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This experiment was conducted to compare conventional (CON; 21 d) and shortened (SH; 10 d) close-up period, and evaluate the effect of shortened close-up period combined with feeding different metabolizable protein (MP) levels on dry matter (DM) intake, metabolic status, and performance of dairy cows. Forty-eight multiparous Holstein cows with similar parity, body weight (BW), and previous lactation milk yield were divided into 2 groups. The first group (n = 24) received the far-off diet from -60 to -21 d (CON), and the second group (n = 24) received same far-off diet from -60 to -10 d (SH) relative to expected parturition. Cows were then moved to individual stalls and randomly allocated to 1 of 3 close-up diets: low MP diet (LMP; MP = 79 g/kg of DM), medium MP diet (MMP; MP = 101 g/kg of DM), or high MP diet (HMP; MP = 118 g/kg of DM). Treatments were used in a 2 × 3 factorial arrangement with 2 lengths of close-up period (CON and SH) and 3 levels of MP (LMP, MMP, and HMP). All diets were fed for ad libitum intake during the close-up period. After calving, all cows received the same fresh cow diet. We found no interaction between close-up period length and MP levels for traits, except for postpartum serum fatty acids and β-hydroxybutyrate (BHB). The concentrations of postpartum serum fatty acids and BHB were higher on LMP than MMP and HMP diets in SH group. The cows of the SH group tended to produce less colostrum in the first milking than cows in CON group. The length of close-up period did not affect pre- and postpartum DM intake or energy balance of cows during the last week of prepartum, but cows of the CON group had greater BW changes during the last 3 wk before parturition than cows in SH group. Cows fed MMP and HMP diets consumed 1.2 and 1 kg more DM than for those fed LMP prepartum, respectively. The concentrations of prepartum BHB and Ca were higher for SH cows than CON group cows. Except for blood urea N concentration, no other blood metabolite in prepartum was affected by dietary MP. We found no effects of close-up period length or MP levels in the close-up diet on urinary pH, purine derivative excretion, and microbial N flow. Postpartum, milk yield was not affected by close-up period length, but cows in CON group tended to have higher 4% fat-corrected milk yield, had higher milk fat content and yield, had greater BW and body condition score loss, and higher energy negative balance than cows in the SH group. Cows fed MMP diet ate 1.8 kg more DM and yielded 3.37 kg more milk than those fed the LMP diet. Milk fat, protein, and lactose content, milk urea N, and somatic cell count were not affected by MP levels, but the yield of milk protein and lactose were higher on MMP diet than on LMP diet. Concentrations of postpartum serum fatty acids and BHB were decreased by shortening the close-up period length, but glucose, cholesterol, and triglyceride were similar between close-up groups. During the postpartum period, serum fatty acids, BHB, aminotransferase, and Ca concentrations were decreased by increasing the MP levels in the close-up diet. It appears from this data set that multiparous cows will benefit from a shortened close-up period, and feeding a moderate MP diet could improve DM intake, milk yield, and metabolic status of periparturient dairy cows.

This experiment was conducted to investigate the effects of different exogenous progesterone sources administrated after artificial insemination (AI) on serum progesterone (P(4) ) concentration and pregnancy rates in Holstein lactating cows. Sixty-four lactating Holstein dairy cows were allocated to four different treatments (n = 16 per treatment): the cows 1) were injected with physiological saline on days 5 and 13 after AI (control group); 2) were injected with progesterone on days 5 and 13 after AI (P group); 3) received controlled internal drug releasing device (CIDR) for a period from day 5 to 19 after AI (CIDR group); and 4) were injected with gonadotropin-releasing hormone (GnRH) agonist on days 5 and 13 after AI (GnRH group). Blood samples were collected on days 0 (AI day), 5, 13, 16 and 19 after AI to determine serum P(4) concentration. The results revealed a significant difference among treatment groups for serum P(4) concentration on days 13, 16 and 19 with the lowest concentration of serum P(4) for the control group. The pregnancy rate was also positively affected by all the treatments with CIDR having the greatest effect on pregnancy rate. Overall, the results indicated that CIDR has the greatest effect on serum P(4) concentration and pregnancy rate, although the administration of P and GnRH during days after AI increased serum P(4) concentration in lactating dairy cows as well.

