seasonally calving, pasture-based herds. However, the differences in milk production and energy allocation, physical characteristics, and blood plasma nutrient status between cows with differing MPC have not been examined, and the underlying mechanisms responsible for the association remain undefined. The objective of this study was to examine associations between MPC and nutrient partitioning in primiparous Holstein-Friesian cows managed under pasture-based dairying conditions, and to identify differences that may indicate the underlying mechanisms. Data were collected from 85 cows at regular intervals during the early part of the 2013 to 2014 seasonal lactation, including daily milk yield, weekly milk composition, weekly body condition score measurements, as well as weekly blood plasma metabolite and hormone concentrations. Cows were retrospectively separated into quartiles based on their average MPC during the first 120d of lactation, and comparisons were made between cows within the highest (high; 3.22 to 3.40%) and the lowest (low; 2.87 to 3.00%) MPC quartiles. The high-MPC cows had lower daily milk yields, yet did not differ in the daily yields of milk solids (protein + fat) compared with the low-MPC cows. After parturition, the high-MPC cows had greater blood plasma concentrations of glucose, insulin, insulin-like growth factor-1 and leptin compared with the low-MPC cows and maintained their body condition score, despite no differences in these variables prepartum. These results indicate an increased partitioning of nutrients toward milk synthesis at the expense of body condition for cows in the low MPC quartile. However, average daily energy outputs in milk were similar in the high- and low-MPC cows. The high-MPC cows calved 12d earlier in the seasonal calving period, reflecting superior reproductive performance when cows in this quartile were 15mo of age. These results suggest that at least part, but not all, of the reported associations between MPC and dairy cow fertility are related to nutrient status during early lactation. Further research is required to understand and use the association.

Testisin, a new human serine proteinase expressed by premeiotic testicular germ cells and lost in testicular germ cell tumors.

We have cloned and characterized a cDNA encoding a new human serine proteinase, testisin, that is abundantly expressed only in the testis and is lost in testicular tumors. The testisin cDNA was identified by homology cloning using degenerate primers directed at conserved sequence motifs within the catalytic regions of serine proteinases. It is 1073 nucleotides long, including 942 nucleotides of open reading frame and a 113-nucleotide 3' untranslated sequence. Northern and dot blot analyses of RNA from a range of normal human tissues revealed a 1.4-kb mRNA species that was present only in testis, which was not detected in eight of eight testicular tumors. Testisin cDNA is predicted to encode a protein of 314 amino acids, which consists of a 19-amino acid (aa) signal peptide, a 22-aa proregion, and a 273-aa catalytic domain, including a unique 17-aa COOH-terminal hydrophobic extension that is predicted to function as a membrane anchor. The deduced amino acid sequence of testisin shows 44% identity to prostasin and contains features that are typical of serine proteinases with trypsin-like substrate specificity. Antipeptide antibodies directed against the testisin polypeptide detected an immunoreactive testisin protein of Mr 35,000-39,000 in cell lysates from COS-7 cells that were transiently transfected with testisin cDNA. Immunostaining of normal testicular tissue showed that testisin was expressed in the cytoplasm and on the plasma membrane of premeiotic germ cells. No staining was detected in eight of eight germ cell-derived testicular tumors. In addition, the testisin gene was localized by fluorescence in situ hybridization to the short arm of human chromosome 16 (16p13.3), a region that has been associated with allellic imbalance and loss of heterozygosity in sporadic testicular tumors. These findings demonstrate a new cell surface serine proteinase, loss of which may have a direct or indirect role in the progression of testicular tumors of germ cell origin.

Genomic Selection Improves Heat Tolerance in Dairy Cattle.

Dairy products are a key source of valuable proteins and fats for many millions of people worldwide. Dairy cattle are highly susceptible to heat-stress induced decline in milk production, and as the frequency and duration of heat-stress events increases, the long term security of nutrition from dairy products is threatened. Identification of dairy cattle more tolerant of heat stress conditions would be an important progression towards breeding better adapted dairy herds to future climates. Breeding for heat tolerance could be accelerated with genomic selection, using genome wide DNA markers that predict tolerance to heat stress. Here we demonstrate the value of genomic predictions for heat tolerance in cohorts of Holstein cows predicted to be heat tolerant and heat susceptible using controlled-climate chambers simulating a moderate heatwave event. Not only was the heat challenge stimulated decline in milk production less in cows genomically predicted to be heat-tolerant, physiological indicators such as rectal and intra-vaginal temperatures had reduced increases over the 4 day heat challenge. This demonstrates that genomic selection for heat tolerance in dairy cattle is a step towards securing a valuable source of nutrition and improving animal welfare facing a future with predicted increases in heat stress events.

Hypermethylation of the 5' CpG island of the gene encoding the serine protease Testisin promotes its loss in testicular tumorigenesis.

The Testisin gene (PRSS21) encodes a glycosylphosphatidylinositol (GPI)-linked serine protease that exhibits testis tissue-specific expression. Loss of Testisin has been implicated in testicular tumorigenesis, but its role in testis biology and tumorigenesis is not known. Here we have investigated the role of CpG methylation in Testisin gene inactivation and tested the hypothesis that Testisin may act as a tumour suppressor for testicular tumorigenesis. Using sequence analysis of bisulphite-treated genomic DNA, we find a strong relationship between hypermethylation of a 385 bp 5' CpG rich island of the Testisin gene, and silencing of the Testisin gene in a range of human tumour cell lines and in 100% (eight/eight) of testicular germ cell tumours. We show that treatment of Testisin-negative cell lines with demethylating agents and/or a histone deacetylase inhibitor results in reactivation of Testisin gene expression, implicating hypermethylation in Testisin gene silencing. Stable expression of Testisin in the Testisin-negative Tera-2 testicular cancer line suppressed tumorigenicity as revealed by inhibition of both anchorage-dependent cell growth and tumour formation in an SCID mouse model of testicular tumorigenesis. Together, these data show that loss of Testisin is caused, at least in part, by DNA hypermethylation and histone deacetylation, and suggest a tumour suppressor role for Testisin in testicular tumorigenesis.

Renal cell carcinoma may adapt to and overcome anti-angiogenic intervention with thalidomide.

OBJECTIVE: To report on the failure of thalidomide to inhibit tumour growth in an animal model of human renal cell carcinoma (RCC). MATERIALS AND METHODS: An orthotopic xenograft model of human RCC was used in which tumour cells were implanted in the left kidney of male 'severe combined immunodeficient' mice. Thalidomide was administered by intraperitoneal injection and after 34 days the mice were killed. The extent of tumour growth was compared in treated and untreated mice. Total RNA was extracted from both tumour-affected and contralateral kidneys, and analysed by reverse transcription-polymerase chain reaction for various genes implicated in angiogenesis and metastasis in RCC. RESULTS: Thalidomide failed to inhibit the growth of xenograft tumours. The expression of angiogenic genes, e.g. vascular endothelial growth factor and fibroblast growth factor type 2 (FGF-2) within normal and tumour-affected kidney tissue was not reduced by thalidomide. Intratumoral transcription of beta3-integrin, a critical component of angiogenesis, was significantly increased in response to thalidomide treatment (P < 0.01). There was also a trend to increased expression of FGF-2 and tumour necrosis factor-alpha in thalidomide-treated tumours. CONCLUSIONS: These findings suggest that RCC is capable of adapting to the inhibitory effects of thalidomide. The current uncertainty surrounding the action of thalidomide in vivo warrants caution about its use in humans. Further studies of thalidomide should be carried out in animal models, particularly to establish its safety and effectiveness as part of a combined therapeutic strategy.

An orthotopic xenograft model of human nonseminomatous germ cell tumour.

We have established the first example of an orthotopic xenograft model of human nonseminomatous germ cell tumour (NSGCT). This reproducible model exhibits many clinically relevant features including metastases to the retroperitoneal lymph nodes and lungs, making it an ideal tool for research into the development and progression of testicular germ cell tumours.