The present study was conducted to evaluate the effects of three different treatment methods of canola meal (CM) on ruminal degradability of crude protein (CP) and dry matter (DM) in situ and apparent digestibility of nutrients in sheep. The fractionation of protein for treated CM was measured as well. Treatments were: T0 = CM with no treatment (control); T1 = treatment with formaldehyde; T2 = treatment with acetic acid; and T3 = heating treatment. The ruminal degradability of CP and DM was measured using four rumen fistulated Mehraban sheep. For digestibility trial twelve intact Mehraban sheep were used. The results showed that neutral detergent insoluble nitrogen (NDIN) contents were 5.28%, 5.29%, 6.25% and 5.16% and acid detergent insoluble nitrogen (ADIN) contents were 4.46%, 4.59%, 4.44% and 4.50% for T0, T1, T2 and T3, respectively ( P > 0.05). Considering nitrogen fractions, A + B 1 and B 2 showed differences among treatments ( P 3 and C being similar among treatments. The degradability kinetic parameters for DM ( a , b and c ) differed among treatments ( P a , b and c for CP degradability also were affected by treatments ( P P 2 and lower A + B 1 fractions compared with untreated CM and solubility of protein in CM decreased with different treatments. The results of the present study suggest that untreated CM has the greatest degradation rate in rumen and treating CM considerably decreased the solubility of protein and ruminal degradation rate. In conclusion the results suggest the treatment CM with formaldehyde to increase apparent digestibility of protein and the treatment CM with acetic acid to decrease ruminal degradation rate of protein.

The objective was to study the effects of partial replacement of soybean meal (SBM) with xylose-treated SBM (XSBM) as a source of rumen undegradable protein (RUP) in the starter concentrate of calves on performance, health status and selected blood metabolites. Twenty-one female Holstein dairy calves (body weight=39.6±2.3 kg) were randomly assigned to 3 groups (n=7 each): i) starter concentrate with 25% SBM [control (CTR)]; ii) starter concentrate with 17.5% SBM +7.5% XSBM (7.5XSBM); and iii) starter concentrate with 12.5% SBM+12.5% XSBM (12.5XSBM). Calves received 2 L of milk twice daily, with ad libitum access to starter concentrates from d 4 until weaning (d 56). Performance and health status were recorded throughout the experiment. Blood samples collected on d 4, 35 and 56 were assayed for concentrations of glucose, total protein (TP), and plasma urea nitrogen (PUN). Starter intake (560, 400, and 420 g/d for CTR, 7.5XSBM, and 12.5XSBM, respectively), average daily gain (0.67, 0.6 and 0.57 kg/d), and feed to gain ratio (0.83, 0.67, and 0.74) were affected by treatments (P

This study was carried out to investigate the effects of source and level of sulfur in dairy cow close-up diets on dry matter intake (DMI), blood metabolites and subsequent lactation performance. Twenty four individually fed multiparous close-up Holstein cows averaging body weight 687.9 kg were allocated in three different treatments (8 cows per each). The first treatment (T1) has contained 0.21% sulfur (DM basis), the second treatment (T2) has contained 0.41% sulfur which supplied through magnesium sulfate and the third treatment (T3) has contained 0.41% sulfur supplied through combination of magnesium sulfate and an organic source of sulfur (Mepron). All the cows were fed same diet after parturition until 21 d. The DMI for both pre- and postcalving was affected by treatments and T2 showed the lowest DMI among treatments. Glucose, calcium, and copper were decreased in T2. However, blood concentrations of BHBA, NEFA, urea, creatinine phosphokinase, and aspartate amino transferase were increased in T2. The results indicated that although magnesium sulfate has negative effect on dairy cow health and performance, a combination of magnesium sulfate and organic source of sulfur in close-up diets could have positive effects on DMI and performance of Holstein dairy cows.